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Danačíková Š, Straka B, Daněk J, Kořínek V, Otáhal J. In vitro human cell culture models in a bench-to-bedside approach to epilepsy. Epilepsia Open 2024; 9:865-890. [PMID: 38637998 PMCID: PMC11145627 DOI: 10.1002/epi4.12941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 03/05/2024] [Accepted: 03/31/2024] [Indexed: 04/20/2024] Open
Abstract
Epilepsy is the most common chronic neurological disease, affecting nearly 1%-2% of the world's population. Current pharmacological treatment and regimen adjustments are aimed at controlling seizures; however, they are ineffective in one-third of the patients. Although neuronal hyperexcitability was previously thought to be mainly due to ion channel alterations, current research has revealed other contributing molecular pathways, including processes involved in cellular signaling, energy metabolism, protein synthesis, axon guidance, inflammation, and others. Some forms of drug-resistant epilepsy are caused by genetic defects that constitute potential targets for precision therapy. Although such approaches are increasingly important, they are still in the early stages of development. This review aims to provide a summary of practical aspects of the employment of in vitro human cell culture models in epilepsy diagnosis, treatment, and research. First, we briefly summarize the genetic testing that may result in the detection of candidate pathogenic variants in genes involved in epilepsy pathogenesis. Consequently, we review existing in vitro cell models, including induced pluripotent stem cells and differentiated neuronal cells, providing their specific properties, validity, and employment in research pipelines. We cover two methodological approaches. The first approach involves the utilization of somatic cells directly obtained from individual patients, while the second approach entails the utilization of characterized cell lines. The models are evaluated in terms of their research and clinical benefits, relevance to the in vivo conditions, legal and ethical aspects, time and cost demands, and available published data. Despite the methodological, temporal, and financial demands of the reviewed models they possess high potential to be used as robust systems in routine testing of pathogenicity of detected variants in the near future and provide a solid experimental background for personalized therapy of genetic epilepsies. PLAIN LANGUAGE SUMMARY: Epilepsy affects millions worldwide, but current treatments fail for many patients. Beyond traditional ion channel alterations, various genetic factors contribute to the disorder's complexity. This review explores how in vitro human cell models, either from patients or from cell lines, can aid in understanding epilepsy's genetic roots and developing personalized therapies. While these models require further investigation, they offer hope for improved diagnosis and treatment of genetic forms of epilepsy.
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Affiliation(s)
- Šárka Danačíková
- Laboratory of Developmental EpileptologyInstitute of Physiology of the Czech Academy of SciencesPragueCzech Republic
- Department of Pathophysiology, Second Faculty of MedicineCharles UniversityPragueCzech Republic
- Laboratory of Cell and Developmental BiologyInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
- Department of Physiology, Faculty of ScienceCharles UniversityPragueCzech Republic
| | - Barbora Straka
- Neurogenetics Laboratory of the Department of Paediatric Neurology, Second Faculty of MedicineCharles University and Motol University Hospital, Full Member of the ERN EpiCAREPragueCzech Republic
| | - Jan Daněk
- Laboratory of Developmental EpileptologyInstitute of Physiology of the Czech Academy of SciencesPragueCzech Republic
| | - Vladimír Kořínek
- Laboratory of Cell and Developmental BiologyInstitute of Molecular Genetics of the Czech Academy of SciencesPragueCzech Republic
| | - Jakub Otáhal
- Laboratory of Developmental EpileptologyInstitute of Physiology of the Czech Academy of SciencesPragueCzech Republic
- Department of Pathophysiology, Second Faculty of MedicineCharles UniversityPragueCzech Republic
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Zhang X, Xiang F, Li D, Yang F, Yu S, Wang X. Adult-onset combined oxidative phosphorylation deficiency type 14 manifests as epileptic status: a new phenotype and literature review. BMC Neurol 2024; 24:15. [PMID: 38166857 PMCID: PMC10759640 DOI: 10.1186/s12883-023-03480-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Combined oxidative phosphorylation deficiency (COXPD) is a severe disorder with early onset and autosomal recessive inheritance, and has been divided into 51 types (COXPD1-COXPD51). COXPD14 is caused by a mutation in the FARS2 gene, which encodes mitochondrial phenylalanyl-tRNA synthetase (mt-PheRS), an enzyme that transfers phenylalanine to its cognate tRNA in mitochondria. Since the first case was reported in 2012, an increasing number of FARS2 variations have been subsequently identified, which present three main phenotypic manifestations: early onset epileptic encephalopathy, hereditary spastic paraplegia, and juvenile-onset epilepsy. To our knowledge, no adult cases have been reported in the literature. METHODS We report in detail a case of genetically confirmed COXPD14 and review the relevant literature. RESULTS Approximately 58 subjects with disease-causing variants of FARS2 have been reported, including 31 cases of early onset epileptic encephalopathy, 16 cases of hereditary spastic paraplegia, 3 cases of juvenile-onset epilepsy, and 8 cases of unknown phenotype. We report a case of autosomal recessive COXPD14 in an adult with status epilepticus as the only manifestation with a good prognosis, which is different from that in neonatal or infant patients reported in the literature. c.467C > T (p.T156M) has been previously reported, while c.119_120del (p.E40Vfs*87) is novel, and, both mutations are pathogenic. CONCLUSIONS This case of autosomal recessive COXPD14 in an adult only presented as status epilepticus, which is different from the patients reported previously. Our study expands the mutation spectrum of FARS2, and we tended to define the phenotypes based on the clinical manifestation rather than the age of onset.
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Affiliation(s)
- Xu Zhang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Feng Xiang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Desheng Li
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Fei Yang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Shengyuan Yu
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China
| | - Xiangqing Wang
- Department of Neurology, The First Medical Center of Chinese PLA General Hospital, 28# Fuxing Road, Beijing, People's Republic of China.
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Chen W, Rehsi P, Thompson K, Yeo M, Stals K, He L, Schimmel P, Chrzanowska-Lightowlers ZMA, Wakeling E, Taylor RW, Kuhle B. Clinical and molecular characterization of novel FARS2 variants causing neonatal mitochondrial disease. Mol Genet Metab 2023; 140:107657. [PMID: 37523899 DOI: 10.1016/j.ymgme.2023.107657] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/22/2023] [Accepted: 07/22/2023] [Indexed: 08/02/2023]
Abstract
FARS2 encodes the mitochondrial phenylalanyl-tRNA synthetase (mtPheRS), which is essential for charging mitochondrial (mt-) tRNAPhe with phenylalanine for use in intramitochondrial translation. Many biallelic, pathogenic FARS2 variants have been described previously, which are mostly associated with two distinct clinical phenotypes; an early onset epileptic mitochondrial encephalomyopathy or a later onset spastic paraplegia. In this study, we report on a patient who presented at 3 weeks of age with tachypnoea and poor feeding, which progressed to severe metabolic decompensation with lactic acidosis and seizure activity followed by death at 9 weeks of age. Rapid trio whole exome sequencing identified compound heterozygous FARS2 variants including a pathogenic exon 2 deletion on one allele and a rare missense variant (c.593G > T, p.(Arg198Leu)) on the other allele, necessitating further work to aid variant classification. Assessment of patient fibroblasts demonstrated severely decreased steady-state levels of mtPheRS, but no obvious defect in any components of the oxidative phosphorylation system. To investigate the potential pathogenicity of the missense variant, we determined its high-resolution crystal structure, demonstrating a local structural destabilization in the catalytic domain. Moreover, the R198L mutation reduced the thermal stability and impaired the enzymatic activity of mtPheRS due to a lower binding affinity for tRNAPhe and a slower turnover rate. Together these data confirm the pathogenicity of this FARS2 variant in causing early-onset mitochondrial epilepsy.
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Affiliation(s)
- Wenqian Chen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Preeya Rehsi
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Mildrid Yeo
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Karen Stals
- Exeter Genomics Laboratory, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Langping He
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne NE1 4LP, UK
| | - Paul Schimmel
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; The Scripps Florida Research Institute at the University of Florida, Jupiter, FL 33458, USA
| | - Zofia M A Chrzanowska-Lightowlers
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK
| | - Emma Wakeling
- North East Thames Regional Genetic Service, Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne NE1 4LP, UK.
| | - Bernhard Kuhle
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen 37073, Germany.
