1
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Lolicato F, Nickel W, Haucke V, Ebner M. Phosphoinositide switches in cell physiology - From molecular mechanisms to disease. J Biol Chem 2024; 300:105757. [PMID: 38364889 PMCID: PMC10944118 DOI: 10.1016/j.jbc.2024.105757] [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: 11/28/2023] [Revised: 02/02/2024] [Accepted: 02/08/2024] [Indexed: 02/18/2024] Open
Abstract
Phosphoinositides are amphipathic lipid molecules derived from phosphatidylinositol that represent low abundance components of biological membranes. Rather than serving as mere structural elements of lipid bilayers, they represent molecular switches for a broad range of biological processes, including cell signaling, membrane dynamics and remodeling, and many other functions. Here, we focus on the molecular mechanisms that turn phosphoinositides into molecular switches and how the dysregulation of these processes can lead to disease.
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Affiliation(s)
- Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg, Germany; Department of Physics, University of Helsinki, Helsinki, Finland.
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany; Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Ebner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
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2
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Kušíková K, Šoltýsová A, Ficek A, Feichtinger RG, Mayr JA, Škopková M, Gašperíková D, Kolníková M, Ornig K, Kalev O, Weis S, Weis D. Prognostic Value of Genotype-Phenotype Correlations in X-Linked Myotubular Myopathy and the Use of the Face2Gene Application as an Effective Non-Invasive Diagnostic Tool. Genes (Basel) 2023; 14:2174. [PMID: 38136996 PMCID: PMC10742680 DOI: 10.3390/genes14122174] [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: 11/12/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND X-linked myotubular myopathy (XLMTM) is a rare congenital myopathy resulting from dysfunction of the protein myotubularin encoded by the MTM1 gene. XLMTM has a high neonatal and infantile mortality rate due to a severe myopathic phenotype and respiratory failure. However, in a minority of XLMTM cases, patients present with milder phenotypes and achieve ambulation and adulthood. Notable facial dysmorphia is also present. METHODS We investigated the genotype-phenotype correlations in newly diagnosed XLMTM patients in a patients' cohort (previously published data plus three novel variants, n = 414). Based on the facial gestalt difference between XLMTM patients and unaffected controls, we investigated the use of the Face2Gene application. RESULTS Significant associations between severe phenotype and truncating variants (p < 0.001), frameshift variants (p < 0.001), nonsense variants (p = 0.006), and in/del variants (p = 0.036) were present. Missense variants were significantly associated with the mild and moderate phenotype (p < 0.001). The Face2Gene application showed a significant difference between XLMTM patients and unaffected controls (p = 0.001). CONCLUSIONS Using genotype-phenotype correlations could predict the disease course in most XLMTM patients, but still with limitations. The Face2Gene application seems to be a practical, non-invasive diagnostic approach in XLMTM using the correct algorithm.
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Affiliation(s)
- Katarína Kušíková
- Department of Pediatric Neurology, Faculty of Medicine, Comenius University Bratislava and National Institute of Children’s Diseases, 83340 Bratislava, Slovakia; (K.K.)
| | - Andrea Šoltýsová
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215 Bratislava, Slovakia
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia
| | - Andrej Ficek
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215 Bratislava, Slovakia
| | - René G. Feichtinger
- University Children’s Hospital, SalzburgerLandeskliniken (SALK), Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (R.G.F.)
| | - Johannes A. Mayr
- University Children’s Hospital, SalzburgerLandeskliniken (SALK), Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (R.G.F.)
| | - Martina Škopková
- Department of Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Science, 84505 Bratislava, Slovakia
| | - Daniela Gašperíková
- Department of Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Science, 84505 Bratislava, Slovakia
| | - Miriam Kolníková
- Department of Pediatric Neurology, Faculty of Medicine, Comenius University Bratislava and National Institute of Children’s Diseases, 83340 Bratislava, Slovakia; (K.K.)
