1
|
Jacob M, Brugger M, Andres S, Wagner M, Graf E, Berutti R, Tilch E, Pavlov M, Mayerhanser K, Hoefele J, Meitinger T, Winkelmann J, Brunet T. Genome Sequencing for Cases Unsolved by Exome Sequencing: Identifying a Single-Exon Deletion in TBCK in a Case from 30 Years Ago. Neuropediatrics 2024; 55:260-264. [PMID: 38547905 DOI: 10.1055/s-0044-1782680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
In patients with neurodevelopmental disorders (NDDs), exome sequencing (ES), the diagnostic gold standard, reveals an underlying monogenic condition in only approximately 40% of cases. We report the case of a female patient with profound NDD who died 30 years ago at the age of 3 years and for whom genome sequencing (GS) now identified a single-exon deletion in TBCK previously missed by ExomeDepth, the copy number variation (CNV) detection algorithm in ES.Deoxyribonucleic acid (DNA) was extracted from frozen muscle tissue of the index patient and the parents' blood. Genome data were analyzed for structural variants and single nucleotide variants (SUVs)/indels as part of the Bavarian Genomes consortium project.Biallelic variants in TBCK, which are linked to the autosomal recessive disorder TBCK syndrome, were detected in the affected individual: a novel frameshift variant and a deletion of exon 23, previously established as common but underrecognized pathogenic variant in individuals with TBCK syndrome. While in the foregoing ES analysis, calling algorithms for (SNVs)/indels were able to identify the frameshift variant, ExomeDepth failed to call the intragenic deletion.Our case illustrates the added value of GS for the detection of single-exon deletions for which calling from ES data remains challenging and confirms that the deletion of exon 23 in TBCK may be underdiagnosed in patients with NDDs. Furthermore, it shows the importance of "molecular or genetic autopsy" allowing genetic risk counseling for family members as well as the end of a diagnostic odyssey of 30 years.
Collapse
Affiliation(s)
- Maureen Jacob
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Melanie Brugger
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Stephanie Andres
- Center of Human Genetics and Laboratory Diagnostics, Martinsried, Germany
| | - Matias Wagner
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Elisabeth Graf
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Riccardo Berutti
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Erik Tilch
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Martin Pavlov
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
| | - Katharina Mayerhanser
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Thomas Meitinger
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
| | - Juliane Winkelmann
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Theresa Brunet
- Institute of Human Genetics, Klinikum rechts der Isar, Technical University of Munich, School of Medicine and Health, Munich, Germany
- Bavarian Genomes Network for Rare Disorders
- Dr. v. Hauner Children's Hospital, Department of Pediatric Neurology and Developmental Medicine, LMU - University of Munich, Munich, Germany
| |
Collapse
|
2
|
Nair D, Diaz-Rosado A, Varella-Branco E, Ramos I, Black A, Angireddy R, Park J, Murali S, Yoon A, Ciesielski B, O’Brien WT, Passos-Bueno MR, Bhoj E. Heterozygous variants in TBCK cause a mild neurologic syndrome in humans and mice. Am J Med Genet A 2023; 191:2508-2517. [PMID: 37353954 PMCID: PMC10524953 DOI: 10.1002/ajmg.a.63320] [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: 12/23/2022] [Revised: 05/15/2023] [Accepted: 05/26/2023] [Indexed: 06/25/2023]
Abstract
TBCK-related encephalopathy is a rare pediatric neurodegenerative disorder caused by biallelic loss-of-function variants in the TBCK gene. After receiving anecdotal reports of neurologic phenotypes in both human and mouse TBCK heterozygotes, we quantified if TBCK haploinsufficiency causes a phenotype in mice and humans. Using the tbck+/- mouse model, we performed a battery of behavioral assays and mTOR pathway analysis to investigate potential alterations in neurophysiology. We conducted as well a phenome-wide association study (PheWAS) analysis in a large adult biobank to determine the presence of potential phenotypes associated to this variant. The tbck+/- mouse model demonstrates a reduction of exploratory behavior in animals with significant sex and genotype interactions. The concurrent PheWAS analysis of 10,900 unrelated individuals showed that patients with one copy of a TBCK loss-of-function allele had a significantly higher rate of acquired toe and foot deformities, likely indicative of a mild peripheral neuropathy phenotype. This study presents an example of what may be the underappreciated occurrence of mild neurogenic symptoms in heterozygote individuals of recessive neurogenetic syndromes.
Collapse
Affiliation(s)
- Divya Nair
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Abdias Diaz-Rosado
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Elisa Varella-Branco
- Centro de Estudos do Genoma Humano e Células-Tronco, Universidade de São Paulo, São Paulo, Brazil
| | - Igor Ramos
- Centro de Estudos do Genoma Humano e Células-Tronco, Universidade de São Paulo, São Paulo, Brazil
| | - Aaron Black
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Rajesh Angireddy
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Joseph Park
- Department of Physiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Svathi Murali
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
- Department of Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew Yoon
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| | - Brianna Ciesielski
- ITMAT, University of Pennsylvania, School of Medicine, Philadelphia, PA, 19104 USA
| | - W. Timothy O’Brien
- ITMAT, University of Pennsylvania, School of Medicine, Philadelphia, PA, 19104 USA
| | | | - Elizabeth Bhoj
- Department of Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA, 19104 USA
| |
Collapse
|
3
|
Durham EL, Angireddy R, Black A, Melendez-Perez A, Smith S, Gonzalez EM, Navarro KG, Díaz A, Bhoj EJK, Katsura KA. TBCK syndrome: a rare multi-organ neurodegenerative disease. Trends Mol Med 2023; 29:783-785. [PMID: 37455236 PMCID: PMC10868401 DOI: 10.1016/j.molmed.2023.06.009] [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: 05/18/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/18/2023]
Abstract
TBCK syndrome is an autosomal recessive disorder primarily characterized by global developmental delay, hypotonia, abnormal magnetic resonance imaging (MRI), and distinctive craniofacial phenotypes. High variability is observed among affected individuals and their corresponding variants, making clinical diagnosis challenging. Here, we discuss recent breakthroughs in clinical considerations, TBCK function, and therapeutic development.
Collapse
Affiliation(s)
- Emily L Durham
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA
| | - Rajesh Angireddy
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA
| | - Aaron Black
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA
| | - Ashley Melendez-Perez
- Division of Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Sarina Smith
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA
| | - Elizabeth M Gonzalez
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA; Division of Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Kristen G Navarro
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA
| | - Abdias Díaz
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA; Division of Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Elizabeth J K Bhoj
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA; Division of Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
| | - Kaitlin A Katsura
- Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, PA, USA; Department of Orofacial Sciences and Program in Craniofacial Biology, University of California, San Francisco, San Francisco, CA, USA.
| |
Collapse
|
4
|
Schuhmacher JS, Tom Dieck S, Christoforidis S, Landerer C, Davila Gallesio J, Hersemann L, Seifert S, Schäfer R, Giner A, Toth-Petroczy A, Kalaidzidis Y, Bohnsack KE, Bohnsack MT, Schuman EM, Zerial M. The Rab5 effector FERRY links early endosomes with mRNA localization. Mol Cell 2023; 83:1839-1855.e13. [PMID: 37267905 DOI: 10.1016/j.molcel.2023.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/06/2022] [Accepted: 05/08/2023] [Indexed: 06/04/2023]
Abstract
Localized translation is vital to polarized cells and requires precise and robust distribution of different mRNAs and ribosomes across the cell. However, the underlying molecular mechanisms are poorly understood and important players are lacking. Here, we discovered a Rab5 effector, the five-subunit endosomal Rab5 and RNA/ribosome intermediary (FERRY) complex, that recruits mRNAs and ribosomes to early endosomes through direct mRNA-interaction. FERRY displays preferential binding to certain groups of transcripts, including mRNAs encoding mitochondrial proteins. Deletion of FERRY subunits reduces the endosomal localization of transcripts in cells and has a significant impact on mRNA levels. Clinical studies show that genetic disruption of FERRY causes severe brain damage. We found that, in neurons, FERRY co-localizes with mRNA on early endosomes, and mRNA loaded FERRY-positive endosomes are in close proximity of mitochondria. FERRY thus transforms endosomes into mRNA carriers and plays a key role in regulating mRNA distribution and transport.