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Oswald SL, Steinbrücker K, Achleitner MT, Göschl E, Bittner RE, Schmidt WM, Tiefenthaler E, Hammerl E, Eisl A, Mayr D, Mayr JA, Wortmann SB. Treatment of Mitochondrial Phenylalanyl-tRNa-Synthetase Deficiency (FARS2) with Oral Phenylalanine. Neuropediatrics 2023; 54:351-355. [PMID: 36603837 DOI: 10.1055/a-2008-4230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE By loading transfer RNAs with their cognate amino acids, aminoacyl-tRNA synthetases (ARS) are essential for protein translation. Both cytosolic ARS1-deficiencies and mitochondrial ARS2 deficiencies can cause severe diseases. Amino acid supplementation has shown to positively influence the clinical course of four individuals with cytosolic ARS1 deficiencies. We hypothesize that this intervention could also benefit individuals with mitochondrial ARS2 deficiencies. METHODS This study was designed as a N-of-1 trial. Daily oral L-phenylalanine supplementation was used in a 3-year-old girl with FARS2 deficiency. A period without supplementation was implemented to discriminate the effects of treatment from age-related developments and continuing physiotherapy. Treatment effects were measured through a physiotherapeutic testing battery, including movement assessment battery for children, dynamic gait index, gross motor function measure 66, and quality of life questionnaires. RESULTS The individual showed clear improvement in all areas tested, especially in gross motor skills, movement abilities, and postural stability. In the period without supplementation, she lost newly acquired motor skills but regained these upon restarting supplementation. No adverse effects and good tolerance of treatment were observed. INTERPRETATION AND CONCLUSION Our positive results encourage further studies both on L-phenylalanine for other individuals with FARS2 deficiency and the exploration of this treatment rationale for other ARS2 deficiencies. Additionally, treatment costs were relatively low at 1.10 €/day.
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Affiliation(s)
- Susanne L Oswald
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | - Katja Steinbrücker
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | - Melanie T Achleitner
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | | | - Reginald E Bittner
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Wolfgang M Schmidt
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Elke Tiefenthaler
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | - Emma Hammerl
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | - Anna Eisl
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | - Doris Mayr
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | - Johannes A Mayr
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
| | - Saskia B Wortmann
- University Children's Hospital, Paracelsus Medical University (PMU) Salzburg, Salzburg, Austria
- Department of Pediatrics, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
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Kong LY, Wu YZ, Cheng RQ, Wang PH, Peng BW. Role of Mutations of Mitochondrial Aminoacyl-tRNA Synthetases Genes on Epileptogenesis. Mol Neurobiol 2023; 60:5482-5492. [PMID: 37316759 DOI: 10.1007/s12035-023-03429-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
Mitochondria are the structures in cells that are responsible for producing energy. They contain a specific translation unit for synthesizing mitochondria-encoded respiratory chain components: the mitochondrial DNA (mt DNA). Recently, a growing number of syndromes associated with the dysfunction of mt DNA translation have been reported. However, the functions of these diseases still need to be precise and thus attract much attention. Mitochondrial tRNAs (mt tRNAs) are encoded by mt DNA; they are the primary cause of mitochondrial dysfunction and are associated with a wide range of pathologies. Previous research has shown the role of mt tRNAs in the epileptic mechanism. This review will focus on the function of mt tRNA and the role of mitochondrial aminoacyl-tRNA synthetase (mt aaRS) in order to summarize some common relevant mutant genes of mt aaRS that cause epilepsy and the specific symptoms of the disease they cause.
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Affiliation(s)
- Ling-Yue Kong
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Yi-Ze Wu
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Run-Qi Cheng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Pei-Han Wang
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Bi-Wen Peng
- Department of Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, China.
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, School of Basic Medical Sciences, Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China.
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6
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Kalotay E, Klugmann M, Housley GD, Fröhlich D. Recessive aminoacyl-tRNA synthetase disorders: lessons learned from in vivo disease models. Front Neurosci 2023; 17:1182874. [PMID: 37274208 PMCID: PMC10234152 DOI: 10.3389/fnins.2023.1182874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 04/17/2023] [Indexed: 06/06/2023] Open
Abstract
Protein synthesis is a fundamental process that underpins almost every aspect of cellular functioning. Intriguingly, despite their common function, recessive mutations in aminoacyl-tRNA synthetases (ARSs), the family of enzymes that pair tRNA molecules with amino acids prior to translation on the ribosome, cause a diverse range of multi-system disorders that affect specific groups of tissues. Neurological development is impaired in most ARS-associated disorders. In addition to central nervous system defects, diseases caused by recessive mutations in cytosolic ARSs commonly affect the liver and lungs. Patients with biallelic mutations in mitochondrial ARSs often present with encephalopathies, with variable involvement of peripheral systems. Many of these disorders cause severe disability, and as understanding of their pathogenesis is currently limited, there are no effective treatments available. To address this, accurate in vivo models for most of the recessive ARS diseases are urgently needed. Here, we discuss approaches that have been taken to model recessive ARS diseases in vivo, highlighting some of the challenges that have arisen in this process, as well as key results obtained from these models. Further development and refinement of animal models is essential to facilitate a better understanding of the pathophysiology underlying recessive ARS diseases, and ultimately to enable development and testing of effective therapies.
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Affiliation(s)
- Elizabeth Kalotay
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
- Research Beyond Borders, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Gary D. Housley
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Dominik Fröhlich
- Translational Neuroscience Facility and Department of Physiology, School of Biomedical Sciences, University of New South Wales, Sydney, NSW, Australia
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7
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Kaplow IM, Lawler AJ, Schäffer DE, Srinivasan C, Sestili HH, Wirthlin ME, Phan BN, Prasad K, Brown AR, Zhang X, Foley K, Genereux DP, Karlsson EK, Lindblad-Toh K, Meyer WK, Pfenning AR, Andrews G, Armstrong JC, Bianchi M, Birren BW, Bredemeyer KR, Breit AM, Christmas MJ, Clawson H, Damas J, Di Palma F, Diekhans M, Dong MX, Eizirik E, Fan K, Fanter C, Foley NM, Forsberg-Nilsson K, Garcia CJ, Gatesy J, Gazal S, Genereux DP, Goodman L, Grimshaw J, Halsey MK, Harris AJ, Hickey G, Hiller M, Hindle AG, Hubley RM, Hughes GM, Johnson J, Juan D, Kaplow IM, Karlsson EK, Keough KC, Kirilenko B, Koepfli KP, Korstian JM, Kowalczyk A, Kozyrev SV, Lawler AJ, Lawless C, Lehmann T, Levesque DL, Lewin HA, Li X, Lind A, Lindblad-Toh K, Mackay-Smith A, Marinescu VD, Marques-Bonet T, Mason VC, Meadows JRS, Meyer WK, Moore JE, Moreira LR, Moreno-Santillan DD, Morrill KM, Muntané G, Murphy WJ, Navarro A, Nweeia M, Ortmann S, Osmanski A, Paten B, Paulat NS, Pfenning AR, Phan BN, Pollard KS, Pratt HE, Ray DA, Reilly SK, Rosen JR, Ruf I, Ryan L, Ryder OA, Sabeti PC, Schäffer DE, Serres A, Shapiro B, Smit AFA, Springer M, Srinivasan C, Steiner C, Storer JM, Sullivan KAM, Sullivan PF, Sundström E, Supple MA, Swofford R, Talbot JE, Teeling E, Turner-Maier J, Valenzuela A, Wagner F, Wallerman O, Wang C, Wang J, Weng Z, Wilder AP, Wirthlin ME, Xue JR, Zhang X. Relating enhancer genetic variation across mammals to complex phenotypes using machine learning. Science 2023; 380:eabm7993. [PMID: 37104615 DOI: 10.1126/science.abm7993] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Protein-coding differences between species often fail to explain phenotypic diversity, suggesting the involvement of genomic elements that regulate gene expression such as enhancers. Identifying associations between enhancers and phenotypes is challenging because enhancer activity can be tissue-dependent and functionally conserved despite low sequence conservation. We developed the Tissue-Aware Conservation Inference Toolkit (TACIT) to associate candidate enhancers with species' phenotypes using predictions from machine learning models trained on specific tissues. Applying TACIT to associate motor cortex and parvalbumin-positive interneuron enhancers with neurological phenotypes revealed dozens of enhancer-phenotype associations, including brain size-associated enhancers that interact with genes implicated in microcephaly or macrocephaly. TACIT provides a foundation for identifying enhancers associated with the evolution of any convergently evolved phenotype in any large group of species with aligned genomes.
