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Bostanova FM, Tsygankova PG, Larshina EA, Nagornov IO, Evseeva YV, Krutikhina IL, Dzhentemirova ME, Kashlakova MN, Petukhova MS, Sharkova IV, Zakharova EY. Identification of a Novel Indel Variant in the DARS2 Gene in Russian Patients with Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Lactate Elevation. Genes (Basel) 2024; 15:615. [PMID: 38790244 PMCID: PMC11121371 DOI: 10.3390/genes15050615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation is an inherited disease caused by pathogenic biallelic variants in the gene DARS2, which encodes mitochondrial aspartyl-tRNA synthetase. This disease is characterized by slowly progressive spastic gait, cerebellar symptoms, and leukoencephalopathy with brainstem and spinal cord involvement. CASE PRESENTATION Peripheral blood samples were collected from four patients from four unrelated families to extract genomic DNA. All patients underwent partial exon analysis of the DARS2 gene using Sanger sequencing, which detected the c.228-21_228-20delinsC variant in a heterozygous state. Further DNA from three patients was analyzed using a next-generation sequencing-based custom AmpliSeq™ panel for 59 genes associated with leukodystrophies, and one of the patients underwent whole genome sequencing. We identified a novel pathogenic variant c.1675-1256_*115delinsGCAACATTTCGGCAACATTCCAACC in the DARS2 gene. Three patients (patients 1, 2, and 4) had slowly progressive cerebellar ataxia, and two patients (patients 1 and 2) had spasticity. In addition, two patients (patients 2 and 4) showed signs of axonal neuropathy, such as decreased tendon reflexes and loss of distal sensitivity. Three patients (patients 1, 2, and 3) also had learning difficulties. It should be noted the persistent presence of characteristic changes in brain MRI in all patients, which emphasizes its importance as the main diagnostic tool for suspicion and subsequent confirmation of LBSL. Conclusions: We found a novel indel variant in the DARS2 gene in four patients with LBSL and described their clinical and genetic characteristics. These results expand the mutational spectrum of LBSL and aim to improve the laboratory diagnosis of this form of leukodystrophy.
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Affiliation(s)
- Fatima M. Bostanova
- Research Centre for Medical Genetics, 1 Moskvorechye St., 115522 Moscow, Russia; (F.M.B.)
| | - Polina G. Tsygankova
- Research Centre for Medical Genetics, 1 Moskvorechye St., 115522 Moscow, Russia; (F.M.B.)
| | - Elena A. Larshina
- Research Centre for Medical Genetics, 1 Moskvorechye St., 115522 Moscow, Russia; (F.M.B.)
| | - Ilya O. Nagornov
- Research Centre for Medical Genetics, 1 Moskvorechye St., 115522 Moscow, Russia; (F.M.B.)
| | - Yulia V. Evseeva
- Ekaterinburg Research Institute of Viral Infections, 620030 Yekaterinburg, Russia
| | | | - Marina E. Dzhentemirova
- State Budgetary Healthcare Institution “Magadan Region Center for Maternal and Child Health”, 685000 Magadan, Russia
| | - Marina N. Kashlakova
- St. Petersburg State Budgetary Institution, City Polyclinic, No. 114, 197374 St. Petersburg, Russia
| | - Marina S. Petukhova
- Research Centre for Medical Genetics, 1 Moskvorechye St., 115522 Moscow, Russia; (F.M.B.)
| | - Inna V. Sharkova
- Research Centre for Medical Genetics, 1 Moskvorechye St., 115522 Moscow, Russia; (F.M.B.)
| | - Ekaterina Y. Zakharova
- Research Centre for Medical Genetics, 1 Moskvorechye St., 115522 Moscow, Russia; (F.M.B.)
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2
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Tyynismaa H. Disease models of mitochondrial aminoacyl-tRNA synthetase defects. J Inherit Metab Dis 2023; 46:817-823. [PMID: 37410890 DOI: 10.1002/jimd.12652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 06/12/2023] [Accepted: 06/30/2023] [Indexed: 07/08/2023]
Abstract
Mitochondrial aminoacyl-tRNA synthetases (mtARS) are enzymes critical for the first step of mitochondrial protein synthesis by charging mitochondrial tRNAs with their cognate amino acids. Pathogenic variants in all 19 nuclear mtARS genes are now recognized as causing recessive mitochondrial diseases. Most mtARS disorders affect the nervous system, but the phenotypes range from multisystem diseases to tissue-specific manifestations. However, the mechanisms behind the tissue specificities are poorly understood, and challenges remain in obtaining accurate disease models for developing and testing treatments. Here, some of the currently existing disease models that have increased our understanding of mtARS defects are discussed.
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Affiliation(s)
- Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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3
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Guang S, O'Brien BM, Fine AS, Ying M, Fatemi A, Nemeth CL. Mutations in DARS2 result in global dysregulation of mRNA metabolism and splicing. Sci Rep 2023; 13:13042. [PMID: 37563224 PMCID: PMC10415389 DOI: 10.1038/s41598-023-40107-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 08/04/2023] [Indexed: 08/12/2023] Open
Abstract
Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a rare neurological disorder caused by the mutations in the DARS2 gene, which encodes the mitochondrial aspartyl-tRNA synthetase. The objective of this study was to understand the impact of DARS2 mutations on cell processes through evaluation of LBSL patient stem cell derived cerebral organoids and neurons. We generated human cerebral organoids (hCOs) from induced pluripotent stem cells (iPSCs) of seven LBSL patients and three healthy controls using an unguided protocol. Single cells from 70-day-old hCOs were subjected to SMART-seq2 sequencing and bioinformatic analysis to acquire high-resolution gene and transcript expression datasets. Global gene expression analysis demonstrated dysregulation of a number of genes involved in mRNA metabolism and splicing processes within LBSL hCOs. Importantly, there were distinct and divergent gene expression profiles based on the nature of the DARS2 mutation. At the transcript level, pervasive differential transcript usage and differential spliced exon events that are involved in protein translation and metabolism were identified in LBSL hCOs. Single-cell analysis of DARS2 (exon 3) showed that some LBSL cells exclusively express transcripts lacking exon 3, indicating that not all LBSL cells can benefit from the "leaky" nature common to splice site mutations. At the gene- and transcript-level, we uncovered that dysregulated RNA splicing, protein translation and metabolism may underlie at least some of the pathophysiological mechanisms in LBSL. To confirm hCO findings, iPSC-derived neurons (iNs) were generated by overexpressing Neurogenin 2 using lentiviral vector to study neuronal growth, splicing of DARS2 exon 3 and DARS2 protein expression. Live cell imaging revealed neuronal growth defects of LBSL iNs, which was consistent with the finding of downregulated expression of genes related to neuronal differentiation in LBSL hCOs. DARS2 protein was downregulated in iNs compared to iPSCs, caused by increased exclusion of exon 3. The scope and complexity of our data imply that DARS2 is potentially involved in transcription regulation beyond its canonical role of aminoacylation. Nevertheless, our work highlights transcript-level dysregulation as a critical, and relatively unexplored, mechanism linking genetic data with neurodegenerative disorders.
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Affiliation(s)
- S Guang
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute, 707 N Broadway, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - B M O'Brien
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute, 707 N Broadway, Baltimore, MD, 21205, USA
| | - A S Fine
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, USA
| | - M Ying
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Kennedy Krieger Institute, Baltimore, MD, USA
| | - A Fatemi
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute, 707 N Broadway, Baltimore, MD, 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - C L Nemeth
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute, 707 N Broadway, Baltimore, MD, 21205, USA.
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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4
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Guang S, O'Brien B, Fine AS, Ying M, Fatemi A, Nemeth C. Mutations in DARS2 result in global dysregulation of mRNA metabolism and splicing. RESEARCH SQUARE 2023:rs.3.rs-2603446. [PMID: 36909591 PMCID: PMC10002802 DOI: 10.21203/rs.3.rs-2603446/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
Leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation (LBSL) is a rare neurological disorder caused by the mutations in the DARS2 gene, which encodes the mitochondrial aspartyl-tRNA synthetase. The objective of this study was to understand the impact of DARS2 mutations on cell processes through evaluation of LBSL patient stem cell derived cerebral organoids and neurons. We generated human cerebral organoids (hCOs) from induced pluripotent stem cells (iPSCs) of seven LBSL patients and three healthy controls using an unguided protocol. Single cells from 70-day-old hCOs underwent SMART-seq2 sequencing and multiple bioinformatic analysis tools were applied to high-resolution gene and transcript expression analyses. To confirm hCO findings, iPSC-derived neurons (iNs) were generated by overexpressing Neurogenin 2 using lentiviral vector to study neuronal growth, splicing of DARS2 exon 3 and DARS2 protein expression. Global gene expression analysis demonstrated dysregulation of a number of genes involved in mRNA metabolism and splicing processes within LBSL hCOs. Importantly, there were distinct and divergent gene expression profiles based on the nature of the DARS2 mutation. At the transcript level, pervasive differential transcript usage and differential spliced exon events that are involved in protein translation and metabolism were identified in LBSL hCOs. Single-cell analysis of DARS2 (exon 3) showed that some LBSL cells exclusively express transcripts lacking exon 3, indicating that not all LBSL cells can benefit from the "leaky" nature common to splice site mutations. Live cell imaging revealed neuronal growth defects of LBSL iNs, which was consistent with the finding of downregulated expression of genes related to neuronal differentiation in LBSL hCOs. DARS2 protein was downregulated in iNs compared to iPSCs, caused by increased exclusion of exon 3. At the gene- and transcript-level, we uncovered that dysregulated RNA splicing, protein translation and metabolism may underlie at least some of the pathophysiological mechanisms in LBSL. The scope and complexity of our data imply that DARS2 is potentially involved in transcription regulation beyond its canonical role of aminoacylation. Nevertheless, our work highlights transcript-level dysregulation as a critical, and relatively unexplored, mechanism linking genetic data with neurodegenerative disorders.
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Affiliation(s)
- Shiqi Guang
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute
| | - Brett O'Brien
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute
| | - Amena Smith Fine
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute
| | | | - Ali Fatemi
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute
| | - Christina Nemeth
- Moser Center for Leukodystrophies at Kennedy Krieger, Kennedy Krieger Institute
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5
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Amanat M, Nemeth CL, Fine AS, Leung DG, Fatemi A. Antisense Oligonucleotide Therapy for the Nervous System: From Bench to Bedside with Emphasis on Pediatric Neurology. Pharmaceutics 2022; 14:2389. [PMID: 36365206 PMCID: PMC9695718 DOI: 10.3390/pharmaceutics14112389] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 10/26/2022] [Accepted: 11/02/2022] [Indexed: 09/05/2023] Open
Abstract
Antisense oligonucleotides (ASOs) are disease-modifying agents affecting protein-coding and noncoding ribonucleic acids. Depending on the chemical modification and the location of hybridization, ASOs are able to reduce the level of toxic proteins, increase the level of functional protein, or modify the structure of impaired protein to improve function. There are multiple challenges in delivering ASOs to their site of action. Chemical modifications in the phosphodiester bond, nucleotide sugar, and nucleobase can increase structural thermodynamic stability and prevent ASO degradation. Furthermore, different particles, including viral vectors, conjugated peptides, conjugated antibodies, and nanocarriers, may improve ASO delivery. To date, six ASOs have been approved by the US Food and Drug Administration (FDA) in three neurological disorders: spinal muscular atrophy, Duchenne muscular dystrophy, and polyneuropathy caused by hereditary transthyretin amyloidosis. Ongoing preclinical and clinical studies are assessing the safety and efficacy of ASOs in multiple genetic and acquired neurological conditions. The current review provides an update on underlying mechanisms, design, chemical modifications, and delivery of ASOs. The administration of FDA-approved ASOs in neurological disorders is described, and current evidence on the safety and efficacy of ASOs in other neurological conditions, including pediatric neurological disorders, is reviewed.