Collapse
Affiliation(s)
- Jan S Schuhmacher
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Susanne Tom Dieck
- Max Planck Institute for Brain Research, Max-von-Laue-Str. 4, 60438 Frankfurt am Main, Germany
| | - Savvas Christoforidis
- Biomedical Research Institute, Foundation for Research and Technology, 45110 Ioannina, Greece; Laboratory of Biological Chemistry, Department of Medicine, School of Health Sciences, University of Ioannina, 45110 Ioannina, Greece
| | - Cedric Landerer
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Jimena Davila Gallesio
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Lena Hersemann
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Sarah Seifert
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Ramona Schäfer
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Angelika Giner
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Agnes Toth-Petroczy
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Yannis Kalaidzidis
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Humboldtallee 23, 37073 Göttingen, Germany; Göttingen Centre for Molecular Biosciences, University of Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany; Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Max-von-Laue-Str. 4, 60438 Frankfurt am Main, Germany
| | - Marino Zerial
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany; Center for Systems Biology Dresden, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
| |
Collapse
|
5
|
Quentin D, Schuhmacher JS, Klink BU, Lauer J, Shaikh TR, Huis In 't Veld PJ, Welp LM, Urlaub H, Zerial M, Raunser S. Structural basis of mRNA binding by the human FERRY Rab5 effector complex. Mol Cell 2023; 83:1856-1871.e9. [PMID: 37267906 DOI: 10.1016/j.molcel.2023.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/05/2022] [Accepted: 05/05/2023] [Indexed: 06/04/2023]
Abstract
The pentameric FERRY Rab5 effector complex is a molecular link between mRNA and early endosomes in mRNA intracellular distribution. Here, we determine the cryo-EM structure of human FERRY. It reveals a unique clamp-like architecture that bears no resemblance to any known structure of Rab effectors. A combination of functional and mutational studies reveals that while the Fy-2 C-terminal coiled-coil acts as binding region for Fy-1/3 and Rab5, both coiled-coils and Fy-5 concur to bind mRNA. Mutations causing truncations of Fy-2 in patients with neurological disorders impair Rab5 binding or FERRY complex assembly. Thus, Fy-2 serves as a binding hub connecting all five complex subunits and mediating the binding to mRNA and early endosomes via Rab5. Our study provides mechanistic insights into long-distance mRNA transport and demonstrates that the particular architecture of FERRY is closely linked to a previously undescribed mode of RNA binding, involving coiled-coil domains.
Collapse
Affiliation(s)
- Dennis Quentin
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Jan S Schuhmacher
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Björn U Klink
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany; Center for Soft Nanoscience and Institute of Molecular Physics and Biophysics, 48149 Münster, Germany
| | - Jeni Lauer
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Tanvir R Shaikh
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Pim J Huis In 't Veld
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany
| | - Luisa M Welp
- Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany
| | - Henning Urlaub
- Max Planck Institute for Multidisciplinary Sciences, 37077 Göttingen, Germany; Institute of Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Marino Zerial
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, 44227 Dortmund, Germany.
| |
Collapse
|
6
|
Slater K, Williams JA, Schofield PN, Russell S, Pendleton SC, Karwath A, Fanning H, Ball S, Hoehndorf R, Gkoutos GV. Klarigi: Characteristic explanations for semantic biomedical data. Comput Biol Med 2023; 153:106425. [PMID: 36638616 DOI: 10.1016/j.compbiomed.2022.106425] [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: 08/30/2022] [Revised: 12/04/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022]
Abstract
Annotation of biomedical entities with ontology classes provides for formal semantic analysis and mobilisation of background knowledge in determining their relationships. To date, enrichment analysis has been routinely employed to identify classes that are over-represented in annotations across sets of groups, such as biosample gene expression profiles or patient phenotypes, and is useful for a range of tasks including differential diagnosis and causative variant prioritisation. These approaches, however, usually consider only univariate relationships, make limited use of the semantic features of ontologies, and provide limited information and evaluation of the explanatory power of both singular and grouped candidate classes. Moreover, they are not designed to solve the problem of deriving cohesive, characteristic, and discriminatory sets of classes for entity groups. We have developed a new tool, called Klarigi, which introduces multiple scoring heuristics for identification of classes that are both compositional and discriminatory for groups of entities annotated with ontology classes. The tool includes a novel algorithm for derivation of multivariable semantic explanations for entity groups, makes use of semantic inference through live use of an ontology reasoner, and includes a classification method for identifying the discriminatory power of candidate sets, in addition to significance testing apposite to traditional enrichment approaches. We describe the design and implementation of Klarigi, including its scoring and explanation determination methods, and evaluate its use in application to two test cases with clinical significance, comparing and contrasting methods and results with literature-based and enrichment analysis methods. We demonstrate that Klarigi produces characteristic and discriminatory explanations for groups of biomedical entities in two settings. We also show that these explanations recapitulate and extend the knowledge held in existing biomedical databases and literature for several diseases. We conclude that Klarigi provides a distinct and valuable perspective on biomedical datasets when compared with traditional enrichment methods, and therefore constitutes a new method by which biomedical datasets can be explored, contributing to improved insight into semantic data.
Collapse
Affiliation(s)
- Karin Slater
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, UK; Institute of Translational Medicine, University Hospitals Birmingham, NHS Foundation Trust, UK; MRC Health Data Research UK (HDR UK), Midlands, UK; University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK.
| | - John A Williams
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, UK; Institute of Translational Medicine, University Hospitals Birmingham, NHS Foundation Trust, UK; University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Paul N Schofield
- Department of Physiology, Development, and Neuroscience, University of Cambridge, UK
| | - Sophie Russell
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, UK
| | - Samantha C Pendleton
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, UK
| | - Andreas Karwath
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, UK; Institute of Translational Medicine, University Hospitals Birmingham, NHS Foundation Trust, UK; MRC Health Data Research UK (HDR UK), Midlands, UK; University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Hilary Fanning
- Institute of Translational Medicine, University Hospitals Birmingham, NHS Foundation Trust, UK; University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Simon Ball
- Institute of Translational Medicine, University Hospitals Birmingham, NHS Foundation Trust, UK; University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| | - Robert Hoehndorf
- Computer, Electrical and Mathematical Sciences & Engineering Division, Computational Bioscience Research Center, King Abdullah University of Science and Technology, UK
| | - Georgios V Gkoutos
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, UK; Institute of Translational Medicine, University Hospitals Birmingham, NHS Foundation Trust, UK; NIHR Experimental Cancer Medicine Centre, UK; NIHR Surgical Reconstruction and Microbiology Research Centre, UK; NIHR Biomedical Research Centre, UK; MRC Health Data Research UK (HDR UK), Midlands, UK; University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK
| |
Collapse
|
7
|
Sabanathan S, Gulhane D, Mankad K, Davison J, Ong MT, Phadke R, Robinson R, Spiller M, Wakeling E, Ramdas S, Brady AF, Balasubramanian M, Munot P. Expanding the phenotype of children presenting with hypoventilation with biallelic TBCK pathogenic variants and literature review. Neuromuscul Disord 2023; 33:50-57. [PMID: 36522252 DOI: 10.1016/j.nmd.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022]
Abstract
Individuals with biallelic TBCK pathogenic variants present in infancy with distinctive facial features, profound hypotonia, severe intellectual impairment and epilepsy. Although rare, it may mimic other neurogenetic disorders leading to extensive investigations. Improved understanding of the clinical phenotype can support early monitoring of complications due to respiratory insufficiency. We present six individuals who were found to have pathogenic biallelic TBCK variants. The clinico-radiological and diagnostic records were reviewed. Five individuals were diagnosed with hypoventilation, requiring respiratory support, highlighting the need for early respiratory surveillance. Characteristic brain imaging in our cohort included periventricular leukomalacia-like changes. We recommend screening for TBCK in hypotonic children with periventricular leukomalacia-like changes, particularly in the absence of prematurity.
Collapse
Affiliation(s)
| | - Deepti Gulhane
- Department of Neurology, Great Ormond Street Hospital NHS Trust, London, UK
| | - Kshitij Mankad
- Department of neuroradiology, Great Ormond Street Hospital NHS Trust, London, UK
| | - James Davison
- Department of Metabolic Medicine, Great Ormond Street Hospital NHS Trust, London, UK
| | - Min Tsui Ong
- Department of Neurology, Sheffield Children's Hospital NHS Foundation Trust, London, UK
| | - Rahul Phadke
- Department of Neuropathology, Institute of Neurology, Queen Square, London, UK
| | - Robert Robinson
- Department of Neurology, Great Ormond Street Hospital NHS Trust, London, UK
| | - Michael Spiller
- Sheffield Diagnostic Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Emma Wakeling
- North East Thames Regional Genetic Service, Great Ormond Street Hospital NHS Trust, London, UK
| | - Sithara Ramdas
- MDUK neuromuscular centre, Department of Paediatrics, University of Oxford, UK; Department of Paediatric Neurology, John Radcliffe Hospital, Oxford, UK
| | - Angela F Brady
- North West Thames Regional Genetics Service, London North West University Healthcare NHS Trust, Northwick Park Hospital, Middlesex, HA1 3UJ, UK
| | - Meena Balasubramanian
- Department of Oncology & Metabolism, University of Sheffield, Sheffield, UK; Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK.
| | - Pinki Munot
- Department of Neurology, Great Ormond Street Hospital NHS Trust, London, UK.