| | - Karoline Ornig
- Division of Neuropathology, Department of Pathology and Molecular Pathology, Neuromed Campus, Kepler University Hospital, Johannes Kepler University, 4020 Linz, Austria
| | - Ognian Kalev
- Division of Neuropathology, Department of Pathology and Molecular Pathology, Neuromed Campus, Kepler University Hospital, Johannes Kepler University, 4020 Linz, Austria
| | - Serge Weis
- Division of Neuropathology, Department of Pathology and Molecular Pathology, Neuromed Campus, Kepler University Hospital, Johannes Kepler University, 4020 Linz, Austria
| | - Denisa Weis
- Department of Medical Genetics, Kepler University Hospital Med Campus IV, Johannes Kepler University, 4020 Linz, Austria
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3
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Carvalho A, Costa C, Pinto M, Taipa R, Gonçalves A, Oliveira ME, Ferreira S, Ribeiro JA. X-Linked Myotubular Myopathy: A Novel Mutation Expanding the Genotypic Spectrum of a Phenotypically Heterogeneous Myopathy. J Pediatr Genet 2023; 12:258-262. [PMID: 37575650 PMCID: PMC10421687 DOI: 10.1055/s-0041-1728745] [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: 12/13/2020] [Accepted: 03/09/2021] [Indexed: 10/21/2022]
Abstract
X-linked myotubular myopathy (XLMTM), a centronuclear congenital myopathy secondary to pathogenic variants in the MTM1 gene encoding myotubularin, is typically recognized for its classic and severe phenotype which includes neonatal hypotonia, severe muscle weakness, long-term ventilator dependence, markedly delayed gross motor milestones with inability to independently ambulate, and a high neonatal and childhood mortality. However, milder congenital forms of the condition and other phenotypes are recognized. We describe a 6-year-old boy with a mild XLMTM phenotype with independent gait and no respiratory insufficiency even in the neonatal period. The child has a hemizygous novel splice site variant in the MTM1 gene (c.232-25A > T) whose pathogenicity was confirmed by cDNA studies (exon 5 skipping) and muscle biopsy findings. We also compared the phenotype of our patient with the few reported cases that presented a mild XLMTM phenotype and no respiratory distress at birth, and discussed the potential mechanisms underlying this phenotype such as the presence of residual expression of the normal myotubularin transcript.
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Affiliation(s)
- Andreia Carvalho
- Neurology Department, Centro Hospitalar de Vila Nova de Gaia–Espinho, Portugal
| | - Carmen Costa
- Pediatric Neurology Department, Centro de Desenvolvimento da Criança, Hospital Pediátrico de Coimbra - Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Miguel Pinto
- Neuropathology Unit, Hospital de Santo António - Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Ricardo Taipa
- Neuropathology Unit, Hospital de Santo António - Centro Hospitalar Universitário do Porto, Porto, Portugal
- Unit for Multidisciplinary Research In Biomedicine, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Ana Gonçalves
- Unit for Multidisciplinary Research In Biomedicine, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
- Molecular Genetics Unit, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Márcia E. Oliveira
- Unit for Multidisciplinary Research In Biomedicine, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
- Molecular Genetics Unit, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Sofia Ferreira
- Pulmonology Department, Hospital Pediátrico de Coimbra - Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Joana Afonso Ribeiro
- Pediatric Neurology Department, Centro de Desenvolvimento da Criança, Hospital Pediátrico de Coimbra - Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
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4
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Chausova P, Murtazina A, Stepanova A, Borovicov A, Kovalskaia V, Ryadninskaya N, Chukhrova A, Ryzhkova O, Poliakov A. X-Linked Myotubular Myopathy in a Female Patient with a Pathogenic Variant in the MTM1 Gene. Int J Mol Sci 2023; 24:ijms24098409. [PMID: 37176116 PMCID: PMC10179330 DOI: 10.3390/ijms24098409] [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: 03/15/2023] [Revised: 05/01/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
X-linked centronuclear myopathy is caused by pathogenic variants in the MTM1 gene, which encodes myotubularin, a phosphatidylinositol 3-phosphate (PI3P) phosphatase. This form of congenital myopathy predominantly affects males. This study presents a case of X-linked myotubular myopathy in a female carrier of a pathogenic c.1261-10A>G variant in the MTM1 gene.