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Affiliation(s)
- Man Amanat
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Christina L. Nemeth
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amena Smith Fine
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Doris G. Leung
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Center for Genetic Muscle Disorders, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Ali Fatemi
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, Baltimore, MD 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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6
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Smith Fine A, Kaufman M, Goodman J, Turk B, Bastian A, Lin D, Fatemi A, Keller J. Wearable sensors detect impaired gait and coordination in LBSL during remote assessments. Ann Clin Transl Neurol 2022; 9:468-477. [PMID: 35257509 PMCID: PMC8994975 DOI: 10.1002/acn3.51509] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 02/02/2023] Open
Abstract
Background Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a rare leukodystrophy with motor impairment due to biallelic mutations in DARS2, which encodes mitochondrial aspartyl tRNA synthetase. Progressive ataxia is the primary feature. Objective The study objective is to determine the feasibility of remotely collecting quantitative gait and balance measures in LBSL. Methods The study design uses wearable accelerometers and the scale for the assessment and rating of ataxia (SARA) scale to assess gait and postural sway in LBSL and control participants' homes through video conferencing. Results Lateral step variability (LSV), which indicates stride variability, and elevation of the step at mid‐swing are increased for LBSL patients during brief walking tests. During stance with the eyes closed, LBSL participants show rapid accelerations and decelerations of body movement covering a large sway area and path. Both the LSV and sway area during stance with the feet together and eyes closed correlate strongly with the SARA. Conclusions Wearable accelerometers are valid and sensitive for detecting ataxia in LBSL patients during remote assessments. The finding of large increases in the sway area during stance with the eyes closed is intriguing since dorsal column dysfunction is universally seen in LBSL. This approach can be applied to related rare diseases that feature ataxia.
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Affiliation(s)
- Amena Smith Fine
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Miriam Kaufman
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Jordan Goodman
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Bela Turk
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Amy Bastian
- Center for Movement Studies, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Doris Lin
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ali Fatemi
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Jennifer Keller
- Center for Movement Studies, Kennedy Krieger Institute, Baltimore, Maryland, USA
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7
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Rumyantseva A, Popovic M, Trifunovic A. CLPP deficiency ameliorates neurodegeneration caused by impaired mitochondrial protein synthesis. Brain 2022; 145:92-104. [PMID: 35240691 DOI: 10.1093/brain/awab303] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/01/2021] [Accepted: 07/14/2021] [Indexed: 11/12/2022] Open
Abstract
Mitochondria are essential organelles found in every eukaryotic cell, required to convert food into usable energy. Therefore, it is not surprising that mutations in either mtDNA or nuclear DNA-encoded genes of mitochondrial proteins cause diseases affecting the oxidative phosphorylation system, which are heterogeneous from a clinical, genetic, biochemical and molecular perspective and can affect patients at any age. Despite all this, it is surprising that our understanding of the mechanisms governing mitochondrial gene expression and its associated pathologies remain superficial and therapeutic interventions largely unexplored. We recently showed that loss of the mitochondrial matrix protease caseinolytic protease proteolytic subunit (CLPP) ameliorates phenotypes in cells characterized by defects in oxidative phosphorylation maintenance. Here, we build upon this finding by showing that CLPP depletion is indeed beneficial in vivo for various types of neuronal populations, including Purkinje cells in the cerebellum and cortical and hippocampal neurons in the forebrain, as it strongly improves distinct phenotypes of mitochondria encephalopathy, driven by the deficiency of the mitochondrial aspartyl tRNA synthase DARS2. In the absence of CLPP, neurodegeneration of DARS2-deficient neurons is delayed as they present milder oxidative phosphorylation dysfunction. This in turn leads to a decreased neuroinflammatory response and significantly improved motor functions in both double-deficient models (Purkinje cell-specific or forebrain neuron-specific Dars2/Clpp double knockout mice). We propose that diminished turnover of respiratory complex I caused by the loss of CLPP is behind the improved phenotype in Dars2/Clpp double knockout animals, even though this intervention might not restore respiratory complex I activity but rather improve mitochondrial cristae morphology or help maintain the NAD+/NADH ratio inside mitochondria. These results also open the possibility of targeting CLPP activity in many other mitochondrial encephalopathies characterized by respiratory complex I instability.
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Affiliation(s)
- Anastasia Rumyantseva
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Medical Faculty, University of Cologne, D-50931 Cologne, Germany.,Institute for Mitochondrial Diseases and Ageing, Medical Faculty and Center for Molecular Medicine Cologne (CMMC), D-50931 Cologne, Germany
| | - Milica Popovic
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Medical Faculty, University of Cologne, D-50931 Cologne, Germany.,Institute for Mitochondrial Diseases and Ageing, Medical Faculty and Center for Molecular Medicine Cologne (CMMC), D-50931 Cologne, Germany
| | - Aleksandra Trifunovic
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), Medical Faculty, University of Cologne, D-50931 Cologne, Germany.,Institute for Mitochondrial Diseases and Ageing, Medical Faculty and Center for Molecular Medicine Cologne (CMMC), D-50931 Cologne, Germany
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8
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Li JL, Lee NC, Chen PS, Lee GH, Wu RM. Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Lactate Elevation: A Novel DARS2 Mutation and Intra-Familial Heterogeneity. Mov Disord Clin Pract 2021; 8:1116-1122. [PMID: 34631948 PMCID: PMC8485606 DOI: 10.1002/mdc3.13281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 05/28/2021] [Accepted: 06/27/2021] [Indexed: 11/06/2022] Open
Abstract
Background Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is characterized by slowly progressive spastic gait, cerebellar symptoms, and posterior cord dysfunction. DARS2, which encodes mitochondrial aspartyl tRNA synthase, is associated with the rare disease. Cases The proband had gait disturbance since age 56, while her younger brother had the gait problem since his 20s and needed cane‐assistance at age 45. Both cases showed typical demyelinating features of LBSL on the magnetic resonance imaging (MRI) involving the periventricular white matter, brainstem, cerebellum and spinal cord. Sequencing of both cases showed compound heterozygous mutations: c.228‐16C>A and c.508C>T in DARS2. The c.228‐16C>A is a common mutation in splicing site of intron 2, which causes alternative splicing defect of exon 3, while the c.508C>T at the exon 6 is novel. Our patients are unique in the relative late onset and the apparent difference in disease progression. Literature Review Literatures from PubMed were reviewed. Five families showed intra‐familial heterogeneity on age at onset or clinical severity. Conclusion We identified a family of LBSL with compound heterozygous mutations, and c.508C>T at the exon 6 is a novel one. Clinical heterogeneity was observed in the family and other literatures. Further research for underlying mechanism is required.
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Affiliation(s)
- Jeng-Lin Li
- Department of Neurology National Taiwan University Hospital Taipei Taiwan
| | - Ni-Chung Lee
- Department of Medical Genetics National Taiwan University Hospital Taipei Taiwan
| | - Pin-Shiuan Chen
- Department of Neurology National Taiwan University Hospital Taipei Taiwan
| | - Gin Hoong Lee
- Department of Neurology National Taiwan University Hospital Taipei Taiwan.,Department of Medical Education National Taiwan University Hospital Taipei Taiwan
| | - Ruey-Meei Wu
- Department of Neurology National Taiwan University Hospital Taipei Taiwan.,Department of Neurology, College of Medicine National Taiwan University Taipei Taiwan
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9
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Sawada D, Naito S, Aoyama H, Shiohama T, Ichikawa T, Imagawa E, Miyake N, Matsumoto N, Fujii K. Remitting and exacerbating white matter lesions in leukoencephalopathy with thalamus and brainstem involvement and high lactate. Brain Dev 2021; 43:798-803. [PMID: 33962821 DOI: 10.1016/j.braindev.2021.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/28/2021] [Accepted: 03/30/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) is a hereditary disorder caused by biallelic variants in the EARS2 gene. Patients exhibit developmental delay, hypotonia, and hyperreflexia. Brain magnetic resonance imaging (MRI) reveals T2-hyperintensities in the deep white matter, thalamus, and brainstem, which generally stabilize over time. Herein, we report a case of LTBL, showing remitting and exacerbating white matter lesions. CASE DESCRIPTION A non-consanguineous Japanese boy exhibited unsteady head control with prominent hypotonia, with no family history of neurological diseases. Brain MRI at one year of age revealed extensive T2-hyperintensities on the cerebral white matter, cerebellum, thalamus, basal ganglia, pons, and medulla oblongata. Magnetic resonance spectroscopy of the lesions showed lactate and myoinositol peaks. Whole-exome sequencing yielded novel compound heterozygous EARS2 variants of c.164G>T, p.Arg55Leu and c.484C>T, p.Arg162Trp. Interestingly, the lesions were reduced at three years of age, and new lesions emerged at eight years of age. At 10 years of age, the lesions were changed in the corpus callosum, deep cerebral white matter, and cerebellum, without physical exacerbation. The lesions improved one year later. CONCLUSION We present the first case with remitting and exacerbating brain lesions in LTBL. EARS2 could relate to selective and specific brain regions and age dependency. Although the exact role of EARS2 remains unknown, the remitting and exacerbating imaging changes may be a clue in elucidating a novel EARS2 function in LTBL.
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Affiliation(s)
- Daisuke Sawada
- Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan.
| | - Sachiko Naito
- Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan; Division of Clinical Genetics, Chiba University Hospital, Chiba, Japan
| | - Hiromi Aoyama
- Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Tadashi Shiohama
- Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan
| | - Tomohiko Ichikawa
- Division of Clinical Genetics, Chiba University Hospital, Chiba, Japan
| | - Eri Imagawa
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Katsunori Fujii
- Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan
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10
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Stellingwerff MD, Figuccia S, Bellacchio E, Alvarez K, Castiglioni C, Topaloglu P, Stutterd CA, Erasmus CE, Sanchez-Valle A, Lebon S, Hughes S, Schmitt-Mechelke T, Vasco G, Chow G, Rahikkala E, Dallabona C, Okuma C, Aiello C, Goffrini P, Abbink TEM, Bertini ES, Van der Knaap MS. LBSL: Case Series and DARS2 Variant Analysis in Early Severe Forms With Unexpected Presentations. NEUROLOGY-GENETICS 2021; 7:e559. [PMID: 33977142 PMCID: PMC8105885 DOI: 10.1212/nxg.0000000000000559] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 12/03/2020] [Indexed: 02/07/2023]
Abstract
Objective Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is regarded a relatively mild leukodystrophy, diagnosed by characteristic long tract abnormalities on MRI and biallelic variants in DARS2, encoding mitochondrial aspartyl-tRNA synthetase (mtAspRS). DARS2 variants in LBSL are almost invariably compound heterozygous; in 95% of cases, 1 is a leaky splice site variant in intron 2. A few severely affected patients, still fulfilling the MRI criteria, have been described. We noticed highly unusual MRI presentations in 15 cases diagnosed by WES. We examined these cases to determine whether they represent consistent novel LBSL phenotypes. Methods We reviewed clinical features, MRI abnormalities, and gene variants and investigated the variants' impact on mtAspRS structure and mitochondrial function. Results We found 2 MRI phenotypes: early severe cerebral hypoplasia/atrophy (9 patients, group 1) and white matter abnormalities without long tract involvement (6 patients, group 2). With antenatal onset, microcephaly, and arrested development, group 1 patients were most severely affected. DARS2 variants were severer than for classic LBSL and severer for group 1 than group 2. All missense variants hit mtAspRS regions involved in tRNAAsp binding, aspartyl-adenosine-5′-monophosphate binding, and/or homodimerization. Missense variants expressed in the yeast DARS2 ortholog showed severely affected mitochondrial function. Conclusions DARS2 variants are associated with highly heterogeneous phenotypes. New MRI presentations are profound cerebral hypoplasia/atrophy and white matter abnormalities without long tract involvement. Our findings have implications for diagnosis and understanding disease mechanisms, pointing at dominant neuronal/axonal involvement in severe cases. In line with this conclusion, activation of biallelic DARS2 null alleles in conditional transgenic mice leads to massive neuronal apoptosis.