| |
Collapse
|
8
|
Ververi A, Zagaglia S, Menzies L, Baptista J, Caswell R, Baulac S, Ellard S, Lynch S, Jacques TS, Chawla MS, Heier M, Kulseth MA, Mero IL, Våtevik AK, Kraoua I, Ben Rhouma H, Ben Younes T, Miladi Z, Ben Youssef Turki I, Jones WD, Clement E, Eltze C, Mankad K, Merve A, Parker J, Hoskins B, Pressler R, Sudhakar S, DeVile C, Homfray T, Kaliakatsos M, Robinson R, Keim SMB, Habibi I, Reymond A, Sisodiya SM, Hurst JA. Germline homozygous missense DEPDC5 variants cause severe refractory early-onset epilepsy, macrocephaly and bilateral polymicrogyria. Hum Mol Genet 2022; 32:580-594. [PMID: 36067010 PMCID: PMC9896472 DOI: 10.1093/hmg/ddac225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 08/16/2022] [Accepted: 08/31/2022] [Indexed: 02/07/2023] Open
Abstract
DEPDC5 (DEP Domain-Containing Protein 5) encodes an inhibitory component of the mammalian target of rapamycin (mTOR) pathway and is commonly implicated in sporadic and familial focal epilepsies, both non-lesional and in association with focal cortical dysplasia. Germline pathogenic variants are typically heterozygous and inactivating. We describe a novel phenotype caused by germline biallelic missense variants in DEPDC5. Cases were identified clinically. Available records, including magnetic resonance imaging and electroencephalography, were reviewed. Genetic testing was performed by whole exome and whole-genome sequencing and cascade screening. In addition, immunohistochemistry was performed on skin biopsy. The phenotype was identified in nine children, eight of which are described in detail herein. Six of the children were of Irish Traveller, two of Tunisian and one of Lebanese origin. The Irish Traveller children shared the same DEPDC5 germline homozygous missense variant (p.Thr337Arg), whereas the Lebanese and Tunisian children shared a different germline homozygous variant (p.Arg806Cys). Consistent phenotypic features included extensive bilateral polymicrogyria, congenital macrocephaly and early-onset refractory epilepsy, in keeping with other mTOR-opathies. Eye and cardiac involvement and severe neutropenia were also observed in one or more patients. Five of the children died in infancy or childhood; the other four are currently aged between 5 months and 6 years. Skin biopsy immunohistochemistry was supportive of hyperactivation of the mTOR pathway. The clinical, histopathological and genetic evidence supports a causal role for the homozygous DEPDC5 variants, expanding our understanding of the biology of this gene.
Collapse
Affiliation(s)
| | | | | | | | - Richard Caswell
- Exeter Genomics Laboratory, Royal Devon University Healthcare NHS Foundation Trust, Exeter, UK
| | - Stephanie Baulac
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, F-75013 Paris, France
| | - Sian Ellard
- Exeter Genomics Laboratory, Royal Devon University Healthcare NHS Foundation Trust, Exeter, UK
| | - Sally Lynch
- Academic Centre on Rare Diseases, University College Dublin School of Medicine and Medical Science, Dublin, Ireland,Department of Clinical Genetics, Children's Health Ireland (CHI) at Crumlin, Dublin, Ireland
| | | | - Thomas S Jacques
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK,Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | | | - Martin Heier
- Department of Clinical Neuroscience for Children, Oslo University Hospital, Oslo, Norway
| | - Mari Ann Kulseth
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Inger-Lise Mero
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | | | - Ichraf Kraoua
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia. Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Hanene Ben Rhouma
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia. Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Thouraya Ben Younes
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia. Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Zouhour Miladi
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia. Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Ilhem Ben Youssef Turki
- Research Laboratory LR18SP04, Department of Child and Adolescent Neurology, National Institute Mongi Ben Hmida of Neurology, Tunis, Tunisia. Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Wendy D Jones
- Department of Clinical Genetics & Genomic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Emma Clement
- Department of Clinical Genetics & Genomic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Christin Eltze
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Kshitij Mankad
- Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Ashirwad Merve
- Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Jennifer Parker
- North Thames Genomic Laboratory Hub, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Bethan Hoskins
- North Thames Genomic Laboratory Hub, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Ronit Pressler
- Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Sniya Sudhakar
- Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Catherine DeVile
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Tessa Homfray
- SW Thames Regional Genetics Service, St George's Hospital, St George's University of London, London, UK
| | - Marios Kaliakatsos
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Ponnudas (Prab) Prabhakar
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Robert Robinson
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | | | - Imen Habibi
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Alexandre Reymond
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Sanjay M Sisodiya
- To whom correspondence should be addressed at: Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, UK.
| | | |
Collapse
|
9
|
Kim WD, Wilson-Smillie MLDM, Thanabalasingam A, Lefrancois S, Cotman SL, Huber RJ. Autophagy in the Neuronal Ceroid Lipofuscinoses (Batten Disease). Front Cell Dev Biol 2022; 10:812728. [PMID: 35252181 PMCID: PMC8888908 DOI: 10.3389/fcell.2022.812728] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/24/2022] [Indexed: 12/22/2022] Open
Abstract
The neuronal ceroid lipofuscinoses (NCLs), also referred to as Batten disease, are a family of neurodegenerative diseases that affect all age groups and ethnicities around the globe. At least a dozen NCL subtypes have been identified that are each linked to a mutation in a distinct ceroid lipofuscinosis neuronal (CLN) gene. Mutations in CLN genes cause the accumulation of autofluorescent lipoprotein aggregates, called ceroid lipofuscin, in neurons and other cell types outside the central nervous system. The mechanisms regulating the accumulation of this material are not entirely known. The CLN genes encode cytosolic, lysosomal, and integral membrane proteins that are associated with a variety of cellular processes, and accumulated evidence suggests they participate in shared or convergent biological pathways. Research across a variety of non-mammalian and mammalian model systems clearly supports an effect of CLN gene mutations on autophagy, suggesting that autophagy plays an essential role in the development and progression of the NCLs. In this review, we summarize research linking the autophagy pathway to the NCLs to guide future work that further elucidates the contribution of altered autophagy to NCL pathology.
Collapse
Affiliation(s)
- William D. Kim
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | | | - Aruban Thanabalasingam
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON, Canada
| | - Stephane Lefrancois
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique, Laval, QC, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre D'Excellence en Recherche sur Les Maladies Orphelines–Fondation Courtois (CERMO-FC), Université Du Québec à Montréal (UQAM), Montréal, QC, Canada
| | - Susan L. Cotman
- Department of Neurology, Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Harvard Medical School, Boston, MA, United States
| | - Robert J. Huber
- Department of Biology, Trent University, Peterborough, ON, Canada
| |
Collapse
|
10
|
Reddy N, Doyle M, Hanagandi P, Taranath A, Dahmoush H, Krishnan P, Oztekin O, Boltshauser E, Shroff M, Mankad K. Neuroradiological Mimics of Periventricular Leukomalacia. J Child Neurol 2022; 37:151-167. [PMID: 34937403 DOI: 10.1177/08830738211026052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
AIM Periventricular leukomalacia (PVL) is a term reserved to describe white matter injury in the premature brain. In this review article, the authors highlight the common and rare pathologies mimicking the chronic stage of PVL and propose practical clinico-radiological criteria that would aid in diagnosis and management. METHODS AND RESULTS The authors first describe the typical brain MRI (magnetic resonance imaging) features of PVL. Based on their clinical presentation, pathologic entities and their neuroimaging findings were clustered into distinct categories. Three clinical subgroups were identified: healthy children, children with stable/nonprogressive neurological disorder, and those with progressive neurological disorder. The neuroradiological discriminators are described in each subgroup with relevant differential diagnoses. The mimics were broadly classified into normal variants, acquired, and inherited disorders. CONCLUSIONS The term "PVL" should be used appropriately as it reflects its pathomechanism. The phrase "white matter injury of prematurity" or "brain injury of prematurity" is more specific. Discrepancies in imaging and clinical presentation must be tread with caution and warrant further investigations to exclude other possibilities.