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Affiliation(s)
- Irene M Kaplow
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Alyssa J Lawler
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Daniel E Schäffer
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Chaitanya Srinivasan
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Heather H Sestili
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Morgan E Wirthlin
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - BaDoi N Phan
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
- Medical Scientist Training Program, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kavya Prasad
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Ashley R Brown
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Xiaomeng Zhang
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Kathleen Foley
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Diane P Genereux
- Broad Institute, Cambridge, MA, USA
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Elinor K Karlsson
- Broad Institute, Cambridge, MA, USA
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Kerstin Lindblad-Toh
- Broad Institute, Cambridge, MA, USA
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Wynn K Meyer
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA
| | - Andreas R Pfenning
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
- Department of Biology, Carnegie Mellon University, Pittsburgh, PA, USA
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Synofzik M, Rugarli E, Reid E, Schüle R. Ataxia and spastic paraplegia in mitochondrial disease. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:79-98. [PMID: 36813322 DOI: 10.1016/b978-0-12-821751-1.00009-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Degenerative ataxias and hereditary spastic paraplegias (HSPs) form a continuous, often overlapping disease spectrum sharing not only phenotypic features and underlying genes, but also cellular pathways and disease mechanisms. Mitochondrial metabolism presents a major molecular theme underlying both multiple ataxias and HSPs, thus indicating a heightened vulnerability of Purkinje cells, spinocerebellar tracts, and motor neurons to mitochondrial dysfunction, which is of particular interest for translational approaches. Mitochondrial dysfunction might be the primary (upstream) or secondary (downstream) result of a genetic defect, with underlying genetic defects in nuclear-encoded genes being much more frequent than in mtDNA genes in both, ataxias and HSPs. Here, we outline the substantial number of ataxias, spastic ataxias and HSPs caused by mutated genes implicated in (primary or secondary) mitochondrial dysfunction, highlighting several key "mitochondrial" ataxias and HSPs which are of particular interest for their frequency, pathogenesis and translational opportunities. We then showcase prototypic mitochondrial mechanisms by which disruption of these ataxia and HSP genes contributes to Purkinje cells or corticospinal neuron dysfunction, thus elucidating hypotheses on Purkinje cells and corticospinal neuron vulnerability to mitochondrial dysfunction.
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Affiliation(s)
- Matthis Synofzik
- Department of Neurodegenerative Diseases, Center for Neurology & Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE), Tübingen, Germany.
| | - Elena Rugarli
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, and Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Evan Reid
- Cambridge Institute for Medical Research and Department of Medical Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Rebecca Schüle
- Department of Neurodegenerative Diseases, Center for Neurology & Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany; German Center of Neurodegenerative Diseases (DZNE), Tübingen, Germany
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9
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Fink JK. The hereditary spastic paraplegias. HANDBOOK OF CLINICAL NEUROLOGY 2023; 196:59-88. [PMID: 37620092 DOI: 10.1016/b978-0-323-98817-9.00022-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
The hereditary spastic paraplegias (HSPs) are a group of more than 90 genetic disorders in which lower extremity spasticity and weakness are either the primary neurologic impairments ("uncomplicated HSP") or when accompanied by other neurologic deficits ("complicated HSP"), important features of the clinical syndrome. Various genetic types of HSP are inherited such as autosomal dominant, autosomal recessive, X-linked, and maternal (mitochondrial) traits. Symptoms that begin in early childhood may be nonprogressive and resemble spastic diplegic cerebral palsy. Symptoms that begin later, typically progress insidiously over a number of years. Genetic testing is able to confirm the diagnosis for many subjects. Insights from gene discovery indicate that abnormalities in diverse molecular processes underlie various forms of HSP, including disturbance in axon transport, endoplasmic reticulum morphogenesis, vesicle transport, lipid metabolism, and mitochondrial function. Pathologic studies in "uncomplicated" HSP have shown axon degeneration particularly involving the distal ends of corticospinal tracts and dorsal column fibers. Treatment is limited to symptom reduction including amelioration of spasticity, reducing urinary urgency, proactive physical therapy including strengthening, stretching, balance, and agility exercise.
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Affiliation(s)
- John K Fink
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.
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10
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Panzeri E, Citterio A, Martinuzzi A, Ancona V, Martini E, Bassi MT. Case report: A novel FARS2 deletion and a missense variant in a child with complicated, rapidly progressive spastic paraplegia. Front Genet 2023; 14:1130687. [PMID: 37152989 PMCID: PMC10154595 DOI: 10.3389/fgene.2023.1130687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/23/2023] [Indexed: 05/09/2023] Open
Abstract
Defects in FARS2 are associated with either epileptic phenotypes or a spastic paraplegia subtype known as SPG77. Here, we describe an 8-year-old patient with severe and complicated spastic paraplegia, carrying a missense variant (p.Pro361Leu) and a novel intragenic deletion in FARS2. Of note, the disease is unexpectedly progressing rapidly and in a biphasic way differently from the previously reported cases. Our study provides the first detailed molecular characterization of a FARS2 deletion and its underlying molecular mechanism, and demonstrates the need for combining different tools to improve the diagnostic rate.
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Affiliation(s)
- Elena Panzeri
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Italy
- *Correspondence: Elena Panzeri,
| | - Andrea Citterio
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Italy
| | - Andrea Martinuzzi
- Department of Neurorehabilitation, Scientific Institute IRCCS E. Medea, Conegliano, Italy
| | - Vera Ancona
- Department of Neurorehabilitation, Scientific Institute IRCCS E. Medea, Conegliano, Italy
| | - Eleonora Martini
- Department of Neurorehabilitation, Scientific Institute IRCCS E. Medea, Conegliano, Italy
| | - Maria Teresa Bassi
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Italy
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11
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Li L, Ma J, Wang J, Dong L, Liu S. Two Chinese siblings of combined oxidative phosphorylation deficiency 14 caused by compound heterozygous variants in FARS2. Eur J Med Res 2022; 27:184. [PMID: 36155627 PMCID: PMC9511728 DOI: 10.1186/s40001-022-00808-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/01/2022] [Indexed: 11/10/2022] Open
Abstract
Background As a rare mitochondrial disease, combined oxidative phosphorylation deficiency 14 (COXPD14) is caused by biallelic variants in the phenylalanyl-tRNA synthetase 2, mitochondrial gene (FARS2) with clinical features of developmental delay, an elevated lactate level, early-onset encephalopathy, liver failure, and hypotonia. The objectives of this study were to analyze the clinical and molecular features of two Chinese siblings affected with COXPD14, and to review relevant literature. Methods Mutation screening was performed by whole exome sequencing (WES) in combination with Sanger sequencing validation to identify the disease-causing variants of the two patients. Results The two siblings presented with severe clinical features and both progressed aggressively and failed to survive after treatment abandonment. We identified two compound heterozygous FARS2 variants c.925G>A p.Gly309Ser and c.943G>C p.Gly315Arg in this proband, which were inherited from the unaffected father and mother, respectively. In addition, Sanger sequencing confirmed that the elder affected sister carried the same compound heterozygous variants. The c.925G>A p.Gly309Ser variant is known and commonly reported in COXPD14 patients, while c.943G>C p.Gly315Arg is a novel one. Neither of the variants was found in 100 Chinese healthy controls. Both variants were classified as “deleterious” and were located in the highly conserved regions of the protein. The above results suggested that the two variants were likely causative in this COXPD14-affected pedigree. Conclusions Our study expands the mutation spectrum of FARS2 and highlights the importance of genetic testing in the diagnosis of diseases with a wide variety of phenotypes, especially in the differential diagnosis of diseases.
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Affiliation(s)
- Liangshan Li
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Jianhua Ma
- Department of Reproductive Medicine, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jingli Wang
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Liping Dong
- Neonatal Disease Screening Center, Zibo Maternal and Child Health Hospital, Zibo, 255000, China.
| | - Shiguo Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China.
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12
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Abstract
The human brain consumes five orders of magnitude more energy than the sun by unit of mass and time. This staggering bioenergetic cost serves mostly synaptic transmission and actin cytoskeleton dynamics. The peak of both brain bioenergetic demands and the age of onset for neurodevelopmental disorders is approximately 5 years of age. This correlation suggests that defects in the machinery that provides cellular energy would be causative and/or consequence of neurodevelopmental disorders. We explore this hypothesis from the perspective of the machinery required for the synthesis of the electron transport chain, an ATP-producing and NADH-consuming enzymatic cascade. The electron transport chain is constituted by nuclear- and mitochondrial-genome-encoded subunits. These subunits are synthesized by the 80S and the 55S ribosomes, which are segregated to the cytoplasm and the mitochondrial matrix, correspondingly. Mitochondrial protein synthesis by the 55S ribosome is the rate-limiting step in the synthesis of electron transport chain components, suggesting that mitochondrial protein synthesis is a bottleneck for tissues with high bionergetic demands. We discuss genetic defects in the human nuclear and mitochondrial genomes that affect these protein synthesis machineries and cause a phenotypic spectrum spanning autism spectrum disorders to neurodegeneration during neurodevelopment. We propose that dysregulated mitochondrial protein synthesis is a chief, yet understudied, causative mechanism of neurodevelopmental and behavioral disorders.