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Affiliation(s)
- Polina Chausova
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Aysylu Murtazina
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Anna Stepanova
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Artem Borovicov
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Valeriia Kovalskaia
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Nina Ryadninskaya
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Alena Chukhrova
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Oxana Ryzhkova
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
| | - Aleksander Poliakov
- Research Centre for Medical Genetics, Moskvorechie Str. 1, 115522 Moscow, Russia
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5
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Bhattacharyya T, Ghosh A, Verma S, Raghu P, Sowdhamini R. Structural rationale to understand the effect of disease-associated mutations on Myotubularin. Curr Res Struct Biol 2023; 5:100100. [PMID: 37101954 PMCID: PMC10123148 DOI: 10.1016/j.crstbi.2023.100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 02/16/2023] [Accepted: 02/28/2023] [Indexed: 03/29/2023] Open
Abstract
Myotubularin or MTM1 is a lipid phosphatase that regulates vesicular trafficking in the cell. The MTM1 gene is mutated in a severe form of muscular disease, X-linked myotubular myopathy or XLMTM, affecting 1 in 50,000 newborn males worldwide. There have been several studies on the disease pathology of XLMTM, but the structural effects of missense mutations of MTM1 are underexplored due to the unavailability of a crystal structure. MTM1 consists of three domains-a lipid-binding N-terminal GRAM domain, the phosphatase domain and a coiled-coil domain which aids dimerisation of Myotubularin homologs. While most mutations reported to date map to the phosphatase domain of MTM1, the other two domains on the sequence are also frequently mutated in XLMTM. To understand the overall structural and functional effects of missense mutations on MTM1, we curated several missense mutations and performed in silico and in vitro studies. Apart from significantly impaired binding to substrate, abrogation of phosphatase activity was observed for a few mutants. Possible long-range effects of mutations from non-catalytic domains on phosphatase activity were observed as well. Coiled-coil domain mutants have been characterised here for the first time in XLMTM literature.
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6
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Woo H, Lee S, Han JY, Kim WJ, Kim MJ, Seong MW, Kim SY, Cho A, Lim BC, Kim KJ, Chae JH. Clinical Characteristics and Neurologic Outcomes of X-Linked Myotubular Myopathy. ANNALS OF CHILD NEUROLOGY 2022. [DOI: 10.26815/acn.2022.00171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Purpose: X-linked myotubular myopathy (XLMTM) is a rare condition of centronuclear myopathy caused by myotubularin 1 (MTM1) mutations. Patients with XLMTM show different neurodevelopmental outcomes after the neonatal period depending on age and acquired hypoxic damage. We aim to evaluate the clinical characteristics and neurodevelopmental outcomes of patients with XLMTM who were followed up at a single center. It is essential to understand the volume and conditions to prepare for being a candidate for new therapeutic strategies. Methods: Patients diagnosed with centronuclear myopathy by muscle pathology and MTM1 mutation analysis were included. We retrospectively investigated motor milestones, communication skills, and bulbar and respiratory function in the patients. The patients were categorized into two groups: with and without hypoxic insults (HI). Results: All 13 patients were severely affected by neonatal hypotonia and required respiratory support and a feeding tube during the neonatal period. The follow-up duration was 4.4 years (range, 0.3 to 8.9). In the non-HI group, developmental milestones were delayed but were slowly achieved. Some patients underwent training in oral feeding with thickened foods and weaning from ventilation. Patients with HI showed poor motor function catch-up and communication skills. Three deaths were associated with acute respiratory failure.Conclusion: Patients with XLMTM without HI can survive long-term with the slow achievement of motor milestones and bulbar and respiratory function. However, hypoxic brain damage following acute respiratory failure negatively influences their developmental potential or even lead to death. Therefore, parental education for proper respiratory management is necessary, especially for young children.