Collapse
Affiliation(s)
- Nihaal Reddy
- Rainbow Children's Hospital and Tenet Diagnostics, Hyderabad, India
| | - Mary Doyle
- Department of Paediatric Neurology, Great Ormond Street Hospital, London, UK
| | - Prasad Hanagandi
- Department of Neuroradiology, King Abdulaziz Medical City, Riyadh Ministry of National Guard Health Affairs, Saudi Arabia
| | - Ajay Taranath
- Department of Radiology, Women's and Children's Hospital, Adelaide, Australia
| | - Hisham Dahmoush
- Department of Radiology, Lucile Packard Children's Hospital, Stanford, CA, USA
| | - Pradeep Krishnan
- Department of Pediatric Neuroradiology, The Hospital for Sick Children, Toronto, Canada
| | - Ozgur Oztekin
- Tepecik Research and Education Hospital, Health Science University, Izmir, Turkey
| | - Eugen Boltshauser
- Department of Pediatric Neurology, University Children's Hospital, Zurich, Steinwiesstrasse, Switzerland
| | - Manohar Shroff
- Department of Pediatric Neuroradiology, The Hospital for Sick Children, Toronto, Canada
| | - Kshitij Mankad
- Department of Radiology, Great Ormond Street Hospital, London, UK
| |
Collapse
|
11
|
Moreira DDP, Suzuki AM, Silva ALTE, Varella-Branco E, Meneghetti MCZ, Kobayashi GS, Fogo M, Ferrari MDFR, Cardoso RR, Lourenço NCV, Griesi-Oliveira K, Zachi EC, Bertola DR, Weinmann KDS, de Lima MA, Nader HB, Sertié AL, Passos-Bueno MR. Neuroprogenitor Cells From Patients With TBCK Encephalopathy Suggest Deregulation of Early Secretory Vesicle Transport. Front Cell Neurosci 2022; 15:803302. [PMID: 35095425 PMCID: PMC8793280 DOI: 10.3389/fncel.2021.803302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
Biallelic pathogenic variants in TBCK cause encephaloneuropathy, infantile hypotonia with psychomotor retardation, and characteristic facies 3 (IHPRF3). The molecular mechanisms underlying its neuronal phenotype are largely unexplored. In this study, we reported two sisters, who harbored biallelic variants in TBCK and met diagnostic criteria for IHPRF3. We provided evidence that TBCK may play an important role in the early secretory pathway in neuroprogenitor cells (iNPC) differentiated from induced pluripotent stem cells (iPSC). Lack of functional TBCK protein in iNPC is associated with impaired endoplasmic reticulum-to-Golgi vesicle transport and autophagosome biogenesis, as well as altered cell cycle progression and severe impairment in the capacity of migration. Alteration in these processes, which are crucial for neurogenesis, neuronal migration, and cytoarchitecture organization, may represent an important causative mechanism of both neurodevelopmental and neurodegenerative phenotypes observed in IHPRF3. Whether reduced mechanistic target of rapamycin (mTOR) signaling is secondary to impaired TBCK function over other secretory transport regulators still needs further investigation.
Collapse
Affiliation(s)
- Danielle de Paula Moreira
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Angela May Suzuki
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | | | - Elisa Varella-Branco
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | | | - Gerson Shigeru Kobayashi
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Mariana Fogo
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
- Instituto de Ensino e Pesquisa Albert Einstein, Albert Einstein Hospital, São Paulo, Brazil
| | | | - Rafaela Regina Cardoso
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Naila Cristina Vilaça Lourenço
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Karina Griesi-Oliveira
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
- Instituto de Ensino e Pesquisa Albert Einstein, Albert Einstein Hospital, São Paulo, Brazil
| | - Elaine Cristina Zachi
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Débora Romeo Bertola
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
- Instituto da Criança do Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Karina de Souza Weinmann
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Marcelo Andrade de Lima
- Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Helena Bonciani Nader
- Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Andrea Laurato Sertié
- Instituto de Ensino e Pesquisa Albert Einstein, Albert Einstein Hospital, São Paulo, Brazil
| | - Maria Rita Passos-Bueno
- Centro de Pesquisas Sobre o Genoma Humano e Células-Tronco, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
- *Correspondence: Maria Rita Passos-Bueno,
| |
Collapse
|
12
|
Tintos-Hernández JA, Santana A, Keller KN, Ortiz-González XR. Lysosomal dysfunction impairs mitochondrial quality control and is associated with neurodegeneration in TBCK encephaloneuronopathy. Brain Commun 2021; 3:fcab215. [PMID: 34816123 PMCID: PMC8603245 DOI: 10.1093/braincomms/fcab215] [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: 08/03/2020] [Revised: 06/02/2021] [Accepted: 06/07/2021] [Indexed: 11/14/2022] Open
Abstract
Biallelic variants in the TBCK gene cause intellectual disability with remarkable clinical variability, ranging from static encephalopathy to progressive neurodegeneration (TBCK-Encephaloneuronopathy). The biological factors underlying variable disease penetrance remain unknown. Since previous studies had suggested aberrant autophagy, we tested whether mitophagy and mitochondrial function are altered in TBCK−/− fibroblasts derived from patients exhibiting variable clinical severity. Our data show significant accumulation of mitophagosomes, reduced mitochondrial respiratory capacity and mitochondrial DNA content, suggesting impaired mitochondrial quality control. Furthermore, the degree of mitochondrial dysfunction correlates with a neurodegenerative clinical course. Since mitophagy ultimately depends on lysosomal degradation, we also examined lysosomal function. Our data show that lysosomal proteolytic function is significantly reduced in TBCK−/− fibroblasts. Moreover, acidifying lysosomal nanoparticles rescue the mitochondrial respiratory defects in fibroblasts, suggesting impaired mitochondrial quality control secondary to lysosomal dysfunction. Our data provide insight into the disease mechanisms of TBCK Encephaloneuronopathy and the potential relevance of mitochondrial function as a biomarker beyond primary mitochondrial disorders. It also supports the benefit of lysosomal acidification strategies for disorders of impaired lysosomal degradation affecting mitochondrial quality control.
Collapse
Affiliation(s)
- Jesus A Tintos-Hernández
- Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Adrian Santana
- Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Kierstin N Keller
- Department of Genetics, Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Xilma R Ortiz-González
- Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Epilepsy Neurogenetics Initiative and Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
13
|
Miyamoto S, Kato M, Hiraide T, Shiohama T, Goto T, Hojo A, Ebata A, Suzuki M, Kobayashi K, Chong PF, Kira R, Matsushita HB, Ikeda H, Hoshino K, Matsufuji M, Moriyama N, Furuyama M, Yamamoto T, Nakashima M, Saitsu H. Comprehensive genetic analysis confers high diagnostic yield in 16 Japanese patients with corpus callosum anomalies. J Hum Genet 2021; 66:1061-1068. [PMID: 33958710 DOI: 10.1038/s10038-021-00932-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/12/2021] [Accepted: 04/16/2021] [Indexed: 12/24/2022]
Abstract
Corpus callosum anomalies (CCA) is a common congenital brain anomaly with various etiologies. Although one of the most important etiologies is genetic factors, the genetic background of CCA is heterogenous and diverse types of variants are likely to be causative. In this study, we analyzed 16 Japanese patients with corpus callosum anomalies to delineate clinical features and the genetic background of CCAs. We observed the common phenotypes accompanied by CCAs: intellectual disability (100%), motor developmental delay (93.8%), seizures (60%), and facial dysmorphisms (50%). Brain magnetic resonance imaging showed colpocephaly (enlarged posterior horn of the lateral ventricles, 84.6%) and enlarged supracerebellar cistern (41.7%). Whole exome sequencing revealed genetic alterations in 9 of the 16 patients (56.3%), including 8 de novo alterations (2 copy number variants and variants in ARID1B, CDK8, HIVEP2, and TCF4) and a recessive variant of TBCK. De novo ARID1B variants were identified in three unrelated individuals, suggesting that ARID1B variants are major genetic causes of CCAs. A de novo TCF4 variant and somatic mosaic deletion at 18q21.31-qter encompassing TCF4 suggest an association of TCF4 abnormalities with CCAs. This study, which analyzes CCA patients usung whole exome sequencing, demonstrates that comprehensive genetic analysis would be useful for investigating various causal variants of CCAs.
Collapse
Affiliation(s)
- Sachiko Miyamoto
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Takuya Hiraide
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Tadashi Shiohama
- Department of Pediatrics, Graduated School of Medicine, Chiba University, Chiba, Japan
| | - Tomohide Goto
- Division of Neurology, Kanagawa Children's Medical Center, Yokohama, Japan
| | - Akira Hojo
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Akio Ebata
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Manabu Suzuki
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Kozue Kobayashi
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
| | - Pin Fee Chong
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan
| | - Ryutaro Kira
- Department of Pediatric Neurology, Fukuoka Children's Hospital, Fukuoka, Japan
| | | | - Hiroko Ikeda
- Department of Pediatrics, National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Kyoko Hoshino
- Segawa Memorial Neurological Clinic for Children, Tokyo, Japan
| | - Mayumi Matsufuji
- Department of Pediatrics, Minami Kyushu National Hospital, Aira, Japan
| | - Nobuko Moriyama
- Department of Pediatrics, Hitachi, Ltd., Hitachinaka General Hospital, Hitachinaka, Japan
| | - Masayuki Furuyama
- Department of Pediatrics, Okitama Public General Hospital, Yamagata, Japan
| | - Tatsuya Yamamoto
- Department of Pediatrics, Hirosaki University School of Medicine, Hirosaki, Japan
| | - Mitsuko Nakashima
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan.
| |
Collapse
|
14
|
Naess K, Bruhn H, Stranneheim H, Freyer C, Wibom R, Mourier A, Engvall M, Nennesmo I, Lesko N, Wredenberg A, Wedell A, von Döbeln U. Clinical Presentation, Genetic Etiology, and Coenzyme Q10 Levels in 55 Children with Combined Enzyme Deficiencies of the Mitochondrial Respiratory Chain. J Pediatr 2021; 228:240-251.e2. [PMID: 32827528 DOI: 10.1016/j.jpeds.2020.08.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/10/2020] [Accepted: 08/10/2020] [Indexed: 12/20/2022]
Abstract
OBJECTIVES To evaluate the clinical symptoms and biochemical findings and establish the genetic etiology in a cohort of pediatric patients with combined deficiencies of the mitochondrial respiratory chain complexes. STUDY DESIGN Clinical and biochemical data were collected from 55 children. All patients were subjected to sequence analysis of the entire mitochondrial genome, except when the causative mutations had been identified based on the clinical picture. Whole exome sequencing/whole genome sequencing (WES/WGS) was performed in 32 patients. RESULTS Onset of disease was generally early in life (median age, 6 weeks). The most common symptoms were muscle weakness, hypotonia, and developmental delay/intellectual disability. Nonneurologic symptoms were frequent. Disease causing mutations were found in 20 different nuclear genes, and 7 patients had mutations in mitochondrial DNA. Causative variants were found in 18 of the 32 patients subjected to WES/WGS. Interestingly, many patients had low levels of coenzyme Q10 in muscle, irrespective of genetic cause. CONCLUSIONS Children with combined enzyme defects display a diversity of clinical symptoms with varying age of presentation. We established the genetic diagnosis in 35 of the 55 patients (64%). The high diagnostic yield was achieved by the introduction of massive parallel sequencing, which also revealed novel genes and enabled elucidation of new disease mechanisms.