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Affiliation(s)
- Menno D Stellingwerff
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Sonia Figuccia
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Emanuele Bellacchio
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Karin Alvarez
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Claudia Castiglioni
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Pinar Topaloglu
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Chloe A Stutterd
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Corrie E Erasmus
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Amarilis Sanchez-Valle
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Sebastien Lebon
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Sarah Hughes
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Thomas Schmitt-Mechelke
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Gessica Vasco
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Gabriel Chow
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Elisa Rahikkala
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Cristina Dallabona
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Cecilia Okuma
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Chiara Aiello
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Paola Goffrini
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Truus E M Abbink
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Enrico S Bertini
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
| | - Marjo S Van der Knaap
- Department of Child Neurology, Emma Childrens Hospital, Amsterdam University Medical Centers, Vrije Universiteit and Amsterdam Neuroscience, The Netherlands (M.D.S., T.E.M.A.); Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Italy (S.F., C.D., P.G.); Area di Ricerca Genetica e Malattie Rare (E.B.), Ospedale Pediatrico Bambino Gesù, IRCCS, Rome, Italy; Laboratory of Oncology and Molecular Genetics (K.A.), Clínica las Condes, Santiago, Chile; Department of Pediatric Neurology (C.C.), Clínica Las Condes, Santiago, Chile; Division of Child Neurology (P.T.), Department of Neurology, Istanbul Faculty of Medicine, Turkey; Department of Paediatrics (C.A.S.), Royal Childrens Hospital, Murdoch Childrens Research Institute and University of Melbourne, Victoria, Australia; Pediatric Neurology (C.E.E.), Radboud University Medical Center, Amalia Childrens Hospital, Nijmegen, The Netherlands; Department of Pediatrics (A.S.-V.), University of South Florida, Tampa; Unit of Pediatric Neurology and Neurorehabilitation (S.L.), Department WomanMother-Child, Lausanne University Hospital, Switzerland; Community Pediatrics, Royal Berkshire Hospital, Reading (S.H.), United Kingdom; Neuropediatric Department (T.S.-M.), Childrens Hospital, Luzern, Switzerland; Unit of Neurorehabilitation (G.V.), Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; Paediatric Neurology (G.C.), Nottingham Childrens Hospital, United Kingdom; PEDEGO Research Unit (E.R.), Medical Research Center and Department of Clinical Genetics, University of Oulu and Oulu University Hospital, Finland; Radiology (C.O.), Clínica las Condes, Santiago, Chile; Unit of Neuromuscular and Neurodegenerative Disorders (E.S.B), Area di Ricerca Genetica e Malattie Rare and Department of Neurosciences, Bambino Gesù Children's Research Hospital, IRCCS, Rome, Italy; and Department of Child Neurology (M.S.v.d.K.), Emma Childrens Hospital and Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands
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11
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Muthiah A, Housley GD, Klugmann M, Fröhlich D. The Leukodystrophies HBSL and LBSL-Correlates and Distinctions. Front Cell Neurosci 2021; 14:626610. [PMID: 33574740 PMCID: PMC7870476 DOI: 10.3389/fncel.2020.626610] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/21/2020] [Indexed: 12/16/2022] Open
Abstract
Aminoacyl-tRNA synthetases (ARSs) accurately charge tRNAs with their respective amino acids. As such, they are vital for the initiation of cytosolic and mitochondrial protein translation. These enzymes have become increasingly scrutinized in recent years for their role in neurodegenerative disorders caused by the mutations of ARS-encoding genes. This review focuses on two such genes-DARS1 and DARS2-which encode cytosolic and mitochondrial aspartyl-tRNA synthetases, and the clinical conditions associated with mutations of these genes. We also describe attempts made at modeling these conditions in mice, which have both yielded important mechanistic insights. Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a disease caused by a range of mutations in the DARS2 gene, initially identified in 2003. Ten years later, hypomyelination with brainstem and spinal cord involvement and leg spasticity (HBSL), caused by mutations of cytosolic DARS1, was discovered. Multiple parallels have been drawn between the two conditions. The Magnetic Resonance Imaging (MRI) patterns are strikingly similar, but still set these two conditions apart from other leukodystrophies. Clinically, both conditions are characterized by lower limb spasticity, often associated with other pyramidal signs. However, perhaps due to earlier detection, a wider range of symptoms, including peripheral neuropathy, as well as visual and hearing changes have been described in LBSL patients. Both HBSL and LBSL are spectrum disorders lacking genotype to phenotype correlation. While the fatal phenotype of Dars1 or Dars2 single gene deletion mouse mutants revealed that the two enzymes lack functional redundancy, further pursuit of disease modeling are required to shed light onto the underlying disease mechanism, and enable examination of experimental treatments, including gene therapies.
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Affiliation(s)
| | | | | | - Dominik Fröhlich
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia
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12
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Fröhlich D, Mendes MI, Kueh AJ, Bongers A, Herold MJ, Salomons GS, Housley GD, Klugmann M. A Hypomorphic Dars1 D367Y Model Recapitulates Key Aspects of the Leukodystrophy HBSL. Front Cell Neurosci 2021; 14:625879. [PMID: 33551752 PMCID: PMC7855723 DOI: 10.3389/fncel.2020.625879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 12/21/2020] [Indexed: 01/18/2023] Open
Abstract
Hypomyelination with brain stem and spinal cord involvement and leg spasticity (HBSL) is a leukodystrophy caused by missense mutations of the aspartyl-tRNA synthetase-encoding gene DARS1. The clinical picture includes the regression of acquired motor milestones, spasticity, ataxia, seizures, nystagmus, and intellectual disabilities. Morphologically, HBSL is characterized by a distinct pattern of hypomyelination in the central nervous system including the anterior brainstem, the cerebellar peduncles and the supratentorial white matter as well as the dorsal columns and the lateral corticospinal tracts of the spinal cord. Adequate HBSL animal models are lacking. Dars1 knockout mice are embryonic lethal precluding examination of the etiology. To address this, we introduced the HBSL-causing Dars1 D367Y point mutation into the mouse genome. Surprisingly, mice carrying this mutation homozygously were phenotypically normal. As hypomorphic mutations are more severe in trans to a deletion, we crossed Dars1 D367Y/D367Y mice with Dars1-null carriers. The resulting Dars1 D367Y/- offspring displayed a strong developmental delay compared to control Dars1 D367Y/+ littermates, starting during embryogenesis. Only a small fraction of Dars1 D367Y/- mice were born, and half of these mice died with hydrocephalus during the first 3 weeks of life. Of the few Dars1 D367Y/- mice that were born at term, 25% displayed microphthalmia. Throughout postnatal life, Dars1 D367Y/- mice remained smaller and lighter than their Dars1 D367Y/+ littermates. Despite this early developmental deficit, once they made it through early adolescence Dars1 D367Y/- mice were phenotypically inconspicuous for most of their adult life, until they developed late onset motor deficits as well as vacuolization and demyelination of the spinal cord white matter. Expression levels of the major myelin proteins were reduced in Dars1 D367Y/- mice compared to controls. Taken together, Dars1 D367Y/- mice model aspects of the clinical picture of the corresponding missense mutation in HBSL. This model will enable studies of late onset deficits, which is precluded in Dars1 knockout mice, and can be leveraged to test potential HBSL therapeutics including DARS1 gene replacement therapy.
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Affiliation(s)
- Dominik Fröhlich
- Translational Neuroscience Facility & Department of Physiology, School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia
| | - Marisa I. Mendes
- Metabolic Unit/Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam Gastroenterology & Metabolism, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Andrew J. Kueh
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Andre Bongers
- Biomedical Resources Imaging Laboratory, UNSW Sydney, Kensington, NSW, Australia
| | - Marco J. Herold
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Gajja S. Salomons
- Metabolic Unit/Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam Neuroscience, Amsterdam Gastroenterology & Metabolism, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Gary D. Housley
- Translational Neuroscience Facility & Department of Physiology, School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility & Department of Physiology, School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia
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13
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Chandra SR, Padmanabha H, Gupta M, Pruthi N, Narayanappa G, Christopher R. Myelopathy in Two Brothers with Respiratory Chain Disorder-Severe Complex 1 Deficiency with Atlantoaxial Dislocation and Long Spinal Arachnoid Cyst: A New Unreported Association. J Pediatr Neurosci 2020; 15:45-50. [PMID: 32435307 PMCID: PMC7227760 DOI: 10.4103/jpn.jpn_94_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 11/18/2019] [Accepted: 11/22/2019] [Indexed: 11/05/2022] Open
Abstract
Billion of years ago bacteria is believed to have entered a eukaryotic cell and converted to mitochondria. The respiratory chain present in it supplies ATP to all cells and therefore the diseases can have any phenotype. Diagnosis may be difficult to confirm by the conventional methods including genetics. Two brothers born to consanguineous parents had global delay, mild visual impairment and drooping of eyelids since birth in the elder child and dysmorphism in the second one. Both had progressive myelopathy due to retroflexed odontoid ,large arachnoid cyst and tethered cord. Muscle biopsy with special stain was normal but respiratory chain assay revealed severe complex 1 deficiency.Elder child underwent surgical decompression of the arachnoid cyst with duroplasty with significant improvement.Atlanto axial dislocation and large arachnoid cyst as cause of myelopathy is not reported in literature in patients with respiratory chain disorders to the best of our knowledge.
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Affiliation(s)
| | - Hansashree Padmanabha
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Manisha Gupta
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Nupur Pruthi
- Department of Neurosurgery, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Gayathri Narayanappa
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
| | - Rita Christopher
- Department of Neurochemistry, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India
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14
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Nemeth CL, Tomlinson SN, Rosen M, O'Brien BM, Larraza O, Jain M, Murray CF, Marx JS, Delannoy M, Fine AS, Wu D, Trifunovic A, Fatemi A. Neuronal ablation of mt-AspRS in mice induces immune pathway activation prior to severe and progressive cortical and behavioral disruption. Exp Neurol 2020; 326:113164. [PMID: 31887305 PMCID: PMC7448750 DOI: 10.1016/j.expneurol.2019.113164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/23/2019] [Accepted: 12/26/2019] [Indexed: 12/22/2022]
Abstract
Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a rare, slowly progressive white matter disease caused by mutations in the mitochondrial aspartyl-tRNA synthetase (mt-AspRS, or DARS2). While patients show characteristic MRI T2 signal abnormalities throughout the cerebral white matter, brainstem, and spinal cord, the phenotypic spectrum is broad and a multitude of gene variants have been associated with the disease. Here, Dars2 disruption in CamKIIα-expressing cortical and hippocampal neurons results in slowly progressive increases in behavioral activity at five months, and culminating by nine months as severe brain atrophy, behavioral dysfunction, reduced corpus callosum thickness, and microglial morphology indicative of neuroinflammation. Interestingly, RNAseq based gene expression studies performed prior to the presentation of this severe phenotype reveal the upregulation of several pathways involved in immune activation, cytokine production and signaling, and defense response regulation. RNA transcript analysis demonstrates that activation of immune and cell stress pathways are initiated in advance of a behavioral phenotype and cerebral deficits. An understanding of these pathways and their contribution to significant neuronal loss in CamKII-Dars2 deficient mice may aid in deciphering mechanisms of LBSL pathology.