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7
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Gómez-Oca R, Cowling BS, Laporte J. Common Pathogenic Mechanisms in Centronuclear and Myotubular Myopathies and Latest Treatment Advances. Int J Mol Sci 2021; 22:11377. [PMID: 34768808 PMCID: PMC8583656 DOI: 10.3390/ijms222111377] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 10/18/2021] [Indexed: 01/18/2023] Open
Abstract
Centronuclear myopathies (CNM) are rare congenital disorders characterized by muscle weakness and structural defects including fiber hypotrophy and organelle mispositioning. The main CNM forms are caused by mutations in: the MTM1 gene encoding the phosphoinositide phosphatase myotubularin (myotubular myopathy), the DNM2 gene encoding the mechanoenzyme dynamin 2, the BIN1 gene encoding the membrane curvature sensing amphiphysin 2, and the RYR1 gene encoding the skeletal muscle calcium release channel/ryanodine receptor. MTM1, BIN1, and DNM2 proteins are involved in membrane remodeling and trafficking, while RyR1 directly regulates excitation-contraction coupling (ECC). Several CNM animal models have been generated or identified, which confirm shared pathological anomalies in T-tubule remodeling, ECC, organelle mispositioning, protein homeostasis, neuromuscular junction, and muscle regeneration. Dynamin 2 plays a crucial role in CNM physiopathology and has been validated as a common therapeutic target for three CNM forms. Indeed, the promising results in preclinical models set up the basis for ongoing clinical trials. Another two clinical trials to treat myotubular myopathy by MTM1 gene therapy or tamoxifen repurposing are also ongoing. Here, we review the contribution of the different CNM models to understanding physiopathology and therapy development with a focus on the commonly dysregulated pathways and current therapeutic targets.
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Affiliation(s)
- Raquel Gómez-Oca
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France;
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, 67400 Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, 67400 Illkirch, France
- Strasbourg University, 67081 Strasbourg, France
- Dynacure, 67400 Illkirch, France;
| | | | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France;
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, 67400 Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, 67400 Illkirch, France
- Strasbourg University, 67081 Strasbourg, France
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8
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Duong T, Harding G, Mannix S, Abel C, Phillips D, Alfano LN, Bönnemann CG, Lilien C, Lowes LP, Servais L, Warken-Madelung B, Nieto Bergman S, James ES, Noursalehi M, Prasad S, Rico S, Bilder DA. Use of the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) in X-Linked Myotubular Myopathy: Content Validity and Psychometric Performance. J Neuromuscul Dis 2021; 8:63-77. [PMID: 32925083 PMCID: PMC7902972 DOI: 10.3233/jnd-200479] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
X-linked myotubular myopathy (XLMTM) is a life-threatening, congenital myopathy characterized by extreme hypotonia, weakness, delayed motor milestones, and respiratory failure, often resulting in pediatric mortality. This study evaluated the content validity and psychometric performance of the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders as a measure of neuromuscular functioning in children with X-linked myotubular myopathy. This study was conducted in two phases. Phase I assessed the content validity of the measure for use in an XLMTM pediatric population through: literature review, clinical expert interviews, caregiver interviews, and a modified-Delphi panel among clinicians. Phase II assessed psychometric performance based on the INCEPTUS observational clinical study and the ASPIRO interventional gene therapy study, including tests of reliability (internal consistency, test-retest, and interrater), validity (construct and criterion), and responsiveness based on observational and interventional clinical trial data analyses. Data established construct validity and reliability of the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders among XLMTM patients before administration of resamirigene bilparvovec, and sensitivity to study drug administration as evidenced by the significant post-administration response in ASPIRO. Findings support the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders as an appropriate neuromuscular functioning assessment in a pediatric X-linked myotubular myopathy patient population.