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13
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Chen X, Liu F, Li B, Wang Y, Yuan L, Yin A, Chen Q, Hu W, Yao Y, Zhang M, Wu Y, Chen K. Neuropathy-associated Fars2 deficiency affects neuronal development and potentiates neuronal apoptosis by impairing mitochondrial function. Cell Biosci 2022; 12:103. [PMID: 35794642 PMCID: PMC9258231 DOI: 10.1186/s13578-022-00838-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 06/23/2022] [Indexed: 11/22/2022] Open
Abstract
Background Neurodegenerative diseases encompass an extensive and heterogeneous group of nervous system disorders which are characterized by progressive degeneration and death of neurons. Many lines of evidence suggest the participation of mitochondria dysfunction in these diseases. Mitochondrial phenylalanyl-tRNA synthetase, encoded by FARS2, catalyzes the transfer of phenylalanine to its cognate tRNA for protein synthesis. As a member of mt-aaRSs genes, FARS2 missense homozygous mutation c.424G > T (p.D142Y) found in a Chinese consanguineous family first built the relationship between pure hereditary spastic paraplegia (HSP) and FARS2 gene. More FARS2 variations were subsequently found to cause heterogeneous group of neurologic disorders presenting three main phenotypic manifestations: infantile-onset epileptic mitochondrial encephalopathy, later-onset spastic paraplegia and juvenile onset refractory epilepsy. Studies showed that aminoacylation activity is frequently disrupt in cases with FARS2 mutations, indicating a loss-of-function mechanism. However, the underlying pathogenesis of neuropathy-associated Fars2 deficiency is still largely unknown. Results Early gestation lethality of global Fars2 knockout mice was observed prior to neurogenesis. The conditional Fars2 knockout-mouse model delayed lethality to late-gestation, resulting in a thinner cortex and an enlarged ventricle which is consist with the MRI results revealing cortical atrophy and reduced cerebral white matter volume in FARS2-deficient patients. Delayed development of neurite outgrowth followed by neuronal apoptosis was confirmed in Fars2-knockdown mouse primary cultured neurons. Zebrafish, in which fars2 was knocked down, exhibited aberrant motor neuron function including reduced locomotor capacity which well restored the spastic paraplegia phenotype of FARS2-deficient patients. Altered mitochondrial protein synthesis and reduced levels of oxidative phosphorylation complexes were detected in Fars2-deficient samples. And thus, reduced ATP, total NAD levels and mitochondrial membrane potential, together with increased ROS production, revealed mitochondrial dysfunction both in vitro and in vivo. Dctn3 is a potential downstream molecule in responds to Fars2 deficient in neurons, which may provide some evidence for the development of pathogenesis study and therapeutic schedule. Conclusions The Fars2 deficiency genetic models developed in this study cover the typical clinical manifestations in FARS2 patients, and help clarify how neuropathy-associated Fars2 deficiency, by damaging the mitochondrial respiratory chain and impairing mitochondrial function, affects neuronal development and potentiates neuronal cell apoptosis. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-022-00838-y.
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Affiliation(s)
- Xihui Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Fangfang Liu
- Department of Neurobiology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Bowen Li
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Yufeng Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - Lijuan Yuan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Department of General Surgery, Tangdu Hospital, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Anan Yin
- Department of Neurosurgery, Xijing Institute of Clinical Neuroscience, Department of Plastic surgery, Xijing Hospital, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Qi Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China
| | - Weihong Hu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - Yan Yao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - Mengjie Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.,Medical Genetics, Yan'an University, Yan'an, Shaanxi, People's Republic of China
| | - YuanMing Wu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China. .,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.
| | - Kun Chen
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, School of Basic Medicine, Air Force Medical University, Xi'an, Shaanxi, People's Republic of China.
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14
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Hereditary Spastic Paraplegia: An Update. Int J Mol Sci 2022; 23:ijms23031697. [PMID: 35163618 PMCID: PMC8835766 DOI: 10.3390/ijms23031697] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/21/2021] [Accepted: 01/28/2022] [Indexed: 12/12/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) is a rare neurodegenerative disorder with the predominant clinical manifestation of spasticity in the lower extremities. HSP is categorised based on inheritance, the phenotypic characters, and the mode of molecular pathophysiology, with frequent degeneration in the axon of cervical and thoracic spinal cord’s lateral region, comprising the corticospinal routes. The prevalence ranges from 0.1 to 9.6 subjects per 100,000 reported around the globe. Though modern medical interventions help recognize and manage the disorder, the symptomatic measures remain below satisfaction. The present review assimilates the available data on HSP and lists down the chromosomes involved in its pathophysiology and the mutations observed in the respective genes on the chromosomes. It also sheds light on the treatment available along with the oral/intrathecal medications, physical therapies, and surgical interventions. Finally, we have discussed the related diagnostic techniques as well as the linked pharmacogenomics studies under future perspectives.
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15
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Clinical Heterogeneity in MT-ATP6 Pathogenic Variants: Same Genotype-Different Onset. Cells 2022; 11:cells11030489. [PMID: 35159298 PMCID: PMC8834419 DOI: 10.3390/cells11030489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/22/2022] [Accepted: 01/26/2022] [Indexed: 12/12/2022] Open
Abstract
Human mitochondrial disease exhibits large variation of clinical phenotypes, even in patients with the same causative gene defect. We illustrate this heterogeneity by confronting clinical and biochemical data of two patients with the uncommon pathogenic homoplasmic NC_012920.1(MT-ATP6):m.9035T>C variant in MT-ATP6. Patient 1 presented as a toddler with severe motor and speech delay and spastic ataxia without extra-neurologic involvement. Patient 2 presented in adolescence with ataxia and ophthalmoplegia without cognitive or motor impairment. Respiratory chain complex activities were normal in cultured skin fibroblasts from both patients when calculated as ratios over citrate synthase activity. Native gels found presence of subcomplexes of complex V in fibroblast and/or skeletal muscle. Bioenergetic measurements in fibroblasts from both patients detected reduced spare respiratory capacities and altered extracellular acidification rates, revealing a switch from mitochondrial respiration to glycolysis to uphold ATP production. Thus, in contrast to the differing disease presentation, biochemical evidence of mitochondrial deficiency turned out quite similar. We conclude that biochemical analysis remains a valuable tool to confirm the genetic diagnosis of mitochondrial disease, especially in patients with new gene variants or atypical clinical presentation.
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16
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Fan W, Jin X, Xu M, Xi Y, Lu W, Yang X, Guan MX, Ge W. FARS2 deficiency in Drosophila reveals the developmental delay and seizure manifested by aberrant mitochondrial tRNA metabolism. Nucleic Acids Res 2021; 49:13108-13121. [PMID: 34878141 PMCID: PMC8682739 DOI: 10.1093/nar/gkab1187] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 11/08/2021] [Accepted: 11/17/2021] [Indexed: 01/16/2023] Open
Abstract
Mutations in genes encoding mitochondrial aminoacyl-tRNA synthetases are linked to diverse diseases. However, the precise mechanisms by which these mutations affect mitochondrial function and disease development are not fully understood. Here, we develop a Drosophila model to study the function of dFARS2, the Drosophila homologue of the mitochondrial phenylalanyl–tRNA synthetase, and further characterize human disease-associated FARS2 variants. Inactivation of dFARS2 in Drosophila leads to developmental delay and seizure. Biochemical studies reveal that dFARS2 is required for mitochondrial tRNA aminoacylation, mitochondrial protein stability, and assembly and enzyme activities of OXPHOS complexes. Interestingly, by modeling FARS2 mutations associated with human disease in Drosophila, we provide evidence that expression of two human FARS2 variants, p.G309S and p.D142Y, induces seizure behaviors and locomotion defects, respectively. Together, our results not only show the relationship between dysfunction of mitochondrial aminoacylation system and pathologies, but also illustrate the application of Drosophila model for functional analysis of human disease-causing variants.
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Affiliation(s)
- Wenlu Fan
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China
| | - Xiaoye Jin
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China
| | - Man Xu
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China
| | - Yongmei Xi
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China
| | - Weiguo Lu
- Department of Gynecologic Oncology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China.,Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiaohang Yang
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Genetic and Developmental Disorders, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Min-Xin Guan
- Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Genetic and Developmental Disorders, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Wanzhong Ge
- Division of Human Reproduction and Developmental Genetics, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.,Institute of Genetics, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, China.,Zhejiang Provincial Key Laboratory of Precision Diagnosis and Therapy for Major Gynecological Diseases, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, China.,Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China
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17
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Li B, Chen K, Liu F, Zhang J, Chen X, Chen T, Chen Q, Yao Y, Hu W, Wang L, Wu Y. Developmental Angiogenesis Requires the Mitochondrial Phenylalanyl-tRNA Synthetase. Front Cardiovasc Med 2021; 8:724846. [PMID: 34540921 PMCID: PMC8440837 DOI: 10.3389/fcvm.2021.724846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/04/2021] [Indexed: 12/03/2022] Open
Abstract
Background: Mitochondrial aminoacyl-tRNA synthetases (mtARSs) catalyze the binding of specific amino acids to their cognate tRNAs and play an essential role in the synthesis of proteins encoded by mitochondrial DNA. Defects in mtARSs have been linked to human diseases, but their tissue-specific pathophysiology remains elusive. Here we examined the role of mitochondrial phenylalanyl-tRNA synthetase (FARS2) in developmental angiogenesis and its potential contribution to the pathogenesis of cardiovascular disease. Methods: Morpholinos were injected into fertilized zebrafish ova to establish an in vivo fars2 knock-down model. A visualization of the vasculature was achieved by using Tg (fli1: EGFP)y1 transgenic zebrafish. In addition, small interference RNAs (siRNAs) were transferred into human umbilical vein endothelial cells (HUVECs) to establish an in vitro FARS2 knock-down model. Cell motility, proliferation, and tubulogenesis were determined using scratch-wound CCK8, transwell-based migration, and tube formation assays. In addition, mitochondria- and non-mitochondria-related respiration were evaluated using a Seahorse XF24 analyzer and flow cytometry assays. Analyses of the expression levels of transcripts and proteins were performed using qRT-PCR and western blotting, respectively. Results: The knock-down of fars2 hampered the embryonic development in zebrafish and delayed the formation of the vasculature in Tg (fli1: EGFP)y1 transgenic zebrafish. In addition, the siRNA-mediated knock-down of FARS2 impaired angiogenesis in HUVECs as indicated by decreased cell motility and tube formation capacity. The knock-down of FARS2 also produced variable decreases in mitochondrial- and non-mitochondrial respiration in HUVECs and disrupted the regulatory pathways of angiogenesis in both HUVECs and zebrafish. Conclusion: Our current work offers novel insights into angiogenesis defects and cardiovascular diseases induced by FARS2 deficiency.