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Affiliation(s)
| | | | - Melissa Rosen
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, USA
| | - Brett M O'Brien
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, USA
| | - Oscar Larraza
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, USA
| | - Mahim Jain
- Bone and Osteogenesis Imperfecta Department, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Connor F Murray
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, USA
| | - Joel S Marx
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, USA
| | - Michael Delannoy
- Johns Hopkins University, School of Medicine Microscope Facility, Baltimore, MD, USA
| | - Amena S Fine
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, USA; Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Dan Wu
- Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Aleksandra Trifunovic
- CECAD Research Centre, Institute for Mitochondrial Diseases and Aging, Center for Molecular Medicine Cologne, Medical Faculty, University of Cologne, Cologne, Germany
| | - Ali Fatemi
- Moser Center for Leukodystrophies, Kennedy Krieger Institute, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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15
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Peretz M, Tworowski D, Kartvelishvili E, Livingston J, Chrzanowska-Lightowlers Z, Safro M. Breaking a single hydrogen bond in the mitochondrial tRNA Phe -PheRS complex leads to phenotypic pleiotropy of human disease. FEBS J 2020; 287:3814-3826. [PMID: 32115907 PMCID: PMC7540514 DOI: 10.1111/febs.15268] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/09/2020] [Accepted: 02/27/2020] [Indexed: 01/19/2023]
Abstract
Various pathogenic variants in both mitochondrial tRNAPhe and Phenylalanyl‐tRNA synthetase mitochondrial protein coding gene (FARS2) gene encoding for the human mitochondrial PheRS have been identified and associated with neurological and/or muscle‐related pathologies. An important Guanine‐34 (G34)A anticodon mutation associated with myoclonic epilepsy with ragged red fibers (MERRF) syndrome has been reported in hmit‐tRNAPhe. The majority of G34 contacts in available aaRSs‐tRNAs complexes specifically use that base as an important tRNA identity element. The network of intermolecular interactions providing its specific recognition also largely conserved. However, their conservation depends also on the invariance of the residues in the anticodon binding domain (ABD) of human mitochondrial Phenylalanyl‐tRNA synthetase (hmit‐PheRS). A defect in recognition of the anticodon of tRNAPhe may happen not only because of G34A mutation, but also due to mutations in the ABD. Indeed, a pathogenic mutation in FARS2 has been recently reported in a 9‐year‐old female patient harboring a p.Asp364Gly mutation. Asp364 is hydrogen bonded (HB) to G34 in WT hmit‐PheRS. Thus, there are two pathogenic variants disrupting HB between G34 and Asp364: one is associated with G34A mutation, and the other with Asp364Gly mutation. We have measured the rates of tRNAPhe aminoacylation catalyzed by WT hmit‐PheRS and mutant enzymes. These data ranked the residues making a HB with G34 according to their contribution to activity and the signal transduction pathway in the hmit‐PheRS‐tRNAPhe complex. Furthermore, we carried out extensive MD simulations to reveal the interdomain contact topology on the dynamic trajectories of the complex, and gaining insight into the structural and dynamic integrity effects of hmit‐PheRS complexed with tRNAPhe. Database Structural data are available in PDB database under the accession number(s): 3CMQ, 3TUP, 5MGH, 5MGV.
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Affiliation(s)
- Moshe Peretz
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Dmitry Tworowski
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | | | | | | | - Mark Safro
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
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Fine AS, Nemeth CL, Kaufman ML, Fatemi A. Mitochondrial aminoacyl-tRNA synthetase disorders: an emerging group of developmental disorders of myelination. J Neurodev Disord 2019; 11:29. [PMID: 31839000 PMCID: PMC6913031 DOI: 10.1186/s11689-019-9292-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 11/11/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The mitochondrial aminoacyl-tRNA synthetase proteins (mt-aaRSs) are a group of nuclear-encoded enzymes that facilitate conjugation of each of the 20 amino acids to its cognate tRNA molecule. Mitochondrial diseases are a large, clinically heterogeneous group of disorders with diverse etiologies, ages of onset, and involved organ systems. Diseases related to mt-aaRS mutations are associated with specific syndromes that affect the central nervous system and produce highly characteristic MRI patterns, prototypically the DARS2, EARS, and AARS2 leukodystrophies, which are caused by mutations in mitochondrial aspartyl-tRNA synthetase, mitochondria glutamate tRNA synthetase, and mitochondrial alanyl-tRNA synthetase, respectively. BODY: The disease patterns emerging for these leukodystrophies are distinct in terms of the age of onset, nature of disease progression, and predominance of involved white matter tracts. In DARS2 and EARS2 disorders, earlier disease onset is typically correlated with more significant brain abnormalities, rapid neurological decline, and greater disability. In AARS2 leukodystrophy cases reported thus far, there is nearly invariable progression to severe disability and atrophy of involved brain regions, often within a decade. Although most mutations are compound heterozygous inherited in an autosomal recessive fashion, homozygous variants are found in each disorder and demonstrate high phenotypic variability. Affected siblings manifest disease on a wide spectrum. CONCLUSION The syndromic nature and selective vulnerability of white matter tracts in these disorders suggests there may be a shared mechanism of mitochondrial dysfunction to target for study. There is evidence that the clinical variability and white matter tract specificity of each mt-aaRS leukodystrophy depend on both canonical and non-canonical effects of the mutations on the process of mitochondrial translation. Furthermore, different sensitivities to the mt-aaRS mutations have been observed based on cell type. Most mutations result in at least partial retention of mt-aaRS enzyme function with varied effects on the mitochondrial respiratory chain complexes. In EARS2 and AARS2 cells, this appears to result in cumulative impairment of respiration. Mt-aaRS mutations may also affect alternative biochemical pathways such as the integrated stress response, a homeostatic program in eukaryotic cells that typically confers cytoprotection, but can lead to cell death when abnormally activated in response to pathologic states. Systematic review of this group of disorders and further exploration of disease mechanisms in disease models and neural cells are warranted.
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Affiliation(s)
- Amena Smith Fine
- Moser Center for Leukodystrophies at the Kennedy Krieger Institute, Baltimore, MD 21205 USA
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD 21205 USA
| | - Christina L. Nemeth
- Moser Center for Leukodystrophies at the Kennedy Krieger Institute, Baltimore, MD 21205 USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287 USA
| | - Miriam L. Kaufman
- Moser Center for Leukodystrophies at the Kennedy Krieger Institute, Baltimore, MD 21205 USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287 USA
| | - Ali Fatemi
- Moser Center for Leukodystrophies at the Kennedy Krieger Institute, Baltimore, MD 21205 USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287 USA
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Mitochondrial dysfunctions in leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL). PLoS One 2019; 14:e0224173. [PMID: 31671122 PMCID: PMC6822708 DOI: 10.1371/journal.pone.0224173] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/07/2019] [Indexed: 02/07/2023] Open
Abstract
Several inherited human diseases have been linked to mitochondrial aminoacyl-tRNA synthetases (mtARSs). Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a leukodystrophy caused by mutations in the DARS2 gene which encodes mitochondrial aspartyl-tRNA synthetase. As mitochondrial ARSs are key components of the mitochondrial translation apparatus, we investigated the effects of DARS2 mutations on mitochondrial functions and mitochondrial morphology in an LBSL patient. In fibroblasts from the patient with LBSL, biosynthesis of respiratory chain complex proteins encoded by mitochondrial DNA was decreased, while those encoded by nuclear DNA were not. Cellular oxygen consumption rates and respiratory control ratio were decreased in the LBSL patient; in addition, fragmentation of mitochondria was increased, while their tubular elongation and interconnectivity were decreased. Taken together, these findings suggest that DARS2 mutations impair translations of mitochondrial DNA-encoded respiratory chain complex proteins, consequently causing dysfunction of cellular respiration and impediment of mitochondrial dynamics, which highlights the role of mtARSs in the maintenance of normal mitochondrial bioenergetics and dynamics.
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Finsterer J, Zarrouk-Mahjoub S. Involvement of the Spinal Cord in Mitochondrial Disorders. J Neurosci Rural Pract 2019; 9:245-251. [PMID: 29725177 PMCID: PMC5912032 DOI: 10.4103/jnrp.jnrp_446_17] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
This review aims at summarising and discussing the current status concerning the clinical presentation, pathogenesis, diagnosis, and treatment of spinal cord affection in mitochondrial disorders (MIDs). A literature search using the database Pubmed was carried out by application of appropriate search terms and their combinations. Involvement of the spinal cord in MIDs is more frequent than anticipated. It occurs in specific and non-specific MIDs. Among the specific MIDs it has been most frequently described in LBSL, LS, MERRF, KSS, IOSCA, MIRAS, and PCH and only rarely in MELAS, CPEO, and LHON. Clinically, spinal cord involvement manifests as monoparesis, paraparesis, quadruparesis, sensory disturbances, hypotonia, spasticity, urinary or defecation dysfunction, spinal column deformities, or as transverse syndrome. Diagnosing spinal cord involvement in MIDs requires a thoroughly taken history, clinical exam, and imaging studies. Additionally, transcranial magnetic stimulation, somato-sensory-evoked potentials, and cerebro-spinal fluid can be supportive. Treatment is generally not at variance compared to the underlying MID but occasionally surgical stabilisation of the spinal column may be necessary. It is concluded that spinal cord involvement in MIDs is more frequent than anticipated but may be missed if cerebral manifestations prevail. Spinal cord involvement in MIDs may strongly determine the mobility of these patients.
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Affiliation(s)
- Josef Finsterer
- Department of Neurology, Krankenanstalt Rudolfstiftung, Vienna, Austria
| | - Sinda Zarrouk-Mahjoub
- Pasteur Institute of Tunis, University of Tunis El Manar and Genomics Platform, Pasteur Institute of Tunis, Tunis, Tunisia
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González-Serrano LE, Chihade JW, Sissler M. When a common biological role does not imply common disease outcomes: Disparate pathology linked to human mitochondrial aminoacyl-tRNA synthetases. J Biol Chem 2019; 294:5309-5320. [PMID: 30647134 PMCID: PMC6462531 DOI: 10.1074/jbc.rev118.002953] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial aminoacyl-tRNA synthetases (mt-aaRSs) are essential components of the mitochondrial translation machinery. The correlation of mitochondrial disorders with mutations in these enzymes has raised the interest of the scientific community over the past several years. Most surprising has been the wide-ranging presentation of clinical manifestations in patients with mt-aaRS mutations, despite the enzymes' common biochemical role. Even among cases where a common physiological system is affected, phenotypes, severity, and age of onset varies depending on which mt-aaRS is mutated. Here, we review work done thus far and propose a categorization of diseases based on tissue specificity that highlights emerging patterns. We further discuss multiple in vitro and in cellulo efforts to characterize the behavior of WT and mutant mt-aaRSs that have shaped hypotheses about the molecular causes of these pathologies. Much remains to do in order to complete our understanding of these proteins. We expect that futher work is likely to result in the discovery of new roles for the mt-aaRSs in addition to their fundamental function in mitochondrial translation, informing the development of treatment strategies and diagnoses.