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Affiliation(s)
| | | | | | | | | | | | | | - Charlotte Lilien
- MDUK Oxford Neuromuscular Centre, Oxford, United Kingdom.,Institut I-Motion, Institut de Myologie, Paris, France
| | | | - Laurent Servais
- MDUK Oxford Neuromuscular Centre, Oxford, United Kingdom.,Institut I-Motion, Institut de Myologie, Paris, France.,University Hospital Liège & University of La Citadelle, Liège, Belgium
| | | | | | - Emma S James
- Encoded Therapeutics, South San Francisco, CA, USA formerly at Audentes Therapeutics, an Astellas Company, San Francisco, CA, USA
| | | | - Suyash Prasad
- Suyash Prasad Consulting, LLC, San Francisco, CA, USA formerly at Audentes Therapeutics, an Astellas Company, San Francisco, CA, USA
| | - Salvador Rico
- Encoded Therapeutics, South San Francisco, CA, USA formerly at Audentes Therapeutics, an Astellas Company, San Francisco, CA, USA
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9
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Yarwood R, Hellicar J, Woodman PG, Lowe M. Membrane trafficking in health and disease. Dis Model Mech 2020; 13:13/4/dmm043448. [PMID: 32433026 PMCID: PMC7197876 DOI: 10.1242/dmm.043448] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Membrane trafficking pathways are essential for the viability and growth of cells, and play a major role in the interaction of cells with their environment. In this At a Glance article and accompanying poster, we outline the major cellular trafficking pathways and discuss how defects in the function of the molecular machinery that mediates this transport lead to various diseases in humans. We also briefly discuss possible therapeutic approaches that may be used in the future treatment of trafficking-based disorders. Summary: This At a Glance article and poster summarise the major intracellular membrane trafficking pathways and associated molecular machineries, and describe how defects in these give rise to disease in humans.
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Affiliation(s)
- Rebecca Yarwood
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - John Hellicar
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Philip G Woodman
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
| | - Martin Lowe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK
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10
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A mutation in MTM1 causes X-Linked myotubular myopathy in Boykin spaniels. Neuromuscul Disord 2020; 30:353-359. [PMID: 32417001 DOI: 10.1016/j.nmd.2020.02.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 02/18/2020] [Accepted: 02/28/2020] [Indexed: 12/30/2022]
Abstract
The purpose of this study was to report the findings of clinical and genetic evaluation of a 3-month old male Boykin spaniel (the proband) that presented with progressive weakness. The puppy underwent a physical and neurological examination, serum biochemistry and complete blood cell count, electrophysiological testing, muscle biopsy and whole genome sequencing. Clinical evaluation revealed generalized neuromuscular weakness with tetraparesis and difficulty holding the head up and a dropped jaw. There was diffuse spontaneous activity on electromyography, most severe in the cervical musculature. Nerve conduction studies were normal, the findings were interpreted as consistent with a myopathy. Skeletal muscle was grossly abnormal on biopsy and there were necklace fibers and abnormal triad structure localization on histopathology, consistent with myotubular myopathy. Whole genome sequencing revealed a premature stop codon in exon 13 of MTM1 (ChrX: 118,903,496 C > T, c.1467C>T, p.Arg512X). The puppy was humanely euthanized at 5 months of age. The puppy's dam was heterozygous for the variant, and 3 male puppies from a subsequent litter all of which died by 2 weeks of age were hemizygous for the variant. This naturally occurring mutation in Boykin spaniels causes a severe form of X-linked myotubular myopathy, comparable to the human counterpart.
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11
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Gayi E, Neff LA, Massana Muñoz X, Ismail HM, Sierra M, Mercier T, Décosterd LA, Laporte J, Cowling BS, Dorchies OM, Scapozza L. Tamoxifen prolongs survival and alleviates symptoms in mice with fatal X-linked myotubular myopathy. Nat Commun 2018; 9:4848. [PMID: 30451843 PMCID: PMC6243013 DOI: 10.1038/s41467-018-07058-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/12/2018] [Indexed: 11/08/2022] Open
Abstract
X-linked myotubular myopathy (XLMTM, also known as XLCNM) is a severe congenital muscular disorder due to mutations in the myotubularin gene, MTM1. It is characterized by generalized hypotonia, leading to neonatal death of most patients. No specific treatment exists. Here, we show that tamoxifen, a well-known drug used against breast cancer, rescues the phenotype of Mtm1-deficient mice. Tamoxifen increases lifespan several-fold while improving overall motor function and preventing disease progression including lower limb paralysis. Tamoxifen corrects functional, histological and molecular hallmarks of XLMTM, with improved force output, myonuclei positioning, myofibrillar structure, triad number, and excitation-contraction coupling. Tamoxifen normalizes the expression level of the XLMTM disease modifiers DNM2 and PI3KC2B, likely contributing to the phenotypic rescue. Our findings demonstrate that tamoxifen is a promising candidate for clinical evaluation in XLMTM patients.