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Affiliation(s)
- Bowen Li
- Department of Biochemistry and Molecular Biology, Air Force Medical University, Xi'an, China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, China
| | - Kun Chen
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Centre, Air Force Medical University, Xi'an, China
| | - Fangfang Liu
- Department of Neurosciences, Air Force Medical University, Xi'an, China
| | - Juan Zhang
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Northwest University, Xi'an, China
| | - Xihui Chen
- Department of Biochemistry and Molecular Biology, Air Force Medical University, Xi'an, China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, China
| | - Tangdong Chen
- Department of Biochemistry and Molecular Biology, Air Force Medical University, Xi'an, China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, China
| | - Qi Chen
- Department of Biochemistry and Molecular Biology, Air Force Medical University, Xi'an, China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, China
| | - Yan Yao
- Department of Clinical Medicine, Yan'an University, Yan'an, China
| | - Weihong Hu
- Department of Clinical Medicine, Yan'an University, Yan'an, China
| | - Li Wang
- Department of Biochemistry and Molecular Biology, Air Force Medical University, Xi'an, China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, China.,School of Aerospace Medicine, Air Force Medical University, Xi'an, China
| | - Yuanming Wu
- Department of Biochemistry and Molecular Biology, Air Force Medical University, Xi'an, China.,Shaanxi Provincial Key Laboratory of Clinic Genetics, Air Force Medical University, Xi'an, China
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18
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Ducoli L, Agrawal S, Hon CC, Ramilowski JA, Sibler E, Tagami M, Itoh M, Kondo N, Abugessaisa I, Hasegawa A, Kasukawa T, Suzuki H, Carninci P, Shin JW, de Hoon MJL, Detmar M. The choice of negative control antisense oligonucleotides dramatically impacts downstream analysis depending on the cellular background. BMC Genom Data 2021; 22:33. [PMID: 34521352 PMCID: PMC8439024 DOI: 10.1186/s12863-021-00992-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/29/2021] [Indexed: 11/18/2022] Open
Abstract
Background The lymphatic and the blood vasculature are closely related systems that collaborate to ensure the organism’s physiological function. Despite their common developmental origin, they present distinct functional fates in adulthood that rely on robust lineage-specific regulatory programs. The recent technological boost in sequencing approaches unveiled long noncoding RNAs (lncRNAs) as prominent regulatory players of various gene expression levels in a cell-type-specific manner. Results To investigate the potential roles of lncRNAs in vascular biology, we performed antisense oligonucleotide (ASO) knockdowns of lncRNA candidates specifically expressed either in human lymphatic or blood vascular endothelial cells (LECs or BECs) followed by Cap Analysis of Gene Expression (CAGE-Seq). Here, we describe the quality control steps adopted in our analysis pipeline before determining the knockdown effects of three ASOs per lncRNA target on the LEC or BEC transcriptomes. In this regard, we especially observed that the choice of negative control ASOs can dramatically impact the conclusions drawn from the analysis depending on the cellular background. Conclusion In conclusion, the comparison of negative control ASO effects on the targeted cell type transcriptomes highlights the essential need to select a proper control set of multiple negative control ASO based on the investigated cell types. Supplementary Information The online version contains supplementary material available at 10.1186/s12863-021-00992-1.
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Affiliation(s)
- Luca Ducoli
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Vladimir-Prelog-Weg 3, 8093, Zurich, Switzerland.,Molecular Life Sciences PhD Program, Swiss Federal Institute of Technology and University of Zurich, Zurich, Switzerland
| | - Saumya Agrawal
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Chung-Chau Hon
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Jordan A Ramilowski
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Eliane Sibler
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Vladimir-Prelog-Weg 3, 8093, Zurich, Switzerland.,Molecular Life Sciences PhD Program, Swiss Federal Institute of Technology and University of Zurich, Zurich, Switzerland
| | - Michihira Tagami
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Masayoshi Itoh
- RIKEN Preventive Medicine and Diagnosis Innovation Program, RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Naoto Kondo
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Imad Abugessaisa
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Akira Hasegawa
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Takeya Kasukawa
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Harukazu Suzuki
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Piero Carninci
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan.,Human Technopole, Via Cristina Belgioioso 171, 20157, Milan, Italy
| | - Jay W Shin
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Michiel J L de Hoon
- RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa, 230-0045, Japan.,RIKEN Center for Life Science Technologies, Yokohama, Kanagawa, 230-0045, Japan
| | - Michael Detmar
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Vladimir-Prelog-Weg 3, 8093, Zurich, Switzerland.
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19
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Darios F, Coarelli G, Durr A. Genetics in hereditary spastic paraplegias: Essential but not enough. Curr Opin Neurobiol 2021; 72:8-14. [PMID: 34403957 DOI: 10.1016/j.conb.2021.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/04/2021] [Accepted: 07/14/2021] [Indexed: 12/01/2022]
Abstract
Hereditary spastic paraplegias consist of a group of rare neurodegenerative diseases characterized by lower limb spasticity. These inherited Mendelian disorders show high genetic variability associated with wide clinical diversity. Pathophysiological investigations have suggested that mutations in genes affecting the same cellular pathway generally lead to similar clinical symptoms, highlighting the importance of genetic mutation in these diseases. However, phenotype-genotype correlations have failed to explain the observed large inter-individual variability linked to mutations in a single gene, suggesting that genetics alone is not sufficient to explain symptom diversity. The identification of biomarkers, such as neurofilament light chain, could fill the gap and predict disease evolution.
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Affiliation(s)
- Frédéric Darios
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France.
| | - Giulia Coarelli
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France; AP-HP, Hôpital de la Pitié Salpêtrière, Paris, 75013, France
| | - Alexandra Durr
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France; AP-HP, Hôpital de la Pitié Salpêtrière, Paris, 75013, France.
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20
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Roux CJ, Barcia G, Schiff M, Sissler M, Levy R, Dangouloff-Ros V, Desguerre I, Edvardson S, Elpeleg O, Rötig A, Munnich A, Boddaert N. Phenotypic diversity of brain MRI patterns in mitochondrial aminoacyl-tRNA synthetase mutations. Mol Genet Metab 2021; 133:222-229. [PMID: 33972171 DOI: 10.1016/j.ymgme.2021.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/15/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND PURPOSE Mitochondrial aminoacyl-tRNA synthetases-encoded by ARS2 genes-are evolutionarily conserved enzymes that catalyse the attachment of amino acids to their cognate tRNAs, ensuring the accuracy of the mitochondrial translation process. ARS2 gene mutations are associated with a wide range of clinical presentations affecting the CNS. METHODS Two senior neuroradiologists analysed brain MRI of 25 patients (age range: 3 d-25 yrs.; 11 males; 14 females) with biallelic pathogenic variants of 11 ARS2 genes in a retrospective study conducted between 2002 and 2019. RESULTS Though several combinations of brain MRI anomalies were highly suggestive of specific aetiologies (DARS2, EARS2, AARS2 and RARS2 mutations), our study detected no MRI pattern common to all patients. Stroke-like lesions were associated with pathogenic SARS2 and FARS2 variants. We also report early onset cerebellar atrophy and calcifications in AARS2 mutations, early white matter involvement in RARS2 mutations, and absent involvement of thalami in EARS2 mutations. Finally, our findings show that normal brain MRI results do not exclude the presence of ARS2 mutations: 5 patients with normal MRI images were carriers of pathogenic IARS2, YARS2, and FARS2 variants. CONCLUSION Our study extends the spectrum of brain MRI anomalies associated with pathogenic ARS2 variants and suggests ARS2 mutations are largely underdiagnosed.