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Affiliation(s)
- Ligia Elena González-Serrano
- From the Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France and
| | - Joseph W Chihade
- the Department of Chemistry, Carleton College, Northfield, Minnesota 55057
| | - Marie Sissler
- From the Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France and
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20
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van der Knaap MS, Bugiani M, Mendes MI, Riley LG, Smith DEC, Rudinger-Thirion J, Frugier M, Breur M, Crawford J, van Gaalen J, Schouten M, Willems M, Waisfisz Q, Mau-Them FT, Rodenburg RJ, Taft RJ, Keren B, Christodoulou J, Depienne C, Simons C, Salomons GS, Mochel F. Biallelic variants in LARS2 and KARS cause deafness and (ovario)leukodystrophy. Neurology 2019; 92:e1225-e1237. [PMID: 30737337 DOI: 10.1212/wnl.0000000000007098] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/06/2018] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To describe the leukodystrophy caused by pathogenic variants in LARS2 and KARS, encoding mitochondrial leucyl transfer RNA (tRNA) synthase and mitochondrial and cytoplasmic lysyl tRNA synthase, respectively. METHODS We composed a group of 5 patients with leukodystrophy, in whom whole-genome or whole-exome sequencing revealed pathogenic variants in LARS2 or KARS. Clinical information, brain MRIs, and postmortem brain autopsy data were collected. We assessed aminoacylation activities of purified mutant recombinant mitochondrial leucyl tRNA synthase and performed aminoacylation assays on patients' lymphoblasts and fibroblasts. RESULTS Patients had a combination of early-onset deafness and later-onset neurologic deterioration caused by progressive brain white matter abnormalities on MRI. Female patients with LARS2 pathogenic variants had premature ovarian failure. In 2 patients, MRI showed additional signs of early-onset vascular abnormalities. In 2 other patients with LARS2 and KARS pathogenic variants, magnetic resonance spectroscopy revealed elevated white matter lactate, suggesting mitochondrial disease. Pathology in one patient with LARS2 pathogenic variants displayed evidence of primary disease of oligodendrocytes and astrocytes with lack of myelin and deficient astrogliosis. Aminoacylation activities of purified recombinant mutant leucyl tRNA synthase showed a 3-fold loss of catalytic efficiency. Aminoacylation assays on patients' lymphoblasts and fibroblasts showed about 50% reduction of enzyme activity. CONCLUSION This study adds LARS2 and KARS pathogenic variants as gene defects that may underlie deafness, ovarian failure, and leukodystrophy with mitochondrial signature. We discuss the specific MRI characteristics shared by leukodystrophies caused by mitochondrial tRNA synthase defects. We propose to add aminoacylation assays as biochemical diagnostic tools for leukodystrophies.
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Affiliation(s)
- Marjo S van der Knaap
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France.
| | - Marianna Bugiani
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Marisa I Mendes
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Lisa G Riley
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Desiree E C Smith
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Joëlle Rudinger-Thirion
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Magali Frugier
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Marjolein Breur
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Joanna Crawford
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Judith van Gaalen
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Meyke Schouten
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Marjolaine Willems
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Quinten Waisfisz
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Frederic Tran Mau-Them
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Richard J Rodenburg
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Ryan J Taft
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Boris Keren
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - John Christodoulou
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Christel Depienne
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Cas Simons
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Gajja S Salomons
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
| | - Fanny Mochel
- From the Departments of Child Neurology (M.S.v.d.K., M. Breur) and Neuropathology (M. Bugiani, M. Breur), and Metabolic Unit, Department of Clinical Chemistry (M.I.M., D.E.C.S., G.S.S.), Amsterdam University Medical Centers and Amsterdam Neuroscience; Department of Functional Genomics (M.S.v.d.K.), Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, the Netherlands; Genetic Metabolic Disorders Research Unit (L.G.R., J. Christodoulou), The Children's Hospital at Westmead, and Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, NSW, Australia; Architecture et Réactivité de l'ARN (J.R.-T., M.F.), UPR 9002, Université de Strasbourg, CNRS, Strasbourg, France; Institute for Molecular Bioscience (J. Crawford, C.S.), University of Queensland, St. Lucia, Queensland, Australia; Department of Neurology (J.v.G.), Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen; Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Departement Génétique Médicale (M.W.), Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHRU de Montpellier, France; Department of Clinical Genetics (Q.W.), Amsterdam University Medical Centers, the Netherlands; UF Innovation en Diagnostic Génomique des Maladies Rares (F.T.M.-T.), Centre Hospitalier Universitaire de Dijon, France; Radboud Center for Mitochondrial Medicine (R.J.R.), Translational Metabolic Laboratory, Department of Pediatrics, Radboud University Medical Center, Nijmegen, the Netherlands; Illumina Inc. (R.J.T.), San Diego, CA; AP-HP (B.K., F.M.), La Pitié-Salpêtrière University Hospital, Department of Genetics, Paris; INSERM U 1127 (B.K., C.D., F.M.), CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, Paris, France; Murdoch Children's Research Institute (J. Christodoulou, C.S.), Parkville, Victoria, Australia; Department of Paediatrics (J. Christodoulou), University of Melbourne, Australia; Institute of Human Genetics (C.D.), University Hospital Essen, University Duisburg-Essen, Germany; and Sorbonne Universités (F.M.), Neurometabolic Clinical Research Group, Paris, France
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21
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Yelam A, Nagarajan E, Chuquilin M, Govindarajan R. Leucoencephalopathy with brain stem and spinal cord involvement and lactate elevation: a novel mutation in the DARS2 gene. BMJ Case Rep 2019; 12:12/1/bcr-2018-227755. [PMID: 30635318 DOI: 10.1136/bcr-2018-227755] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Leucoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a very rare autosomal recessive, slowly progressive neurological disorder characterised by distinctive clinical findings including cerebellar, pyramidal and dorsal column dysfunction. This is caused by a mutation in the DARS2 gene, which encodes mitochondrial aspartyl-tRNA synthetase. MRI shows distinctive abnormalities in the cerebral white matter and specific brain stem and spinal cord tracts. Here, we present a case of LBSL, with a novel c.1192-2A>G mutation.
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Affiliation(s)
- Anudeep Yelam
- Neurology, University of Missouri Health Care, Columbia, Missouri, USA
| | - Elanagan Nagarajan
- Neurology, Howard Hughes Medical Institute, School of Medicine, University of Missouri Columbia, Columbia, Missouri, USA
| | - Miguel Chuquilin
- Neurology, University of Florida College of Medicine, Gainesville, Florida, USA
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22
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González-Serrano LE, Karim L, Pierre F, Schwenzer H, Rötig A, Munnich A, Sissler M. Three human aminoacyl-tRNA synthetases have distinct sub-mitochondrial localizations that are unaffected by disease-associated mutations. J Biol Chem 2018; 293:13604-13615. [PMID: 30006346 PMCID: PMC6120215 DOI: 10.1074/jbc.ra118.003400] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/12/2018] [Indexed: 01/04/2023] Open
Abstract
Human mitochondrial aminoacyl-tRNA synthetases (mt-aaRSs) are key enzymes in the mitochondrial protein translation system and catalyze the charging of amino acids on their cognate tRNAs. Mutations in their nuclear genes are associated with pathologies having a broad spectrum of clinical phenotypes, but with no clear molecular mechanism(s). For example, mutations in the nuclear genes encoding mt-AspRS and mt-ArgRS are correlated with the moderate neurodegenerative disorder leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) and with the severe neurodevelopmental disorder pontocerebellar hypoplasia type 6 (PCH6), respectively. Previous studies have shown no or only minor impacts of these mutations on the canonical properties of these enzymes, indicating that the role of the mt-aaRSs in protein synthesis is mostly not affected by these mutations, but their effects on the mitochondrial localizations of aaRSs remain unclear. Here, we demonstrate that three human aaRSs, mt-AspRS, mt-ArgRS, and LysRS, each have a specific sub-mitochondrial distribution, with mt-ArgRS being exclusively localized in the membrane, LysRS exclusively in the soluble fraction, and mt-AspRS being present in both. Chemical treatments revealed that mt-AspRs is anchored in the mitochondrial membrane through electrostatic interactions, whereas mt-ArgRS uses hydrophobic interactions. We also report that novel mutations in mt-AspRS and mt-ArgRS genes from individuals with LBSL and PCH6, respectively, had no significant impact on the mitochondrial localizations of mt-AspRS and mt-ArgRS. The variable sub-mitochondrial locations for these three mt-aaRSs strongly suggest the existence of additional enzyme properties, requiring further investigation to unravel the mechanisms underlying the two neurodegenerative disorders.
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Affiliation(s)
- Ligia Elena González-Serrano
- From the Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67084 Strasbourg, France and
| | - Loukmane Karim
- From the Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67084 Strasbourg, France and
| | - Florian Pierre
- From the Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67084 Strasbourg, France and
| | - Hagen Schwenzer
- From the Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67084 Strasbourg, France and
| | - Agnès Rötig
- the INSERM UMR 1163, Laboratory of Genetics of Mitochondrial Disorders, Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, F-75015 Paris, France
| | - Arnold Munnich
- the INSERM UMR 1163, Laboratory of Genetics of Mitochondrial Disorders, Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, F-75015 Paris, France
| | - Marie Sissler
- From the Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67084 Strasbourg, France and
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23
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Aradjanski M, Dogan SA, Lotter S, Wang S, Hermans S, Wibom R, Rugarli E, Trifunovic A. DARS2 protects against neuroinflammation and apoptotic neuronal loss, but is dispensable for myelin producing cells. Hum Mol Genet 2018; 26:4181-4189. [PMID: 28985337 DOI: 10.1093/hmg/ddx307] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/26/2017] [Indexed: 12/14/2022] Open
Abstract
Although mitochondria are ubiquitous, each mitochondrial disease has surprisingly distinctly different pattern of tissue and organ involvement. Congruently, mutations in genes encoding for different mitochondrial tRNA synthetases result in the development of a very flamboyant group of diseases. Mutations in some of these genes, including aspartyl-tRNA synthetase (DARS2), lead to the onset of a white matter disease-leukoencephalopathy with brainstem and spinal cord involvement, and lactate elevation (LBSL) characterized by progressive spastic ataxia and characteristic leukoencephalopathy signature with multiple long-tract involvements. Puzzled by the white matter disease phenotypes caused by DARS2 deficiency when numerous other mutations in the genes encoding proteins involved in mitochondrial translation have a detrimental effect predominantly on neurons, we generated transgenic mice in which DARS2 was specifically depleted in forebrain-hippocampal neurons or myelin-producing cells. Our results now provide the first evidence that loss of DARS2 in adult neurons leads to strong mitochondrial dysfunction and progressive loss of cells. In contrast, myelin-producing cells seem to be resistant to cell death induced by DARS2 depletion despite robust respiratory chain deficiency arguing that LBSL might originate from the primary neuronal and axonal defect. Remarkably, our results also suggest a role for early neuroinflammation in the disease progression, highlighting the possibility for therapeutic interventions of this process.