Collapse
Affiliation(s)
- Karin Naess
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
| | - Helene Bruhn
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Henrik Stranneheim
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Christoph Freyer
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Rolf Wibom
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Arnaud Mourier
- CNRS UMR 5095, Bordeaux Cedex, France; University of Bordeaux, EPST, IBGC UMR 5095, Bordeaux Cedex, France
| | - Martin Engvall
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Inger Nennesmo
- Clinical Pathology, Karolinska University Hospital, Department of Laboratory Medicine, Stockholm, Sweden
| | - Nicole Lesko
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wredenberg
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wedell
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Ulrika von Döbeln
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
15
|
Wu J, Lu G. Multiple functions of TBCK protein in neurodevelopment disorders and tumors. Oncol Lett 2021; 21:17. [PMID: 33240423 PMCID: PMC7681195 DOI: 10.3892/ol.2020.12278] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 10/06/2020] [Indexed: 12/12/2022] Open
Abstract
TBC1 domain containing kinase (TBCK) protein is composed of three conserved domains, including N-terminal Serine/Threonine kinase domain, central TBC domain and C-terminal rhodanese homology domain (RHOD). A total of 9 different transcripts (classified as long and short TBCK) generated by alternative splicing have been reported in different cell lines. Exogenous expression of long TBCK has been identified to function as a suppressor of cell growth in certain cell types. On the contrary, TBCK has also been reported to serve a tumor-promoting role in other cell lines, indicating that TBCK might function differentially, depending on the context in different cellular environments. Furthermore, deleterious homozygous or compound heterozygous mutations identified by whole-exome sequencing in the TBCK gene could ablate the function of TBCK, further impacting the mTOR signaling pathway and leading to neurogenetic disorders, such as hypotonia, global developmental delay, facial dysmorphic features and brain abnormalities. However, as a poorly explored protein, there are a lot of studies associated with the functions of TBCK that need to be performed in the future. The present review summarizes data regarding the structural features and potential roles of TBCK in developmental and neurological diseases and tumorigenesis. Future prospects of TBCK research lie in revealing numerous biological functions of TBCK.
Collapse
Affiliation(s)
- Jin Wu
- Center for Personalized Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA
| | - Guanting Lu
- Department of Pathology, People's Hospital of Deyang City, Deyang, Sichuan 618000, P.R. China
| |
Collapse
|
16
|
Harms FL, Parthasarathy P, Zorndt D, Alawi M, Fuchs S, Halliday BJ, McKeown C, Sampaio H, Radhakrishnan N, Radhakrishnan SK, Gorce M, Navet B, Ziegler A, Sachdev R, Robertson SP, Nampoothiri S, Kutsche K. Biallelic loss-of-function variants in TBC1D2B cause a neurodevelopmental disorder with seizures and gingival overgrowth. Hum Mutat 2020; 41:1645-1661. [PMID: 32623794 DOI: 10.1002/humu.24071] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/08/2020] [Accepted: 06/30/2020] [Indexed: 12/15/2022]
Abstract
The family of Tre2-Bub2-Cdc16 (TBC)-domain containing GTPase activating proteins (RABGAPs) is not only known as key regulatorof RAB GTPase activity but also has GAP-independent functions. Rab GTPases are implicated in membrane trafficking pathways, such as vesicular trafficking. We report biallelic loss-of-function variants in TBC1D2B, encoding a member of the TBC/RABGAP family with yet unknown function, as the underlying cause of cognitive impairment, seizures, and/or gingival overgrowth in three individuals from unrelated families. TBC1D2B messenger RNA amount was drastically reduced, and the protein was absent in fibroblasts of two patients. In immunofluorescence analysis, ectopically expressed TBC1D2B colocalized with vesicles positive for RAB5, a small GTPase orchestrating early endocytic vesicle trafficking. In two independent TBC1D2B CRISPR/Cas9 knockout HeLa cell lines that serve as cellular model of TBC1D2B deficiency, epidermal growth factor internalization was significantly reduced compared with the parental HeLa cell line suggesting a role of TBC1D2B in early endocytosis. Serum deprivation of TBC1D2B-deficient HeLa cell lines caused a decrease in cell viability and an increase in apoptosis. Our data reveal that loss of TBC1D2B causes a neurodevelopmental disorder with gingival overgrowth, possibly by deficits in vesicle trafficking and/or cell survival.
Collapse
Affiliation(s)
- Frederike L Harms
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Padmini Parthasarathy
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Dennis Zorndt
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Malik Alawi
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sigrid Fuchs
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Benjamin J Halliday
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Colina McKeown
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Hugo Sampaio
- Department of Women and Children's Health, University of New South Wales, Randwick Campus, Randwick, NSW, Australia.,Sydney Children's Hospital, Randwick, NSW, Australia
| | - Natasha Radhakrishnan
- Department of Ophthalmology, Amrita Institute of Medical Sciences and Research Centre, Cochin, Kerala, India
| | - Suresh K Radhakrishnan
- Department of Neurology, Amrita Institute of Medical Sciences and Research Centre, Cochin, Kerala, India
| | - Magali Gorce
- Department of Metabolic Disease, Children University Hospital, Toulouse, France
| | - Benjamin Navet
- Department of Biochemistry and Genetics, University Hospital of Angers, Angers, France.,MitoLab, Institut MitoVasc, UMR CNRS6015, INSERM U1083, Angers, France
| | - Alban Ziegler
- Department of Biochemistry and Genetics, University Hospital of Angers, Angers, France.,MitoLab, Institut MitoVasc, UMR CNRS6015, INSERM U1083, Angers, France
| | - Rani Sachdev
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Stephen P Robertson
- Department of Women's and Children's Health, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Sheela Nampoothiri
- Department of Pediatric Genetics, Amrita Institute of Medical Sciences and Research Centre, Cochin, Kerala, India
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
17
|
Saredi S, Cauley ES, Ruggieri A, Spivey TM, Ardissone A, Mora M, Moroni I, Manzini MC. Myopathic changes associated with psychomotor delay and seizures caused by a novel homozygous mutation in TBCK. Muscle Nerve 2020; 62:266-271. [PMID: 32363625 DOI: 10.1002/mus.26907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 04/16/2020] [Accepted: 04/25/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Biallelic mutations in TBC1-domain containing kinase (TBCK) lead to hypotonia, global developmental delay with severe cognitive and motor deficits, and variable presentation of dysmorphic facial features and brain malformations. It remains unclear whether hypotonia in these individuals is purely neurogenic, or also caused by progressive muscle disease. METHODS Whole exome sequencing was performed on a family diagnosed with nonspecific myopathic changes by means of histological analysis and immunohistochemistry of muscle biopsy samples. RESULTS A novel homozygous truncation in TBCK was found in two sisters diagnosed with muscle disease and severe psychomotor delay. TBCK was completely absent in these patients. CONCLUSIONS Our findings identify a novel early truncating variant in TBCK associated with a severe presentation and add muscle disease to the variability of phenotypes associated with TBCK mutations. Inconsistent genotype/phenotype correlation could be ascribed to the multiple roles of TBCK in intracellular signaling and endolysosomal function in different tissues.