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Affiliation(s)
- Charles-Joris Roux
- Department of Paediatric Radiology, Hôpital Necker-Enfants Malades, Paris, France.
| | - Giulia Barcia
- Department of Genetics, Hospital Necker-Enfants Malades, Paris, France
| | - Manuel Schiff
- Institut Imagine, INSERM UMR 1163, Paris, France; Necker Hospital, APHP, Reference Center for Inborn Error of Metabolism, Pediatrics Department, University of Paris, Paris, France
| | - Marie Sissler
- Institut Européen de Chimie et Biologie, INSERM U1212, CNRS UMR 5320, University of Bordeaux, Pessac, France
| | - Raphaël Levy
- Department of Paediatric Radiology, Hôpital Necker-Enfants Malades, Paris, France
| | | | - Isabelle Desguerre
- Department of Neurology and Metabolism, Hôpital Necker-Enfants Malades, Paris, France
| | - Shimon Edvardson
- Department of Genetics, Hadassah University Hospital, Jerusalem, Israel
| | - Orli Elpeleg
- Department of Genetics, Hadassah University Hospital, Jerusalem, Israel
| | - Agnès Rötig
- Institut Imagine, INSERM UMR 1163, Paris, France
| | - Arnold Munnich
- Department of Genetics, Hospital Necker-Enfants Malades, Paris, France; Institut Imagine, INSERM UMR 1163, Paris, France
| | - Nathalie Boddaert
- Department of Paediatric Radiology, Hôpital Necker-Enfants Malades, Paris, France; Institut Imagine, INSERM UMR 1163, Paris, France
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21
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Powers KT, Santoro JD. Metabolic stroke-like episode in a child with FARS2 mutation and SARS-CoV-2 positive cerebrospinal fluid. Mol Genet Metab Rep 2021; 27:100756. [PMID: 33875935 PMCID: PMC8045429 DOI: 10.1016/j.ymgmr.2021.100756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 04/05/2021] [Indexed: 11/24/2022] Open
Abstract
The novel SARS-CoV-2 has infected over 48 million persons around the world. Children have been spared with regards to symptoms and sequelae of this highly infectious virus and in those with neurologic issues, the virus has not been present in the cerebrospinal fluid. Here, the authors present the first case of metabolic stroke-like episode with SARS-CoV-2 present in the cerebrospinal fluid in a child with a FARS2 deficiency. This report suggests a possible association of SARS-COV-2 infection and metabolic stroke-like episode, even in the absence of a phenotype classically associated with metabolic stroke-like episodes.
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Affiliation(s)
- Kelly T Powers
- Division of Neurology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Jonathan D Santoro
- Division of Neurology, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Department of Neurology, Keck School of Medicine at USC, USA
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22
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Novel FARS2 variants in patients with early onset encephalopathy with or without epilepsy associated with long survival. Eur J Hum Genet 2020; 29:533-538. [PMID: 33168986 DOI: 10.1038/s41431-020-00757-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 09/10/2020] [Accepted: 10/20/2020] [Indexed: 11/08/2022] Open
Abstract
Mitochondrial translation is essential for the biogenesis of the mitochondrial oxidative phosphorylation system (OXPHOS) that synthesizes the bulk of ATP for the cell. Hypomorphic and loss-of-function variants in either mitochondrial DNA or in nuclear genes that encode mitochondrial translation factors can result in impaired OXPHOS biogenesis and mitochondrial diseases with variable clinical presentations. Compound heterozygous or homozygous missense and frameshift variants in the FARS2 gene, that encodes the mitochondrial phenylalanyl-tRNA synthetase, are commonly linked to either early-onset epileptic mitochondrial encephalopathy or spastic paraplegia. Here, we expand the genetic spectrum of FARS2-linked disease with three patients carrying novel compound heterozygous variants in the FARS2 gene and presenting with spastic tetraparesis, axial hypotonia and myoclonic epilepsy in two cases.
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Hotait M, Nasreddine W, El-Khoury R, Dirani M, Nawfal O, Beydoun A. FARS2 Mutations: More Than Two Phenotypes? A Case Report. Front Genet 2020; 11:787. [PMID: 32774346 PMCID: PMC7387725 DOI: 10.3389/fgene.2020.00787] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/02/2020] [Indexed: 12/04/2022] Open
Abstract
FARS2, a nuclear gene, encodes the mitochondrial phenylalanyl-tRNA synthetase (mtPheRS). Previous reports have described two distinct phenotypes linked to FARS2 gene mutation: an early onset epileptic encephalopathy and spastic paraplegia. This report describes a distinctive phenotype of FARS2-linked, juvenile onset refractory epilepsy, caused by a hemizygous mutation in a compound heterozygous state (p.V197M and exon 2 microdeletion). A 17-year- old woman with normal development presented with a super refractory focal motor status epilepticus. Only an emergency life-saving surgery aborted her status after all therapeutic interventions, including anesthesia, failed to control her seizures. Pathological and biochemical activities on muscle biopsy showed mitochondrial proliferation with enhanced isolated activities of complexes II and IV, suggestive of a compensatory mechanism for the bioenergetic deficiency. Postoperatively, the patient started experiencing focal aware motor seizures originating from the contralateral hemisphere after being seizure free for a few months. This report suggests a third phenotypic manifestation of FARS2 gene mutation.
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Affiliation(s)
- Mostafa Hotait
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Wassim Nasreddine
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Riyad El-Khoury
- Department of Pathology and Laboratory Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Maya Dirani
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Omar Nawfal
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Ahmad Beydoun
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
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24
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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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25
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Meszarosova AU, Seeman P, Jencik J, Drabova J, Cibochova R, Stellmachova J, Safka Brozkova D. Two types of recessive hereditary spastic paraplegia in Roma patients in compound heterozygous state; no ethnically prevalent variant found. Neurosci Lett 2020; 721:134800. [PMID: 32007496 DOI: 10.1016/j.neulet.2020.134800] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 01/09/2020] [Accepted: 01/29/2020] [Indexed: 10/25/2022]
Abstract
Hereditary spastic paraplegia (HSP or SPG) is a group of rare upper motor neuron diseases. As some ethnically-specific, disease-causing homozygous variants were described in the Czech Roma population, we hypotesised that some prevalent HSP-causing variant could exist in this population. Eight Czech Roma patients were found in a large group of Czech patients with suspected HSP and were tested using gene panel massively parallel sequencing (MPS). Two of the eight were diagnosed with SPG11 and SPG77, respectively. The SPG77 patient manifests a pure HSP phenotype, which is unusual for this SPG type. Both patients are compound heterozygotes for two different variants in the SPG11 (c.1603-1G>A and del ex. 16-18) and FARS2 (c.1082C>T and del ex.1-2) genes respectively; the three variants are novel. In order to find a potential ethnically-specific, disease-causing variant for HSP, we tested the heterozygote frequency of these variants among 130 anonymised DNA samples of Czech Roma individuals without clinical signs of HSP (HPS-negative). A novel deletion of ex.16-18 in the SPG11 gene was found in a heterozygous state in one individual in the HSP-negative group. Haplotype analysis showed that this individual and the patient with SPG11 shared the same haplotype. This supports the assumption that the identified SPG11 deletion could be a founder mutation in the Czech Roma population. In some Roma patients the disease may also be caused by two different biallelic pathogenic mutations.
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Affiliation(s)
- Anna Uhrova Meszarosova
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic.
| | - Pavel Seeman
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Jan Jencik
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Jana Drabova
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Renata Cibochova
- Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
| | - Julia Stellmachova
- Department of Medical Genetics, Palacky University Hospital, Olomouc, Czech Republic
| | - Dana Safka Brozkova
- DNA Laboratory, Department of Paediatric Neurology, 2nd Faculty of Medicine Charles University and University Hospital Motol, Prague, Czech Republic
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26
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Morales-Briceño H, Mohammad SS, Post B, Fois AF, Dale RC, Tchan M, Fung VSC. Clinical and neuroimaging phenotypes of genetic parkinsonism from infancy to adolescence. Brain 2019; 143:751-770. [DOI: 10.1093/brain/awz345] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/29/2019] [Accepted: 09/06/2019] [Indexed: 12/11/2022] Open
Abstract
AbstractGenetic early-onset parkinsonism presenting from infancy to adolescence (≤21 years old) is a clinically diverse syndrome often combined with other hyperkinetic movement disorders, neurological and imaging abnormalities. The syndrome is genetically heterogeneous, with many causative genes already known. With the increased use of next-generation sequencing in clinical practice, there have been novel and unexpected insights into phenotype-genotype correlations and the discovery of new disease-causing genes. It is now recognized that mutations in a single gene can give rise to a broad phenotypic spectrum and that, conversely different genetic disorders can manifest with a similar phenotype. Accurate phenotypic characterization remains an essential step in interpreting genetic findings in undiagnosed patients. However, in the past decade, there has been a marked expansion in knowledge about the number of both disease-causing genes and phenotypic spectrum of early-onset cases. Detailed knowledge of genetic disorders and their clinical expression is required for rational planning of genetic and molecular testing, as well as correct interpretation of next-generation sequencing results. In this review we examine the relevant literature of genetic parkinsonism with ≤21 years onset, extracting data on associated movement disorders as well as other neurological and imaging features, to delineate syndromic patterns associated with early-onset parkinsonism. Excluding PRKN (parkin) mutations, >90% of the presenting phenotypes have a complex or atypical presentation, with dystonia, abnormal cognition, pyramidal signs, neuropsychiatric disorders, abnormal imaging and abnormal eye movements being the most common features. Furthermore, several imaging features and extraneurological manifestations are relatively specific for certain disorders and are important diagnostic clues. From the currently available literature, the most commonly implicated causes of early-onset parkinsonism have been elucidated but diagnosis is still challenging in many cases. Mutations in ∼70 different genes have been associated with early-onset parkinsonism or may feature parkinsonism as part of their phenotypic spectrum. Most of the cases are caused by recessively inherited mutations, followed by dominant and X-linked mutations, and rarely by mitochondrially inherited mutations. In infantile-onset parkinsonism, the phenotype of hypokinetic-rigid syndrome is most commonly caused by disorders of monoamine synthesis. In childhood and juvenile-onset cases, common genotypes include PRKN, HTT, ATP13A2, ATP1A3, FBX07, PINK1 and PLA2G6 mutations. Moreover, Wilson’s disease and mutations in the manganese transporter are potentially treatable conditions and should always be considered in the differential diagnosis in any patient with early-onset parkinsonism.