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Affiliation(s)
- Marijana Aradjanski
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Sukru Anil Dogan
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Stephan Lotter
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Shuaiyu Wang
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.,Institute for Genetics, University of Cologne, 50674 Cologne, Germany
| | - Steffen Hermans
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany
| | - Rolf Wibom
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177 Stockholm, Sweden
| | - Elena Rugarli
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.,Institute for Genetics, University of Cologne, 50674 Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Aleksandra Trifunovic
- Institute for Mitochondrial Diseases and Aging, Medical Faculty, University of Cologne, 50931 Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, 50931 Cologne, Germany
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Mimura I, Hirakawa Y, Kanki Y, Kushida N, Nakaki R, Suzuki Y, Tanaka T, Aburatani H, Nangaku M. Novel lnc RNA regulated by HIF-1 inhibits apoptotic cell death in the renal tubular epithelial cells under hypoxia. Physiol Rep 2018; 5:5/8/e13203. [PMID: 28420760 PMCID: PMC5408278 DOI: 10.14814/phy2.13203] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 02/15/2017] [Indexed: 12/22/2022] Open
Abstract
Chronic tubulointerstitial hypoxia plays an important role as the final common pathway to end-stage renal disease. HIF-1 (hypoxia-inducible factor-1) is a master transcriptional factor under hypoxia, regulating downstream target genes. Genome-wide analysis of HIF-1 binding sites using high-throughput sequencers has clarified various kinds of downstream targets and made it possible to demonstrate the novel roles of HIF-1. Our aim of this study is to identify novel HIF-1 downstream epigenetic targets which may play important roles in the kidney. Immortalized tubular cell lines (HK2; human kidney-2) and primary cultured cells (RPTEC; renal proximal tubular cell lines) were exposed to 1% hypoxia for 24-72 h. We performed RNA-seq to clarify the expression of mRNA and long non-coding RNA (lncRNA). We also examined ChIP-seq to identify HIF-1 binding sites under hypoxia. RNA-seq identified 44 lncRNAs which are up-regulated under hypoxic condition in both cells. ChIP-seq analysis demonstrated that HIF-1 also binds to the lncRNAs under hypoxia. The expression of novel lncRNA, DARS-AS1 (aspartyl-tRNA synthetase anti-sense 1), is up-regulated only under hypoxia and HIF-1 binds to its promoter region, which includes two hypoxia-responsive elements. Its expression is also up-regulated with cobalt chloride exposure, while it is not under hypoxia when HIF-1 is knocked down by siRNA To clarify the biological roles of DARS-AS1, we measured the activity of caspase 3/7 using anti-sense oligo of DARS-AS1. Knockdown of DARS-AS1 deteriorated apoptotic cell death. In conclusion, we identified the novel lncRNAs regulated by HIF-1 under hypoxia and clarified that DARS-AS1 plays an important role in inhibiting apoptotic cell death in renal tubular cells.
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Affiliation(s)
- Imari Mimura
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yosuke Hirakawa
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yasuharu Kanki
- Isotope Science Center, The University of Tokyo., Tokyo, Japan
| | - Natsuki Kushida
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Ryo Nakaki
- Division of GenomeScience, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Yutaka Suzuki
- Graduate School of Frontier Sciences, The University of Tokyo, Tokyo, Japan
| | - Tetsuhiro Tanaka
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Aburatani
- Division of GenomeScience, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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van der Knaap MS, Bugiani M. Leukodystrophies: a proposed classification system based on pathological changes and pathogenetic mechanisms. Acta Neuropathol 2017; 134:351-382. [PMID: 28638987 PMCID: PMC5563342 DOI: 10.1007/s00401-017-1739-1] [Citation(s) in RCA: 216] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/06/2017] [Accepted: 06/06/2017] [Indexed: 12/29/2022]
Abstract
Leukodystrophies are genetically determined disorders characterized by the selective involvement of the central nervous system white matter. Onset may be at any age, from prenatal life to senescence. Many leukodystrophies are degenerative in nature, but some only impair white matter function. The clinical course is mostly progressive, but may also be static or even improving with time. Progressive leukodystrophies are often fatal, and no curative treatment is known. The last decade has witnessed a tremendous increase in the number of defined leukodystrophies also owing to a diagnostic approach combining magnetic resonance imaging pattern recognition and next generation sequencing. Knowledge on white matter physiology and pathology has also dramatically built up. This led to the recognition that only few leukodystrophies are due to mutations in myelin- or oligodendrocyte-specific genes, and many are rather caused by defects in other white matter structural components, including astrocytes, microglia, axons and blood vessels. We here propose a novel classification of leukodystrophies that takes into account the primary involvement of any white matter component. Categories in this classification are the myelin disorders due to a primary defect in oligodendrocytes or myelin (hypomyelinating and demyelinating leukodystrophies, leukodystrophies with myelin vacuolization); astrocytopathies; leuko-axonopathies; microgliopathies; and leuko-vasculopathies. Following this classification, we illustrate the neuropathology and disease mechanisms of some leukodystrophies taken as example for each category. Some leukodystrophies fall into more than one category. Given the complex molecular and cellular interplay underlying white matter pathology, recognition of the cellular pathology behind a disease becomes crucial in addressing possible treatment strategies.
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Affiliation(s)
- Marjo S van der Knaap
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands
- Department of Functional Genomics, Centre for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, VU University, Amsterdam, The Netherlands
| | - Marianna Bugiani
- Department of Pediatrics/Child Neurology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands.
- Department of Pathology, VU University Medical Centre, Amsterdam Neuroscience, Amsterdam, The Netherlands.
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26
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Sissler M, González-Serrano LE, Westhof E. Recent Advances in Mitochondrial Aminoacyl-tRNA Synthetases and Disease. Trends Mol Med 2017; 23:693-708. [DOI: 10.1016/j.molmed.2017.06.002] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/08/2017] [Accepted: 06/14/2017] [Indexed: 01/02/2023]
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Ognjenović J, Simonović M. Human aminoacyl-tRNA synthetases in diseases of the nervous system. RNA Biol 2017; 15:623-634. [PMID: 28534666 PMCID: PMC6103678 DOI: 10.1080/15476286.2017.1330245] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 05/05/2017] [Accepted: 05/10/2017] [Indexed: 12/21/2022] Open
Abstract
Aminoacyl-tRNA synthetases (AaRSs) are ubiquitously expressed enzymes that ensure accurate translation of the genetic information into functional proteins. These enzymes also execute a variety of non-canonical functions that are significant for regulation of diverse cellular processes and that reside outside the realm of protein synthesis. Associations between faults in AaRS-mediated processes and human diseases have been long recognized. Most recent research findings strongly argue that 10 cytosolic and 14 mitochondrial AaRSs are implicated in some form of pathology of the human nervous system. The advent of modern whole-exome sequencing makes it all but certain that similar associations between the remaining 15 ARS genes and neurologic illnesses will be defined in future. It is not surprising that an intense scientific debate about the role of translational machinery, in general, and AaRSs, in particular, in the development and maintenance of the healthy human neural cell types and the brain is sparked. Herein, we summarize the current knowledge about causative links between mutations in human AaRSs and diseases of the nervous system and briefly discuss future directions.
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Affiliation(s)
- Jana Ognjenović
- Department of Biochemistry and Molecular Genetics, College of Medicine, The University of Illinois at Chicago, Chicago, IL, USA
| | - Miljan Simonović
- Department of Biochemistry and Molecular Genetics, College of Medicine, The University of Illinois at Chicago, Chicago, IL, USA
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Mendes MI, Smith DE, Pop A, Lennertz P, Fernandez Ojeda MR, Kanhai WA, van Dooren SJ, Anikster Y, Barić I, Boelen C, Campistol J, de Boer L, Kariminejad A, Kayserili H, Roubertie A, Verbruggen KT, Vianey-Saban C, Williams M, Salomons GS. Clinically Distinct Phenotypes of Canavan Disease Correlate with Residual Aspartoacylase Enzyme Activity. Hum Mutat 2017; 38:524-531. [PMID: 28101991 PMCID: PMC5412892 DOI: 10.1002/humu.23181] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/16/2017] [Indexed: 11/29/2022]
Abstract
We describe 14 patients with 12 novel missense mutations in ASPA, the gene causing Canavan disease (CD). We developed a method to study the effect of these 12 variants on the function of aspartoacylase—the hydrolysis of N‐acetyl‐l‐aspartic acid (NAA) to aspartate and acetate. The wild‐type ASPA open reading frame (ORF) and the ORFs containing each of the variants were transfected into HEK293 cells. Enzyme activity was determined by incubating cell lysates with NAA and measuring the released aspartic acid by LC–MS/MS. Clinical data were obtained for 11 patients by means of questionnaires. Four patients presented with a non‐typical clinical picture or with the milder form of CD, whereas seven presented with severe CD. The mutations found in the mild patients corresponded to the variants with the highest residual enzyme activities, suggesting that this assay can help evaluate unknown variants found in patients with atypical presentation. We have detected a correlation between clinical presentation, enzyme activity, and genotype for CD.
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Affiliation(s)
- Marisa I Mendes
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Desirée Ec Smith
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Ana Pop
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Pascal Lennertz
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Matilde R Fernandez Ojeda
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Warsha A Kanhai
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Silvy Jm van Dooren
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Yair Anikster
- Edmond and Lily Safra Children's Hospital, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Israel
| | - Ivo Barić
- Department of Pediatrics, University Hospital Center Zagreb & University of Zagreb, School of Medicine, Zagreb, Croatia
| | - Caroline Boelen
- Department of Pediatrics, Admiraal De Ruyter Ziekenhuis, Goes, Zeeland, The Netherlands
| | - Jaime Campistol
- Neurology Department, CIBERER ISCIII, Hospital Sant Joan de Deu, University of Barcelona, Barcelona, Spain
| | - Lonneke de Boer
- Department of pediatrics, metabolic diseases, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Hulya Kayserili
- Medical Genetics Department, Koç University School of Medicine (KUSOM), Istanbul, Turkey
| | - Agathe Roubertie
- Département de Neuropédiatrie, Hopital Gui de Chauliac, Montpellier, Languedoc-Roussillon, France.,INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Krijn T Verbruggen
- Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Christine Vianey-Saban
- Centre de Biologie et de Pathologie Est CHU de Lyon, Service Maladies Héréditaires du Métabolisme et Dépistage Néonatal, Lyon, France
| | - Monique Williams
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Gajja S Salomons
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, The Netherlands
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Linnankivi T, Neupane N, Richter U, Isohanni P, Tyynismaa H. Splicing Defect in Mitochondrial Seryl-tRNA Synthetase Gene Causes Progressive Spastic Paresis Instead of HUPRA Syndrome. Hum Mutat 2016; 37:884-8. [PMID: 27279129 DOI: 10.1002/humu.23021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/23/2016] [Indexed: 01/08/2023]
Abstract
Mitochondrial aminoacyl-tRNA synthetases are an important group of disease genes typically underlying either a disorder affecting an isolated tissue or a distinct syndrome. Missense mutations in the mitochondrial seryl-tRNA synthetase gene, SARS2, have been identified in HUPRA syndrome (hyperuricemia, pulmonary hypertension, renal failure in infancy, and alkalosis). We report here a homozygous splicing mutation in SARS2 in a patient with progressive spastic paresis. We show that the mutation leads to diminished levels of the synthetase in patient's fibroblasts. This has a destabilizing effect on the tRNASer(AGY) isoacceptor, but to a lesser degree than in HUPRA syndrome patients. tRNASer(UCN) is largely unaffected in both phenotypes. In conclusion, the level of tRNASer(AGY) instability may be a factor in determining tissue manifestation in patients with SARS2 mutations. This finding exemplifies the sensitivity of the nervous system to partially reduced aminoacylation, which is sufficient in other tissues to maintain respiratory chain function.