Collapse
Affiliation(s)
- Simona Saredi
- Neuromuscular Disease and Immunology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Edmund S Cauley
- Institute for Neuroscience and Department of Pharmacology and Physiology, George Washington University, Washington, DC
| | - Alessandra Ruggieri
- Neuromuscular Disease and Immunology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy.,Biology and Genetic Division, Molecular and Translational Medicine Department, University of Brescia, Brescia, Italy
| | - Tyler M Spivey
- Institute for Neuroscience and Department of Pharmacology and Physiology, George Washington University, Washington, DC
| | - Anna Ardissone
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Marina Mora
- Neuromuscular Disease and Immunology Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Istituto Neurologico Carlo Besta, Milan, Italy
| | - Isabella Moroni
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - M Chiara Manzini
- Institute for Neuroscience and Department of Pharmacology and Physiology, George Washington University, Washington, DC.,Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey
| |
Collapse
|
18
|
Fassio A, Falace A, Esposito A, Aprile D, Guerrini R, Benfenati F. Emerging Role of the Autophagy/Lysosomal Degradative Pathway in Neurodevelopmental Disorders With Epilepsy. Front Cell Neurosci 2020; 14:39. [PMID: 32231521 PMCID: PMC7082311 DOI: 10.3389/fncel.2020.00039] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/10/2020] [Indexed: 01/08/2023] Open
Abstract
Autophagy is a highly conserved degradative process that conveys dysfunctional proteins, lipids, and organelles to lysosomes for degradation. The post-mitotic nature, complex and highly polarized morphology, and high degree of specialization of neurons make an efficient autophagy essential for their homeostasis and survival. Dysfunctional autophagy occurs in aging and neurodegenerative diseases, and autophagy at synaptic sites seems to play a crucial role in neurodegeneration. Moreover, a role of autophagy is emerging for neural development, synaptogenesis, and the establishment of a correct connectivity. Thus, it is not surprising that defective autophagy has been demonstrated in a spectrum of neurodevelopmental disorders, often associated with early-onset epilepsy. Here, we discuss the multiple roles of autophagy in neurons and the recent experimental evidence linking neurodevelopmental disorders with epilepsy to genes coding for autophagic/lysosomal system-related proteins and envisage possible pathophysiological mechanisms ranging from synaptic dysfunction to neuronal death.
Collapse
Affiliation(s)
- Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Antonio Falace
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Alessandro Esposito
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Davide Aprile
- Department of Experimental Medicine, University of Genoa, Genoa, Italy.,Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy.,IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Fabio Benfenati
- IRCCS Ospedale Policlinico San Martino, Genoa, Italy.,Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy
| |
Collapse
|
19
|
Teinert J, Behne R, Wimmer M, Ebrahimi-Fakhari D. Novel insights into the clinical and molecular spectrum of congenital disorders of autophagy. J Inherit Metab Dis 2020; 43:51-62. [PMID: 30854657 DOI: 10.1002/jimd.12084] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/07/2019] [Indexed: 12/24/2022]
Abstract
Autophagy is a fundamental and conserved catabolic pathway that mediates the degradation of macromolecules and organelles in lysosomes. Autophagy is particularly important to postmitotic and metabolically active cells such as neurons. The complex architecture of neurons and their long axons pose additional challenges for efficient recycling of cargo. Not surprisingly autophagy is required for normal central nervous system development and function. Several single-gene disorders of the autophagy pathway have been discovered in recent years giving rise to a novel group of inborn errors of metabolism referred to as congenital disorders of autophagy. While these disorders are heterogeneous, they share several clinical and molecular characteristics including a prominent and progressive involvement of the central nervous system leading to brain malformations, developmental delay, intellectual disability, epilepsy, movement disorders, and cognitive decline. On brain magnetic resonance imaging a predominant involvement of the corpus callosum, the corticospinal tracts and the cerebellum are noted. A storage disease phenotype is present in some diseases, underscoring both clinical and molecular overlaps to lysosomal storage diseases. This review provides an update on the clinical, imaging, and genetic spectrum of congenital disorders of autophagy and highlights the importance of this pathway for neurometabolism and childhood-onset neurological diseases.
Collapse
Affiliation(s)
- Julian Teinert
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Robert Behne
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Miriam Wimmer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
20
|
Hancarova M, Babikyan D, Bendova S, Midyan S, Prchalova D, Shahsuvaryan G, Stranecky V, Sarkisian T, Sedlacek Z. A novel variant of C12orf4 in a consanguineous Armenian family confirms the etiology of autosomal recessive intellectual disability type 66 with delineation of the phenotype. Mol Genet Genomic Med 2019; 7:e865. [PMID: 31334606 PMCID: PMC6732288 DOI: 10.1002/mgg3.865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/01/2019] [Accepted: 07/05/2019] [Indexed: 01/07/2023] Open
Abstract
Background Intellectual disability (ID) is a feature of many rare diseases caused by thousands of genes. This genetic heterogeneity implies that pathogenic variants in a specific gene are found only in a small number of patients, and difficulties arise in the definition of prevailing genotype and characteristic phenotype associated with that gene. One of such very rare disorders is autosomal recessive ID type 66 (OMIM #618221) caused by defects in C12orf4. Up to now, six families have been reported with mostly truncating variants. The spectrum of the clinical phenotype was not emphasized in previous reports, and detailed phenotype was not always available from previous patients, especially from large cohort studies. Methods Exome sequencing was performed in a consanguineous Armenian family with two affected adult brothers. Results The patients carry a novel homozygous nonsense C12orf4 variant. The integration of previous data and phenotyping of the brothers indicate that the clinical picture of C12orf4 defects involves hypotonia in infancy, rather severe ID, speech impairment, and behavioral problems such as aggressiveness, unstable mood, and autistic features. Several other symptoms are more variable and less consistent. Conclusion This rather nonsyndromic and nonspecific clinical picture implies that additional patients with C12orf4 defects will likely continue to be identified using the “genotype‐first” approach, rather than based on clinical assessment. The phenotype needs further delineation in future reports.
Collapse
Affiliation(s)
- Miroslava Hancarova
- Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Davit Babikyan
- Department of Medical Genetics, Yerevan State Medical University after Mkhitar Heratsi, and Center of Medical Genetics and Primary Health Care, Yerevan, Armenia
| | - Sarka Bendova
- Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Susanna Midyan
- Department of Medical Genetics, Yerevan State Medical University after Mkhitar Heratsi, and Center of Medical Genetics and Primary Health Care, Yerevan, Armenia
| | - Darina Prchalova
- Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| | - Gohar Shahsuvaryan
- Department of Medical Genetics, Yerevan State Medical University after Mkhitar Heratsi, and Center of Medical Genetics and Primary Health Care, Yerevan, Armenia
| | - Viktor Stranecky
- Department of Pediatrics and Adolescent Medicine, Charles University 1st Faculty of Medicine and General University Hospital, Prague, Czech Republic
| | - Tamara Sarkisian
- Department of Medical Genetics, Yerevan State Medical University after Mkhitar Heratsi, and Center of Medical Genetics and Primary Health Care, Yerevan, Armenia
| | - Zdenek Sedlacek
- Department of Biology and Medical Genetics, Charles University 2nd Faculty of Medicine and University Hospital Motol, Prague, Czech Republic
| |
Collapse
|
21
|
Gillingham AK, Bertram J, Begum F, Munro S. In vivo identification of GTPase interactors by mitochondrial relocalization and proximity biotinylation. eLife 2019; 8:45916. [PMID: 31294692 PMCID: PMC6639074 DOI: 10.7554/elife.45916] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 07/10/2019] [Indexed: 12/11/2022] Open
Abstract
The GTPases of the Ras superfamily regulate cell growth, membrane traffic and the cytoskeleton, and a wide range of diseases are caused by mutations in particular members. They function as switchable landmarks with the active GTP-bound form recruiting to the membrane a specific set of effector proteins. The GTPases are precisely controlled by regulators that promote acquisition of GTP (GEFs) or its hydrolysis to GDP (GAPs). We report here MitoID, a method for identifying effectors and regulators by performing in vivo proximity biotinylation with mitochondrially-localized forms of the GTPases. Applying this to 11 human Rab GTPases identified many known effectors and GAPs, as well as putative novel effectors, with examples of the latter validated for Rab2, Rab5, Rab9 and Rab11. MitoID can also efficiently identify effectors and GAPs of Rho and Ras family GTPases such as Cdc42, RhoA, Rheb, and N-Ras, and can identify GEFs by use of GDP-bound forms.
Collapse
Affiliation(s)
| | - Jessie Bertram
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Farida Begum
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| |
Collapse
|
22
|
TBCK Encephaloneuropathy With Abnormal Lysosomal Storage: Use of a Structural Variant Bioinformatics Pipeline on Whole-Genome Sequencing Data Unravels a 20-Year-Old Clinical Mystery. Pediatr Neurol 2019; 96:74-75. [PMID: 30898414 DOI: 10.1016/j.pediatrneurol.2019.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 01/31/2019] [Accepted: 02/02/2019] [Indexed: 11/23/2022]
|
23
|
Qu L, Pan C, He SM, Lang B, Gao GD, Wang XL, Wang Y. The Ras Superfamily of Small GTPases in Non-neoplastic Cerebral Diseases. Front Mol Neurosci 2019; 12:121. [PMID: 31213978 PMCID: PMC6555388 DOI: 10.3389/fnmol.2019.00121] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/25/2019] [Indexed: 12/22/2022] Open
Abstract
The small GTPases from the Ras superfamily play crucial roles in basic cellular processes during practically the entire process of neurodevelopment, including neurogenesis, differentiation, gene expression, membrane and protein traffic, vesicular trafficking, and synaptic plasticity. Small GTPases are key signal transducing enzymes that link extracellular cues to the neuronal responses required for the construction of neuronal networks, as well as for synaptic function and plasticity. Different subfamilies of small GTPases have been linked to a number of non-neoplastic cerebral diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), intellectual disability, epilepsy, drug addiction, Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS) and a large number of idiopathic cerebral diseases. Here, we attempted to make a clearer illustration of the relationship between Ras superfamily GTPases and non-neoplastic cerebral diseases, as well as their roles in the neural system. In future studies, potential treatments for non-neoplastic cerebral diseases which are based on small GTPase related signaling pathways should be explored further. In this paper, we review all the available literature in support of this possibility.