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Affiliation(s)
- Hugo Morales-Briceño
- Movement Disorders Unit, Neurology Department, Westmead Hospital, Westmead, NSW 2145, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW 2145, Australia
| | - Shekeeb S Mohammad
- Neurology Department, Children’s Westmead Hospital, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Bart Post
- Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Parkinson Centre Nijmegen (ParC) Nijmegen, The Netherlands
| | - Alessandro F Fois
- Movement Disorders Unit, Neurology Department, Westmead Hospital, Westmead, NSW 2145, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW 2145, Australia
| | - Russell C Dale
- Neurology Department, Children’s Westmead Hospital, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Michel Tchan
- Sydney Medical School, University of Sydney, Sydney, NSW 2145, Australia
- Department of Genetic Medicine, Westmead Hospital, Westmead, NSW 2145, Australia
| | - Victor S C Fung
- Movement Disorders Unit, Neurology Department, Westmead Hospital, Westmead, NSW 2145, Australia
- Sydney Medical School, University of Sydney, Sydney, NSW 2145, Australia
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Genes and Variants Underlying Human Congenital Lactic Acidosis-From Genetics to Personalized Treatment. J Clin Med 2019; 8:jcm8111811. [PMID: 31683770 PMCID: PMC6912785 DOI: 10.3390/jcm8111811] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 02/07/2023] Open
Abstract
Congenital lactic acidosis (CLA) is a rare condition in most instances due to a range of inborn errors of metabolism that result in defective mitochondrial function. Even though the implementation of next generation sequencing has been rapid, the diagnosis rate for this highly heterogeneous allelic condition remains low. The present work reports our group’s experience of using a clinical/biochemical analysis system in conjunction with genetic findings that facilitates the taking of timely clinical decisions with minimum need for invasive procedures. The system’s workflow combines different metabolomics datasets and phenotypic information with the results of clinical exome sequencing and/or RNA analysis. The system’s use detected genetic variants in 64% of a cohort of 39 CLA-patients; these variants, 14 of which were novel, were found in 19 different nuclear and two mitochondrial genes. For patients with variants of unknown significance, the genetic analysis was combined with functional genetic and/or bioenergetics analyses in an attempt to detect pathogenicity. Our results warranted subsequent testing of antisense therapy to rescue the abnormal splicing in cultures of fibroblasts from a patient with a defective GFM1 gene. The discussed system facilitates the diagnosis of CLA by avoiding the need to use invasive techniques and increase our knowledge of the causes of this condition.
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Chen Z, Zhang Y. A patient with juvenile-onset refractory status epilepticus caused by two novel compound heterozygous mutations in FARS2 gene. Int J Neurosci 2019; 129:1094-1097. [PMID: 31329004 DOI: 10.1080/00207454.2019.1634071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
FARS2 encodes mitochondrial phenylalanyl transfer ribonucleic acid (RNA) synthetase and is implicated in autosomal recessive combined oxidative phosphorylation deficiency 14. The clinical manifestation can be divided into early onset epileptic phenotype and spastic paraplegia phenotype. The purpose of this study was to report a case of juvenile manifesting refractory epilepsy caused by two novel compound heterozygous mutations in the FARS2 gene. Microscopic and histochemical examination as well as next-generation sequencing and reconstruction of the three-dimensional structure of FARS2 protein were performed. A 17-year-old man with no developmental delays suffered from generalized tonic-clonic convulsion since 12 years of age and developed refractory status epilepticus 5 years later. No specific etiology was found following brain imaging, muscle biopsy and metabolic studies. DNA sequencing identified two novel compound heterozygous mutations in FARS2, (p.V197M and p.F402S), derived from each parents, respectively. These mutations affected the structure or thermodynamic stability of the protein. This is a case report of juvenile-onset refractory epilepsy caused by two novel compound heterozygous mutations in the FARS2 gene. This case confirms and expands the clinicalphenotype and the genotypic spectrum of the FARS2 gene.
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Affiliation(s)
- Zhongyun Chen
- Department of Neurology, Xuanwu Hospital, Capital Medical University , Beijing , China
| | - Yan Zhang
- Department of Neurology, Xuanwu Hospital, Capital Medical University , Beijing , China
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29
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Chakraborty S, Ibba M, Banerjee R. Biophysical characterization Of Alpers encephalopathy associated mutants of human mitochondrial phenylalanyl-tRNA synthetase. IUBMB Life 2019; 71:1141-1149. [PMID: 31241862 DOI: 10.1002/iub.2114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 06/06/2019] [Indexed: 12/13/2022]
Abstract
Mutations in nucleus-encoded mitochondrial aminoacyl-tRNA synthetases (mitaaRSs) lead to defects in mitochondrial translation affecting the expression and function of 13 subunits of the respiratory chain complex leading to diverse pathological conditions. Mutations in the FARS2 gene encoding human mitochondrial phenylalanyl-tRNA synthetase (HsmitPheRS) have been found to be associated with two different clinical representations, infantile Alpers encephalopathy and spastic paraplegia. Here we have studied three pathogenic mutants (Tyr144Cys, Ile329Thr, and Asp391Val) associated with Alpers encephalopathy to understand how these variants affect the biophysical properties of the enzyme. These mutants have already been reported to have reduced aminoacylation activity. Our study established that the mutants are significantly more thermolabile compared to the wild-type enzyme with reduced solubility in vitro. The presence of aggregation-prone insoluble HsmitPheRS variants could have a detrimental impact on organellar translation, and potentially impact normal mitochondrial function. © 2019 IUBMB Life, 71(8): 1141-1149, 2019 © 2019 IUBMB Life, 71(8):1141-1149, 2019.
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Affiliation(s)
- Shruti Chakraborty
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata, India
| | - Michael Ibba
- Department of Microbiology, The Ohio State University, Columbus, Ohio
| | - Rajat Banerjee
- Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology, University of Calcutta, Kolkata, India
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McCormick EM, Zolkipli-Cunningham Z, Falk MJ. Mitochondrial disease genetics update: recent insights into the molecular diagnosis and expanding phenotype of primary mitochondrial disease. Curr Opin Pediatr 2018; 30:714-724. [PMID: 30199403 PMCID: PMC6467265 DOI: 10.1097/mop.0000000000000686] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW Primary mitochondrial disease (PMD) is a genetically and phenotypically diverse group of inherited energy deficiency disorders caused by impaired mitochondrial oxidative phosphorylation (OXPHOS) capacity. Mutations in more than 350 genes in both mitochondrial and nuclear genomes are now recognized to cause primary mitochondrial disease following every inheritance pattern. Next-generation sequencing technologies have dramatically accelerated mitochondrial disease gene discovery and diagnostic yield. Here, we provide an up-to-date review of recently identified, novel mitochondrial disease genes and/or pathogenic variants that directly impair mitochondrial structure, dynamics, and/or function. RECENT FINDINGS A review of PubMed publications was performed from the past 12 months that identified 16 new PMD genes and/or pathogenic variants, and recognition of expanded phenotypes for a wide variety of mitochondrial disease genes. SUMMARY Broad-based exome sequencing has become the standard first-line diagnostic approach for PMD. This has facilitated more rapid and accurate disease identification, and greatly expanded understanding of the wide spectrum of potential clinical phenotypes. A comprehensive dual-genome sequencing approach to PMD diagnosis continues to improve diagnostic yield, advance understanding of mitochondrial physiology, and provide strong potential to develop precision therapeutics targeted to diverse aspects of mitochondrial disease pathophysiology.