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Affiliation(s)
- Tarja Linnankivi
- Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Nirajan Neupane
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Uwe Richter
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Pirjo Isohanni
- Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
| | - Henna Tyynismaa
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
- Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
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30
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Sauter C, Lorber B, Gaudry A, Karim L, Schwenzer H, Wien F, Roblin P, Florentz C, Sissler M. Neurodegenerative disease-associated mutants of a human mitochondrial aminoacyl-tRNA synthetase present individual molecular signatures. Sci Rep 2015; 5:17332. [PMID: 26620921 PMCID: PMC4664897 DOI: 10.1038/srep17332] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 10/29/2015] [Indexed: 12/03/2022] Open
Abstract
Mutations in human mitochondrial aminoacyl-tRNA synthetases are associated with a variety of neurodegenerative disorders. The effects of these mutations on the structure and function of the enzymes remain to be established. Here, we investigate six mutants of the aspartyl-tRNA synthetase correlated with leukoencephalopathies. Our integrated strategy, combining an ensemble of biochemical and biophysical approaches, reveals that mutants are diversely affected with respect to their solubility in cellular extracts and stability in solution, but not in architecture. Mutations with mild effects on solubility occur in patients as allelic combinations whereas those with strong effects on solubility or on aminoacylation are necessarily associated with a partially functional allele. The fact that all mutations show individual molecular and cellular signatures and affect amino acids only conserved in mammals, points towards an alternative function besides aminoacylation.
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Affiliation(s)
- Claude Sauter
- Architecture et Réactivité de l’ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France
| | - Bernard Lorber
- Architecture et Réactivité de l’ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France
| | - Agnès Gaudry
- Architecture et Réactivité de l’ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France
| | - Loukmane Karim
- Architecture et Réactivité de l’ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France
| | - Hagen Schwenzer
- Architecture et Réactivité de l’ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France
| | - Frank Wien
- Synchrotron SOLEIL, L’Orme des Merisiers Saint Aubin, 91410 Gif-sur-Yvette, France
| | - Pierre Roblin
- Synchrotron SOLEIL, L’Orme des Merisiers Saint Aubin, 91410 Gif-sur-Yvette, France
- URBIA-Nantes, INRA Centre de Nantes, 60 rue de la Géraudière, 44316 Nantes, France
| | - Catherine Florentz
- Architecture et Réactivité de l’ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France
| | - Marie Sissler
- Architecture et Réactivité de l’ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084 STRASBOURG Cedex, France
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Biancheri R, Lamantea E, Severino M, Diodato D, Pedemonte M, Cassandrini D, Ploederl A, Trucco F, Fiorillo C, Minetti C, Santorelli FM, Zeviani M, Bruno C. Expanding the Clinical and Magnetic Resonance Spectrum of Leukoencephalopathy with Thalamus and Brainstem Involvement and High Lactate (LTBL) in a Patient Harboring a Novel EARS2 Mutation. JIMD Rep 2015; 23:85-9. [PMID: 25854774 PMCID: PMC4484897 DOI: 10.1007/8904_2015_434] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 02/23/2015] [Accepted: 03/06/2015] [Indexed: 02/09/2023] Open
Abstract
Leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) is a novel mitochondrial disease caused by mutations in EARS2, which encodes the mitochondrial glutamyl-tRNA synthetase (mtGluRS). A distinctive brain MRI pattern is the hallmark of the disease.A 6-year-old boy presented at 3 months with feeding difficulties and muscle hypotonia. Brain MRI, at 8 months, showed hyperintensity of the deep cerebral and cerebellar white matter, thalamus, basal ganglia, brainstem, and thin corpus callosum. From the second year of life onward, the child reported global clinical improvement, parallel to partial resolution of brain MRI pattern. However, the last neuroimaging assessment revealed novel lesions within the left caudate and pallidum nuclei. DNA genomic sequencing analysis identified a novel EARS2 mutation.This case expands the clinical and neuroradiological phenotype of LTBL presenting intermediate clinical manifestations between the severe and milder forms of the disease and previously unreported brain MRI features.
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Affiliation(s)
- Roberta Biancheri
- />Child Neurology and Psychiatry, Istituto Giannina Gaslini, Genoa, Italy
| | - Eleonora Lamantea
- />Unit of Molecular Neurogenetics Pierfranco and Luisa Mariani Center for the Study of Mitochondrial Disorders in Children, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | | | - Daria Diodato
- />Unit of Molecular Neurogenetics Pierfranco and Luisa Mariani Center for the Study of Mitochondrial Disorders in Children, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Marina Pedemonte
- />Pediatric Neurology Unit, Istituto Giannina Gaslini, Genoa, Italy
| | - Denise Cassandrini
- />Neuromuscular and Molecular Medicine Unit, IRCCS Stella Maris, Pisa, Italy
| | - Alexandra Ploederl
- />Child Neurology and Psychiatry, Istituto Giannina Gaslini, Genoa, Italy
| | - Federica Trucco
- />Pediatric Neurology Unit, Istituto Giannina Gaslini, Genoa, Italy
| | - Chiara Fiorillo
- />Neuromuscular and Molecular Medicine Unit, IRCCS Stella Maris, Pisa, Italy
| | - Carlo Minetti
- />Pediatric Neurology Unit, Istituto Giannina Gaslini, Genoa, Italy
| | | | - Massimo Zeviani
- />Unit of Molecular Neurogenetics Pierfranco and Luisa Mariani Center for the Study of Mitochondrial Disorders in Children, Fondazione IRCCS Istituto Neurologico “Carlo Besta”, Milan, Italy
| | - Claudio Bruno
- />Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto Giannina Gaslini, Genoa, Italy
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Ahola S, Isohanni P, Euro L, Brilhante V, Palotie A, Pihko H, Lönnqvist T, Lehtonen T, Laine J, Tyynismaa H, Suomalainen A. Mitochondrial EFTs defects in juvenile-onset Leigh disease, ataxia, neuropathy, and optic atrophy. Neurology 2014; 83:743-51. [PMID: 25037205 DOI: 10.1212/wnl.0000000000000716] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE We report novel defects of mitochondrial translation elongation factor Ts (EFTs), with high carrier frequency in Finland and expand the manifestations of this disease group from infantile cardiomyopathy to juvenile neuropathy/encephalopathy disorders. METHODS DNA analysis, whole-exome analysis, protein biochemistry, and protein modeling. RESULTS We used whole-exome sequencing to find the genetic cause of infantile-onset mitochondrial cardiomyopathy, progressing to juvenile-onset Leigh syndrome, neuropathy, and optic atrophy in 2 siblings. We found novel compound heterozygous mutations, c.944G>A [p.C315Y] and c.856C>T [p.Q286X], in the TSFM gene encoding mitochondrial EFTs. The same p.Q286X variant was found as compound heterozygous with a splice site change in a patient from a second family, with juvenile-onset optic atrophy, peripheral neuropathy, and ataxia. Our molecular modeling predicted the coding-region mutations to cause protein instability, which was experimentally confirmed in cultured patient cells, with mitochondrial translation defect and lacking EFTs. Only a single TSFM mutation has been previously described in different populations, leading to an infantile fatal multisystem disorder with cardiomyopathy. Sequence data from 35,000 Finnish population controls indicated that the heterozygous carrier frequency of p.Q286X change was exceptionally high in Finland, 1:80, but no homozygotes were found in the population, in our mitochondrial disease patient collection, or in an intrauterine fetal death material, suggesting early developmental lethality of the homozygotes. CONCLUSIONS We show that in addition to early-onset cardiomyopathy, TSFM mutations should be considered in childhood and juvenile encephalopathies with optic and/or peripheral neuropathy, ataxia, or Leigh disease.
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Affiliation(s)
- Sofia Ahola
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Pirjo Isohanni
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Liliya Euro
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Virginia Brilhante
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Aarno Palotie
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Helena Pihko
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Tuula Lönnqvist
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Tanita Lehtonen
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Jukka Laine
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Henna Tyynismaa
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland
| | - Anu Suomalainen
- From the Research Programs Unit, Molecular Neurology, Biomedicum Helsinki (S.A., P.I., L.E., V.B., H.T., A.S.), Institute for Molecular Medicine Finland (A.P.), Department of Medical Genetics, Haartman Institute (H.T.), and Neuroscience Center (A.S.), University of Helsinki; Department of Child Neurology, Children's Hospital (P.I., H.P., T. Lönnqvist), and Department of Neurology (A.S.), Helsinki University Central Hospital, Finland; Analytic and Translational Genetics Unit, Department of Medicine (A.P.), and Psychiatric & Neurodevelopmental Genetics Unit, Department of Psychiatry (A.P.), Massachusetts General Hospital, Boston; Program in Medical and Population Genetics (A.P.), Broad Institute of MIT and Harvard, Cambridge, MA; and Department of Pathology (T. Lehtonen, J.L.), University of Turku, Finland.
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Abbott JA, Francklyn CS, Robey-Bond SM. Transfer RNA and human disease. Front Genet 2014; 5:158. [PMID: 24917879 PMCID: PMC4042891 DOI: 10.3389/fgene.2014.00158] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/14/2014] [Indexed: 12/25/2022] Open
Abstract
Pathological mutations in tRNA genes and tRNA processing enzymes are numerous and result in very complicated clinical phenotypes. Mitochondrial tRNA (mt-tRNA) genes are “hotspots” for pathological mutations and over 200 mt-tRNA mutations have been linked to various disease states. Often these mutations prevent tRNA aminoacylation. Disrupting this primary function affects protein synthesis and the expression, folding, and function of oxidative phosphorylation enzymes. Mitochondrial tRNA mutations manifest in a wide panoply of diseases related to cellular energetics, including COX deficiency (cytochrome C oxidase), mitochondrial myopathy, MERRF (Myoclonic Epilepsy with Ragged Red Fibers), and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). Diseases caused by mt-tRNA mutations can also affect very specific tissue types, as in the case of neurosensory non-syndromic hearing loss and pigmentary retinopathy, diabetes mellitus, and hypertrophic cardiomyopathy. Importantly, mitochondrial heteroplasmy plays a role in disease severity and age of onset as well. Not surprisingly, mutations in enzymes that modify cytoplasmic and mitochondrial tRNAs are also linked to a diverse range of clinical phenotypes. In addition to compromised aminoacylation of the tRNAs, mutated modifying enzymes can also impact tRNA expression and abundance, tRNA modifications, tRNA folding, and even tRNA maturation (e.g., splicing). Some of these pathological mutations in tRNAs and processing enzymes are likely to affect non-canonical tRNA functions, and contribute to the diseases without significantly impacting on translation. This chapter will review recent literature on the relation of mitochondrial and cytoplasmic tRNA, and enzymes that process tRNAs, to human disease. We explore the mechanisms involved in the clinical presentation of these various diseases with an emphasis on neurological disease.