Collapse
Affiliation(s)
- Liang Qu
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Chao Pan
- Beijing Institute of Biotechnology, Beijing, China
| | - Shi-Ming He
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China.,Department of Neurosurgery, Xi'an International Medical Center, Xi'an, China
| | - Bing Lang
- The School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom.,Department of Psychiatry, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Guo-Dong Gao
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Xue-Lian Wang
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| | - Yuan Wang
- Department of Neurosurgery, Tangdu Hospital, Air Force Military Medical University, Xi'an, China
| |
Collapse
|
24
|
Ortiz-González XR, Tintos-Hernández JA, Keller K, Li X, Foley AR, Bharucha-Goebel DX, Kessler SK, Yum SW, Crino PB, He M, Wallace DC, Bönnemann CG. Homozygous boricua TBCK mutation causes neurodegeneration and aberrant autophagy. Ann Neurol 2019; 83:153-165. [PMID: 29283439 DOI: 10.1002/ana.25130] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 12/26/2017] [Accepted: 12/26/2017] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Autosomal-recessive mutations in TBCK cause intellectual disability of variable severity. Although the physiological function of TBCK remains unclear, loss-of-function mutations are associated with inhibition of mechanistic target of rapamycin complex 1 (mTORC1) signaling. Given that mTORC1 signaling is known to regulate autophagy, we hypothesized that TBCK-encephalopathy patients with a neurodegenerative course have defects in autophagic-lysosomal dysfunction. METHODS Children (n = 8) of Puerto Rican (Boricua) descent affected with homozygous TBCK p.R126X mutations underwent extensive neurological phenotyping and neurophysiological studies. We quantified autophagosome content in TBCK-/- patient-derived fibroblasts by immunostaining and assayed autophagic markers by western assay. Free sialylated oligosaccharide profiles were assayed in patient's urine and fibroblasts. RESULTS The neurological phenotype of children with TBCK p.R126X mutations, which we call TBCK-encephaloneuronopathy (TBCKE), include congenital hypotonia, progressive motor neuronopathy, leukoencephalopathy, and epilepsy. Systemic features include coarse facies, dyslipidemia, and osteoporosis. TBCK-/- fibroblasts in vitro exhibit increased numbers of LC3+ autophagosomes and increased autophagic flux by immunoblots. Free oligosaccharide profiles in fibroblasts and urine of TBCKE patients differ from control fibroblasts and are ameliorated by treatment with the mTORC1 activator leucine. INTERPRETATION TBCKE is a clinically distinguishable syndrome with progressive central and peripheral nervous system dysfunction, consistently observed in patients with the p.R126X mutation. We provide evidence that inappropriate autophagy in the absence of cellular stressors may play a role in this disorder, and that mTORC1 activation may ameliorate the autophagic-lysosomal system dysfunction. Free oligosaccharide profiles could serve as a novel biomarker for this disorder as well as a tool to evaluate potential therapeutic interventions. Ann Neurol 2018;83:153-165.
Collapse
Affiliation(s)
- Xilma R Ortiz-González
- Department of Pediatrics, Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA
| | - Jesus A Tintos-Hernández
- Department of Pediatrics, Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA.,Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Kierstin Keller
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Xueli Li
- Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Diana X Bharucha-Goebel
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD.,Division of Neurology, Children's National Health System, Washington, DC
| | - Sudha K Kessler
- Department of Pediatrics, Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Sabrina W Yum
- Department of Pediatrics, Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD
| | - Miao He
- Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Douglas C Wallace
- Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA.,Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| |
Collapse
|
25
|
Beck-Wödl S, Harzer K, Sturm M, Buchert R, Rieß O, Mennel HD, Latta E, Pagenstecher A, Keber U. Homozygous TBC1 domain-containing kinase (TBCK) mutation causes a novel lysosomal storage disease - a new type of neuronal ceroid lipofuscinosis (CLN15)? Acta Neuropathol Commun 2018; 6:145. [PMID: 30591081 PMCID: PMC6307319 DOI: 10.1186/s40478-018-0646-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 12/03/2018] [Indexed: 02/07/2023] Open
Abstract
Homozygous mutation of TBC1 domain-containing kinase (TBCK) is the cause of a very recently defined severe childhood disorder, which is characterized by severe hypotonia, global developmental delay, intellectual disability, epilepsy, characteristic facies and premature death. The link between TBCK loss of function and symptoms in patients with TBCK deficiency disorder (TBCK-DD) remains elusive. Here we demonstrate for the first time the histopathological characteristics of TBCK deficiency consisting of 1) a widespread and massive accumulation of lipofuscin storage material in neurons of the central nervous system without notable neuronal degeneration, 2) storage deposits in few astrocytes, 3) carbohydrate-rich deposits in brain, spleen and liver and 4) vacuolated lymphocytes. Biochemical examinations ruled out more than 20 known lysosomal storage diseases. These investigations strikingly uncover TBCK-DD as a novel type of lysosomal storage disease which is characterized by different storage products rather than one specific type of accumulated material. Due to the clear predominance of intraneuronal lipofuscin storage material and the characteristic clinical presentation we propose to classify this disease as a new subtype of neuronal ceroid lipofuscinosis (CLN15). Our results and previous reports suggest an autophagosomal-lysosomal dysfunction caused by enhanced mTORC1-mediated autophagosome formation and reduced Rab-mediated autophagosome-lysosome fusion, thus disclosing potential novel targets for therapeutic approaches in TBCK-DD.
Collapse
|
26
|
Calhoun JD, Carvill GL. Unravelling the genetic architecture of autosomal recessive epilepsy in the genomic era. J Neurogenet 2018; 32:295-312. [PMID: 30247086 DOI: 10.1080/01677063.2018.1513509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The technological advancement of next-generation sequencing has greatly accelerated the pace of variant discovery in epilepsy. Despite an initial focus on autosomal dominant epilepsy due to the tractable nature of variant discovery with trios under a de novo model, more and more variants are being reported in families with epilepsies consistent with autosomal recessive (AR) inheritance. In this review, we touch on the classical AR epilepsy variants such as the inborn errors of metabolism and malformations of cortical development. However, we also highlight recently reported genes that are being identified by next-generation sequencing approaches and online 'matchmaking' platforms. Syndromes mainly characterized by seizures and complex neurodevelopmental disorders comorbid with epilepsy are discussed as an example of the wide phenotypic spectrum associated with the AR epilepsies. We conclude with a foray into the future, from the application of whole-genome sequencing to identify elusive epilepsy variants, to the promise of precision medicine initiatives to provide novel targeted therapeutics specific to the individual based on their clinical genetic testing.
Collapse
Affiliation(s)
- Jeffrey D Calhoun
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
| | - Gemma L Carvill
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
| |
Collapse
|
27
|
Further delineation of TBCK - Infantile hypotonia with psychomotor retardation and characteristic facies type 3. Eur J Med Genet 2018; 62:273-277. [PMID: 30103036 DOI: 10.1016/j.ejmg.2018.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 07/23/2018] [Accepted: 08/09/2018] [Indexed: 01/19/2023]
Abstract
Deleterious homozygous or compound heterozygous mutations in the TBCK (TBC1-domain-containing kinase) gene (implicated in the MTOR pathway) produce profound hypotonia, global developmental delay, facial dysmorphic features, and brain abnormalities. The disorder has been named "infantile hypotonia with psychomotor retardation and characteristic facies-3" (IHPRF3). Here we present two sisters with a novel mutation in TBCK (NM_001163435.2: c.753dup; p.(Lys252*)) who have this ultrarare disorder. We have reviewed the literature on the 33 previously reported cases to provide a characterization of this emerging phenotype. Pathogenic mutations in TBCK have a predominant involvement of the Central Nervous System with a progressive pattern, leading to the conclusion where pathogenic mutations of the said gene lead to a progressive neurodegenerative disease. This report adds novel mutation and features to this complex phenotype. Further investigation is required to understand the pathogenesis of TBCK.