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Affiliation(s)
- Elizabeth M. McCormick
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
| | - Zarazuela Zolkipli-Cunningham
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
| | - Marni J. Falk
- Mitochondrial Medicine Frontier Program, Division of Human Genetics, Department of Pediatrics, The Children’s Hospital of Philadelphia, PA 19104
- Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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31
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Almannai M, Wang J, Dai H, El-Hattab AW, Faqeih EA, Saleh MA, Al Asmari A, Alwadei AH, Aljadhai YI, AlHashem A, Tabarki B, Lines MA, Grange DK, Benini R, Alsaman AS, Mahmoud A, Katsonis P, Lichtarge O, Wong LJC. FARS2 deficiency; new cases, review of clinical, biochemical, and molecular spectra, and variants interpretation based on structural, functional, and evolutionary significance. Mol Genet Metab 2018; 125:281-291. [PMID: 30177229 DOI: 10.1016/j.ymgme.2018.07.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 07/25/2018] [Accepted: 07/25/2018] [Indexed: 02/07/2023]
Abstract
An increasing number of mitochondrial diseases are found to be caused by pathogenic variants in nuclear encoded mitochondrial aminoacyl-tRNA synthetases. FARS2 encodes mitochondrial phenylalanyl-tRNA synthetase (mtPheRS) which transfers phenylalanine to its cognate tRNA in mitochondria. Since the first case was reported in 2012, a total of 21 subjects with FARS2 deficiency have been reported to date with a spectrum of disease severity that falls between two phenotypes; early onset epileptic encephalopathy and a less severe phenotype characterized by spastic paraplegia. In this report, we present an additional 15 individuals from 12 families who are mostly Arabs homozygous for the pathogenic variant Y144C, which is associated with the more severe early onset phenotype. The total number of unique pathogenic FARS2 variants known to date is 21 including three different partial gene deletions reported in four individuals. Except for the large deletions, all variants but two (one in-frame deletion of one amino acid and one splice-site variant) are missense. All large deletions and the single splice-site variant are in trans with a missense variant. This suggests that complete loss of function may be incompatible with life. In this report, we also review structural, functional, and evolutionary significance of select FARS2 pathogenic variants reported here.
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Affiliation(s)
- Mohammed Almannai
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Julia Wang
- Medical Scientist Training Program and Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
| | - Hongzheng Dai
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Ayman W El-Hattab
- Division of Clinical Genetics and Metabolic Disorders, Pediatric Department, Tawam Hospital, Al-Ain, United Arab Emirates
| | - Eissa A Faqeih
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Mohammed A Saleh
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ali Al Asmari
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Ali H Alwadei
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Yaser I Aljadhai
- Department of Neuroimaging and Intervention, Medical Imaging Administration, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Amal AlHashem
- Department of Pediatric, Prince Sultan Medical Military City, Riyadh, Saudi Arabia; Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Brahim Tabarki
- Divisions of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Matthew A Lines
- Division of Metabolics and Newborn Screening, Children's Hospital of Eastern Ontario, Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Dorothy K Grange
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Ruba Benini
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Abdulaziz S Alsaman
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Adel Mahmoud
- Department of Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Panagiotis Katsonis
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Lee-Jun C Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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Sahai SK, Steiner RE, Au MG, Graham JM, Salamon N, Ibba M, Pierson TM. FARS2 mutations presenting with pure spastic paraplegia and lesions of the dentate nuclei. Ann Clin Transl Neurol 2018; 5:1128-1133. [PMID: 30250868 PMCID: PMC6144452 DOI: 10.1002/acn3.598] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/26/2018] [Accepted: 05/29/2018] [Indexed: 01/14/2023] Open
Abstract
Mutations in FARS2, the gene encoding the mitochondrial phenylalanine‐tRNA synthetase (mtPheRS), have been linked to a range of phenotypes including epileptic encephalopathy, developmental delay, and motor dysfunction. We report a 9‐year‐old boy with novel compound heterozygous variants of FARS2, presenting with a pure spastic paraplegia syndrome associated with bilateral signal abnormalities in the dentate nuclei. Exome sequencing identified a paternal nonsense variant (Q216X) lacking the catalytic core and anticodon‐binding regions, and a maternal missense variant (P136H) possessing partial enzymatic activity. This case confirms and expands the phenotype related to FARS2 mutations with regards to clinical presentation and neuroimaging findings.
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Affiliation(s)
- Supreet K Sahai
- Department of Neurology Cedars-Sinai Medical Center Los Angeles California
| | - Rebecca E Steiner
- Department of Microbiology Ohio State University Columbus Ohio 43210.,Center for RNA Biology Ohio State University Columbus Ohio 43210.,Ohio State Biochemistry Program Ohio State University Columbus Ohio 43210
| | - Margaret G Au
- Department of Pediatrics Cedars-Sinai Medical Center Los Angeles California
| | - John M Graham
- Department of Pediatrics Cedars-Sinai Medical Center Los Angeles California
| | - Noriko Salamon
- Department of Radiological Sciences David Geffen School of Medicine University of California Los Angeles Los Angeles California
| | - Michael Ibba
- Department of Microbiology Ohio State University Columbus Ohio 43210.,Center for RNA Biology Ohio State University Columbus Ohio 43210.,Ohio State Biochemistry Program Ohio State University Columbus Ohio 43210
| | - Tyler M Pierson
- Department of Neurology Cedars-Sinai Medical Center Los Angeles California.,Department of Pediatrics Cedars-Sinai Medical Center Los Angeles California.,Board of Governors Regenerative Medicine Institute Cedars-Sinai Medical Center Los Angeles California
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Vantroys E, Smet J, Vanlander AV, Vergult S, De Bruyne R, Roels F, Stepman H, Roeyers H, Menten B, Van Coster R. Severe hepatopathy and neurological deterioration after start of valproate treatment in a 6-year-old child with mitochondrial tryptophanyl-tRNA synthetase deficiency. Orphanet J Rare Dis 2018; 13:80. [PMID: 29783990 PMCID: PMC5963168 DOI: 10.1186/s13023-018-0822-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/08/2018] [Indexed: 01/08/2023] Open
Abstract
Background The first subjects with deficiency of mitochondrial tryptophanyl-tRNA synthetase (WARS2) were reported in 2017. Their clinical characteristics can be subdivided into three phenotypes (neonatal phenotype, severe infantile onset phenotype, Parkinson-like phenotype). Results Here, we report on a subject who presented with early developmental delay, motor weakness and intellectual disability and who was considered during several years as having a non-progressive encephalopathy. At the age of six years, she had an epileptic seizure which was treated with sodium valproate. In the months after treatment was started, she developed acute liver failure and severe progressive encephalopathy. Although valproate was discontinued, she died six months later. Spectrophotometric analysis of the oxidative phosphorylation complexes in liver revealed a deficient activity of complex III and low normal activities of the complexes I and IV. Activity staining in the BN-PAGE gel confirmed the low activities of complex I, III and IV and, in addition, showed the presence of a subcomplex of complex V. Histochemically, a mosaic pattern was seen in hepatocytes after cytochrome c oxidase staining. Using Whole Exome Sequencing two known pathogenic variants were detected in WARS2 (c.797delC, p.Pro266ArgfsTer10/ c.938 A > T, p.Lys313Met). Conclusion This is the first report of severe hepatopathy in a subject with WARS2 deficiency. The hepatopathy occurred soon after start of sodium valproate treatment. In the literature, valproate-induced hepatotoxicity was reported in the subjects with pathogenic mutations in POLG and TWNK. This case report illustrates that the course of the disease in the subjects with a mitochondrial defect can be non-progressive during several years. The subject reported here was first diagnosed as having cerebral palsy. Only after a mitochondriotoxic medication was started, the disease became progressive, and the diagnosis of a mitochondrial defect was made.
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Affiliation(s)
- Elise Vantroys
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Joél Smet
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Arnaud V Vanlander
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Sarah Vergult
- Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium
| | - Ruth De Bruyne
- Department of Pediatric Gastroenterology, Hepatology and Nutrition, Ghent University Hospital, Ghent, Belgium
| | - Frank Roels
- Department of Pathology, Ghent University Hospital, Ghent, Belgium
| | - Hedwig Stepman
- Department of Laboratory Medicine, Ghent University Hospital, Ghent, Belgium
| | - Herbert Roeyers
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | - Björn Menten
- Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium
| | - Rudy Van Coster
- Department of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium.
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Finsterer J, Scorza CA, Scorza FA. Phenotypic spectrum of FARS2-deficiency. Mol Genet Metab Rep 2018; 14:41-42. [PMID: 29326872 PMCID: PMC5758838 DOI: 10.1016/j.ymgmr.2017.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 11/18/2017] [Accepted: 11/18/2017] [Indexed: 12/05/2022] Open
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