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Affiliation(s)
- Jamie A Abbott
- Department of Biochemistry, College of Medicine, University of Vermont Burlington, VT, USA
| | | | - Susan M Robey-Bond
- Department of Biochemistry, College of Medicine, University of Vermont Burlington, VT, USA
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34
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van Berge L, Hamilton EM, Linnankivi T, Uziel G, Steenweg ME, Isohanni P, Wolf NI, Krägeloh-Mann I, Brautaset NJ, Andrews PI, de Jong BA, al Ghamdi M, van Wieringen WN, Tannous BA, Hulleman E, Würdinger T, van Berkel CGM, Polder E, Abbink TEM, Struys EA, Scheper GC, van der Knaap MS. Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation: clinical and genetic characterization and target for therapy. Brain 2014; 137:1019-29. [PMID: 24566671 DOI: 10.1093/brain/awu026] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Laura van Berge
- 1 Department of Child Neurology, VU University Medical Centre, Neuroscience Campus, Amsterdam, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
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The Mitochondrial Aminoacyl tRNA Synthetases: Genes and Syndromes. Int J Cell Biol 2014; 2014:787956. [PMID: 24639874 PMCID: PMC3932222 DOI: 10.1155/2014/787956] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/01/2013] [Indexed: 02/05/2023] Open
Abstract
Mitochondrial respiratory chain (RC) disorders are a group of genetically and clinically heterogeneous diseases. This is because protein components of the RC are encoded by both mitochondrial and nuclear genomes and are essential in all cells. In addition, the biogenesis and maintenance of mitochondria, including mitochondrial DNA (mtDNA) replication, transcription, and translation, require nuclear-encoded genes. In the past decade, a growing number of syndromes associated with dysfunction of mtDNA translation have been reported. This paper reviews the current knowledge of mutations affecting mitochondrial aminoacyl tRNAs synthetases and their role in the pathogenic mechanisms underlying the different clinical presentations.
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Martikainen MH, Ellfolk U, Majamaa K. Impaired information-processing speed and working memory in leukoencephalopathy with brainstem and spinal cord involvement and elevated lactate (LBSL) and DARS2 mutations: a report of three adult patients. J Neurol 2013; 260:2078-83. [PMID: 23652419 DOI: 10.1007/s00415-013-6940-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 04/22/2013] [Accepted: 04/25/2013] [Indexed: 12/01/2022]
Abstract
Leukoencephalopathy with brainstem and spinal cord involvement and elevated lactate (LBSL) is clinically characterized by progressive pyramidal and cerebellar dysfunction, dorsal column dysfunction and sometimes with axonal neuropathy. Magnetic resonance imaging of brain and the spinal cord reveals characteristic findings. LBSL is caused by mutations in the DARS2 gene that encodes the mitochondrial aspartyl-tRNA synthetase. The presentation and clinical course of LBSL is not uniform, and there is lack of longitudinal data on these patients. In addition, the existing data on the prevalence and characteristics of cognitive abnormalities in patients with LBSL are scarce and somewhat conflicting. Here we report long-term data of neurological and cognitive functioning in three non-related adult patients with LBSL. Cognitive impairment seems to be common among patients with LBSL and DARS2 mutations. The cognitive profile in LBSL shares similarities with that reported in multiple sclerosis, as information-processing speed and working memory are especially affected. In addition, our results and the previously reported carrier frequencies of common pathogenic DARS2 mutations suggest that LBSL may be underdiagnosed in the population.
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Affiliation(s)
- Mika H Martikainen
- Division of Clinical Neurosciences, University of Turku and Turku University Hospital, Kiinamyllynkatu 4-8, 20520 Turku, Finland.
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Taft RJ, Vanderver A, Leventer RJ, Damiani SA, Simons C, Grimmond SM, Miller D, Schmidt J, Lockhart PJ, Pope K, Ru K, Crawford J, Rosser T, de Coo IFM, Juneja M, Verma IC, Prabhakar P, Blaser S, Raiman J, Pouwels PJW, Bevova MR, Abbink TEM, van der Knaap MS, Wolf NI. Mutations in DARS cause hypomyelination with brain stem and spinal cord involvement and leg spasticity. Am J Hum Genet 2013; 92:774-80. [PMID: 23643384 DOI: 10.1016/j.ajhg.2013.04.006] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/01/2013] [Accepted: 04/08/2013] [Indexed: 02/03/2023] Open
Abstract
Inherited white-matter disorders are a broad class of diseases for which treatment and classification are both challenging. Indeed, nearly half of the children presenting with a leukoencephalopathy remain without a specific diagnosis. Here, we report on the application of high-throughput genome and exome sequencing to a cohort of ten individuals with a leukoencephalopathy of unknown etiology and clinically characterized by hypomyelination with brain stem and spinal cord involvement and leg spasticity (HBSL), as well as the identification of compound-heterozygous and homozygous mutations in cytoplasmic aspartyl-tRNA synthetase (DARS). These mutations cause nonsynonymous changes to seven highly conserved amino acids, five of which are unchanged between yeast and man, in the DARS C-terminal lobe adjacent to, or within, the active-site pocket. Intriguingly, HBSL bears a striking resemblance to leukoencephalopathy with brain stem and spinal cord involvement and elevated lactate (LBSL), which is caused by mutations in the mitochondria-specific DARS2, suggesting that these two diseases might share a common underlying molecular pathology. These findings add to the growing body of evidence that mutations in tRNA synthetases can cause a broad range of neurologic disorders.
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Affiliation(s)
- Ryan J Taft
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Queensland 4072, Australia.
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Konovalova S, Tyynismaa H. Mitochondrial aminoacyl-tRNA synthetases in human disease. Mol Genet Metab 2013; 108:206-11. [PMID: 23433712 DOI: 10.1016/j.ymgme.2013.01.010] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/20/2013] [Accepted: 01/20/2013] [Indexed: 01/15/2023]
Abstract
Mitochondrial aminoacyl-tRNA synthetases (mtARSs) are essential in the process of transferring genetic information from mitochondrial DNA to the complexes of the oxidative phosphorylation system. These synthetases perform an integral step in the initiation of mitochondrial protein synthesis by charging tRNAs with their cognate amino acids. All mtARSs are encoded by nuclear genes, nine of which have recently been described as disease genes for mitochondrial disorders. Unexpectedly, the clinical presentations of these diseases are highly specific to the affected synthetase. Encephalopathy is the most common manifestation but again with gene-specific outcomes. Other clinical presentations include myopathy with anemia, cardiomyopathy, tubulopathy and hearing loss with female ovarian dysgenesis. Here we review the described mutation types and the associated patient phenotypes. The identified mutation spectrum suggests that only mutation types that allow some residual tRNA-charging activity can result in the described mtARS diseases but the molecular mechanisms behind the selective tissue involvement are not currently understood.
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Affiliation(s)
- Svetlana Konovalova
- Research Programs Unit, Molecular Neurology, Biomedicum Helsinki and Department of Medical Genetics, Haartman Institute, University of Helsinki, 00014 Helsinki, Finland
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Hirschvogel K, Matiasek K, Flatz K, Drögemüller M, Drögemüller C, Reiner B, Fischer A. Magnetic resonance imaging and genetic investigation of a case of Rottweiler leukoencephalomyelopathy. BMC Vet Res 2013; 9:57. [PMID: 23531239 PMCID: PMC3614464 DOI: 10.1186/1746-6148-9-57] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Accepted: 03/14/2013] [Indexed: 11/12/2022] Open
Abstract
Background Leukoencephalomyelopathy is an inherited neurodegenerative disorder that affects the white matter of the spinal cord and brain and is known to occur in the Rottweiler breed. Due to the lack of a genetic test for this disorder, post mortem neuropathological examinations are required to confirm the diagnosis. Leukoencephalopathy with brain stem and spinal cord involvement and elevated lactate levels is a rare, autosomal recessive disorder in humans that was recently described to have clinical features and magnetic resonance imaging (MRI) findings that are similar to the histopathologic lesions that define leukoencephalomyelopathy in Rottweilers. Leukoencephalopathy with brain stem and spinal cord involvement is caused by mutations in the DARS2 gene, which encodes a mitochondrial aspartyl-tRNA synthetase. The objective of this case report is to present the results of MRI and candidate gene analysis of a case of Rottweiler leukoencephalomyelopathy to investigate the hypothesis that leukoencephalomyelopathy in Rottweilers could serve as an animal model of human leukoencephalopathy with brain stem and spinal cord involvement. Case presentation A two-and-a-half-year-old male purebred Rottweiler was evaluated for generalised progressive ataxia with hypermetria that was most evident in the thoracic limbs. MRI (T2-weighted) demonstrated well-circumscribed hyperintense signals within both lateral funiculi that extended from the level of the first to the sixth cervical vertebral body. A neurodegenerative disorder was suspected based on the progressive clinical course and MRI findings, and Rottweiler leukoencephalomyelopathy was subsequently confirmed via histopathology. The DARS2 gene was investigated as a causative candidate, but a sequence analysis failed to identify any disease-associated variants in the DNA sequence. Conclusion It was concluded that MRI may aid in the pre-mortem diagnosis of suspected cases of leukoencephalomyelopathy. Genes other than DARS2 may be involved in Rottweiler leukoencephalomyelopathy and may also be relevant in human leukoencephalopathy with brain stem and spinal cord involvement.
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Affiliation(s)
- Katrin Hirschvogel
- Department of Veterinary Clinical Sciences Ludwig-Maximilians-Universitaet, Neurology Service, Clinic of Small Animal Medicine, Munich, Germany
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Pathogenic mutations causing LBSL affect mitochondrial aspartyl-tRNA synthetase in diverse ways. Biochem J 2013; 450:345-50. [PMID: 23216004 DOI: 10.1042/bj20121564] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The autosomal recessive white matter disorder LBSL (leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation) is caused by mutations in DARS2, coding for mtAspRS (mitochondrial aspartyl-tRNA synthetase). Generally, patients are compound heterozygous for mutations in DARS2. Many different mutations have been identified in patients, including several missense mutations. In the present study, we have examined the effects of missense mutations found in LBSL patients on the expression, enzyme activity, localization and dimerization of mtAspRS, which is important for understanding the cellular defect underlying the pathogenesis of the disease. Nine different missense mutations were analysed and were shown to have various effects on mtAspRS properties. Several mutations have a direct effect on the catalytic activity of the enzyme; others have an effect on protein expression or dimerization. Most mutations have a clear impact on at least one of the properties of mtAspRS studied, probably resulting in a small contribution of the missense variants to the mitochondrial aspartylation activity in the cell.
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Schwenzer H, Zoll J, Florentz C, Sissler M. Pathogenic implications of human mitochondrial aminoacyl-tRNA synthetases. Top Curr Chem (Cham) 2013; 344:247-92. [PMID: 23824528 DOI: 10.1007/128_2013_457] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mitochondria are considered as the powerhouse of eukaryotic cells. They host several central metabolic processes fueling the oxidative phosphorylation pathway (OXPHOS) that produces ATP from its precursors ADP and inorganic phosphate Pi (PPi). The respiratory chain complexes responsible for the OXPHOS pathway are formed from complementary sets of protein subunits encoded by the nuclear genome and the mitochondrial genome, respectively. The expression of the mitochondrial genome requires a specific and fully active translation machinery from which aminoacyl-tRNA synthetases (aaRSs) are key actors. Whilst the macromolecules involved in mammalian mitochondrial translation have been under investigation for many years, there has been an explosion of interest in human mitochondrial aaRSs (mt-aaRSs) since the discovery of a large (and growing) number of mutations in these genes that are linked to a variety of neurodegenerative disorders. Herein we will review the present knowledge on mt-aaRSs in terms of their biogenesis, their connection to mitochondrial respiration, i.e., the respiratory chain (RC) complexes, and to the mitochondrial translation machinery. The pathology-related mutations detected so far are described, with special attention given to their impact on mt-aaRSs biogenesis, functioning, and/or subsequent activities. The collected data to date shed light on the diverse routes that are linking primary molecular possible impact of a mutation to its phenotypic expression. It is envisioned that a variety of mechanisms, inside and outside the translation machinery, would play a role on the heterogeneous manifestations of mitochondrial disorders.
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Affiliation(s)
- Hagen Schwenzer
- Architecture et Réactivité de l'ARN, CNRS, Université de Strasbourg, IBMC, 15 rue René Descartes, 67084, Strasbourg Cedex, France,
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