Collapse
|
28
|
Homozygous Mutations in TBC1D23 Lead to a Non-degenerative Form of Pontocerebellar Hypoplasia. Am J Hum Genet 2017; 101:441-450. [PMID: 28823706 DOI: 10.1016/j.ajhg.2017.07.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/17/2017] [Indexed: 01/12/2023] Open
Abstract
Pontocerebellar hypoplasia (PCH) represents a group of recessive developmental disorders characterized by impaired growth of the pons and cerebellum, which frequently follows a degenerative course. Currently, there are 10 partially overlapping clinical subtypes and 13 genes known mutated in PCH. Here, we report biallelic TBC1D23 mutations in six individuals from four unrelated families manifesting a non-degenerative form of PCH. In addition to reduced volume of pons and cerebellum, affected individuals had microcephaly, psychomotor delay, and ataxia. In zebrafish, tbc1d23 morphants replicated the human phenotype showing hindbrain volume loss. TBC1D23 localized at the trans-Golgi and was regulated by the small GTPases Arl1 and Arl8, suggesting a role in trans-Golgi membrane trafficking. Altogether, this study provides a causative link between TBC1D23 mutations and PCH and suggests a less severe clinical course than other PCH subtypes.
Collapse
|
29
|
Wangler MF, Yamamoto S, Chao HT, Posey JE, Westerfield M, Postlethwait J, Hieter P, Boycott KM, Campeau PM, Bellen HJ. Model Organisms Facilitate Rare Disease Diagnosis and Therapeutic Research. Genetics 2017; 207:9-27. [PMID: 28874452 PMCID: PMC5586389 DOI: 10.1534/genetics.117.203067] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 07/06/2017] [Indexed: 12/29/2022] Open
Abstract
Efforts to identify the genetic underpinnings of rare undiagnosed diseases increasingly involve the use of next-generation sequencing and comparative genomic hybridization methods. These efforts are limited by a lack of knowledge regarding gene function, and an inability to predict the impact of genetic variation on the encoded protein function. Diagnostic challenges posed by undiagnosed diseases have solutions in model organism research, which provides a wealth of detailed biological information. Model organism geneticists are by necessity experts in particular genes, gene families, specific organs, and biological functions. Here, we review the current state of research into undiagnosed diseases, highlighting large efforts in North America and internationally, including the Undiagnosed Diseases Network (UDN) (Supplemental Material, File S1) and UDN International (UDNI), the Centers for Mendelian Genomics (CMG), and the Canadian Rare Diseases Models and Mechanisms Network (RDMM). We discuss how merging human genetics with model organism research guides experimental studies to solve these medical mysteries, gain new insights into disease pathogenesis, and uncover new therapeutic strategies.
Collapse
Affiliation(s)
- Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, Texas 77030
- Department of Pediatrics, Baylor College of Medicine (BCM), Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, Texas 77030
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, Texas 77030
- Department of Neuroscience, Baylor College of Medicine (BCM), Houston, Texas 77030
| | - Hsiao-Tuan Chao
- Department of Pediatrics, Baylor College of Medicine (BCM), Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
- Department of Pediatrics, Section of Child Neurology, Baylor College of Medicine (BCM), Houston, Texas 77030
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, Texas 77030
| | - Monte Westerfield
- Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403
| | - John Postlethwait
- Institute of Neuroscience, University of Oregon, Eugene, Oregon 97403
| | - Philip Hieter
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4C, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ontario K1H 8L1, Canada
| | - Philippe M Campeau
- Department of Pediatrics, University of Montreal, Quebec H3T 1C5, Canada
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, Texas 77030
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas 77030
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, Texas 77030
- Department of Neuroscience, Baylor College of Medicine (BCM), Houston, Texas 77030
- Howard Hughes Medical Institute, Baylor College of Medicine (BCM), Houston, Texas 77030
| |
Collapse
|
30
|
Mutations in TRAPPC12 Manifest in Progressive Childhood Encephalopathy and Golgi Dysfunction. Am J Hum Genet 2017; 101:291-299. [PMID: 28777934 DOI: 10.1016/j.ajhg.2017.07.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/06/2017] [Indexed: 12/23/2022] Open
Abstract
Progressive childhood encephalopathy is an etiologically heterogeneous condition characterized by progressive central nervous system dysfunction in association with a broad range of morbidity and mortality. The causes of encephalopathy can be either non-genetic or genetic. Identifying the genetic causes and dissecting the underlying mechanisms are critical to understanding brain development and improving treatments. Here, we report that variants in TRAPPC12 result in progressive childhood encephalopathy. Three individuals from two unrelated families have either a homozygous deleterious variant (c.145delG [p.Glu49Argfs∗14]) or compound-heterozygous variants (c.360dupC [p.Glu121Argfs∗7] and c.1880C>T [p. Ala627Val]). The clinical phenotypes of the three individuals are strikingly similar: severe disability, microcephaly, hearing loss, spasticity, and characteristic brain imaging findings. Fibroblasts derived from all three individuals showed a fragmented Golgi that could be rescued by expression of wild-type TRAPPC12. Protein transport from the endoplasmic reticulum to and through the Golgi was delayed. TRAPPC12 is a member of the TRAPP protein complex, which functions in membrane trafficking. Variants in several other genes encoding members of the TRAPP complex have been associated with overlapping clinical presentations, indicating shared and distinct functions for each complex member. Detailed understanding of the TRAPP-opathies will illuminate the role of membrane protein transport in human disease.
Collapse
|
31
|
Mandel H, Khayat M, Chervinsky E, Elpeleg O, Shalev S. TBCK-related intellectual disability syndrome: Case study of two patients. Am J Med Genet A 2016; 173:491-494. [PMID: 27748029 DOI: 10.1002/ajmg.a.38019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/25/2016] [Indexed: 11/09/2022]
Abstract
There is a significant level of genetic heterogeneity underlying the phenotype of nonspecific hypotonia with severe intellectual disability. Exome sequencing has proven to be a powerful tool for identifying the underlying molecular basis of such nonspecific, abnormal neurological phenotypes. Mutations in the TBCK gene have been reported associated with very poor, if any, psychomotor development, poor speech, and inability to walk independently. We describe the long-term phenotypic evolution of a severe nonspecific neurodevelopmental disorder in two siblings born to an Arab-Moslem family living in northern Israel. Exome sequencing led to identification of a novel homozygous mutation: c.1854delT in the TBCK gene. Abnormal elevated β-HCG was found in the maternal serum during the two pregnancies, a finding that has not been reported before. These individuals present with severe intellectual disability, no speech, hypotonia, convulsions, and lack of any independent daily skills. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Hanna Mandel
- Rambam Health Care Campus, Metabolic Unit, Rappaport School of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Morad Khayat
- Genetics Institute, Ha'emek Medical Center, Afula, Israel
| | | | - Orly Elpeleg
- The Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Stavit Shalev
- Genetics Institute, Ha'emek Medical Center, Afula, Israel.,Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| |
Collapse
|
32
|
Flex E, Niceta M, Cecchetti S, Thiffault I, Au MG, Capuano A, Piermarini E, Ivanova AA, Francis JW, Chillemi G, Chandramouli B, Carpentieri G, Haaxma CA, Ciolfi A, Pizzi S, Douglas GV, Levine K, Sferra A, Dentici ML, Pfundt RR, Le Pichon JB, Farrow E, Baas F, Piemonte F, Dallapiccola B, Graham JM, Saunders CJ, Bertini E, Kahn RA, Koolen DA, Tartaglia M. Biallelic Mutations in TBCD, Encoding the Tubulin Folding Cofactor D, Perturb Microtubule Dynamics and Cause Early-Onset Encephalopathy. Am J Hum Genet 2016; 99:962-973. [PMID: 27666370 DOI: 10.1016/j.ajhg.2016.08.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/09/2016] [Indexed: 12/13/2022] Open
Abstract
Microtubules are dynamic cytoskeletal elements coordinating and supporting a variety of neuronal processes, including cell division, migration, polarity, intracellular trafficking, and signal transduction. Mutations in genes encoding tubulins and microtubule-associated proteins are known to cause neurodevelopmental and neurodegenerative disorders. Growing evidence suggests that altered microtubule dynamics may also underlie or contribute to neurodevelopmental disorders and neurodegeneration. We report that biallelic mutations in TBCD, encoding one of the five co-chaperones required for assembly and disassembly of the αβ-tubulin heterodimer, the structural unit of microtubules, cause a disease with neurodevelopmental and neurodegenerative features characterized by early-onset cortical atrophy, secondary hypomyelination, microcephaly, thin corpus callosum, developmental delay, intellectual disability, seizures, optic atrophy, and spastic quadriplegia. Molecular dynamics simulations predicted long-range and/or local structural perturbations associated with the disease-causing mutations. Biochemical analyses documented variably reduced levels of TBCD, indicating relative instability of mutant proteins, and defective β-tubulin binding in a subset of the tested mutants. Reduced or defective TBCD function resulted in decreased soluble α/β-tubulin levels and accelerated microtubule polymerization in fibroblasts from affected subjects, demonstrating an overall shift toward a more rapidly growing and stable microtubule population. These cells displayed an aberrant mitotic spindle with disorganized, tangle-shaped microtubules and reduced aster formation, which however did not alter appreciably the rate of cell proliferation. Our findings establish that defective TBCD function underlies a recognizable encephalopathy and drives accelerated microtubule polymerization and enhanced microtubule stability, underscoring an additional cause of altered microtubule dynamics with impact on neuronal function and survival in the developing brain.
Collapse
|