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MESH Headings
- Animals
- Class II Phosphatidylinositol 3-Kinases/genetics
- Class II Phosphatidylinositol 3-Kinases/metabolism
- Disease Models, Animal
- Disease Progression
- Dynamin II/genetics
- Dynamin II/metabolism
- Electric Stimulation
- Excitation Contraction Coupling/drug effects
- Female
- Gene Expression/drug effects
- Genes, Lethal
- Humans
- Longevity/drug effects
- Male
- Mice
- Mice, Knockout
- Motor Activity/drug effects
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myofibrils/drug effects
- Myofibrils/metabolism
- Myofibrils/ultrastructure
- Myopathies, Structural, Congenital/drug therapy
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/metabolism
- Myopathies, Structural, Congenital/pathology
- Protective Agents/pharmacology
- Protein Tyrosine Phosphatases, Non-Receptor/deficiency
- Protein Tyrosine Phosphatases, Non-Receptor/genetics
- Tamoxifen/pharmacology
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Affiliation(s)
- Elinam Gayi
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Lausanne, University of Geneva, CMU 5-6, Rue Michel-Servet 1, Geneva, 1211, Switzerland
| | - Laurence A Neff
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Lausanne, University of Geneva, CMU 5-6, Rue Michel-Servet 1, Geneva, 1211, Switzerland
| | - Xènia Massana Muñoz
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, 67404, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, 67404, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, 67404, France
- Université de Strasbourg, Illkirch, 67404, France
| | - Hesham M Ismail
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Lausanne, University of Geneva, CMU 5-6, Rue Michel-Servet 1, Geneva, 1211, Switzerland
| | - Marta Sierra
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Lausanne, University of Geneva, CMU 5-6, Rue Michel-Servet 1, Geneva, 1211, Switzerland
| | - Thomas Mercier
- Division and Laboratory of Clinical Pharmacology, Service of Biomedicine, Department of Laboratories, Lausanne University Hospital, Lausanne, 1011, Switzerland
| | - Laurent A Décosterd
- Division and Laboratory of Clinical Pharmacology, Service of Biomedicine, Department of Laboratories, Lausanne University Hospital, Lausanne, 1011, Switzerland
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, 67404, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, 67404, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, 67404, France
- Université de Strasbourg, Illkirch, 67404, France
| | - Belinda S Cowling
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, 67404, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, 67404, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, 67404, France
- Université de Strasbourg, Illkirch, 67404, France
| | - Olivier M Dorchies
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Lausanne, University of Geneva, CMU 5-6, Rue Michel-Servet 1, Geneva, 1211, Switzerland.
| | - Leonardo Scapozza
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Lausanne, University of Geneva, CMU 5-6, Rue Michel-Servet 1, Geneva, 1211, Switzerland.
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12
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Abstract
Dynamin 2 (DNM2) belongs to a family of large GTPases that are well known for mediating membrane fission by oligomerizing at the neck of membrane invaginations. Autosomal dominant mutations in the ubiquitously expressed DNM2 cause 2 discrete neuromuscular diseases: autosomal dominant centronuclear myopathy (ADCNM) and dominant intermediate Charcot-Marie-Tooth neuropathy (CMT). CNM and CMT mutations may affect DNM2 in distinct manners: CNM mutations may cause protein hyperactivity with elevated GTPase and fission activities, while CMT mutations could impair DNM2 lipid binding and activity. DNM2 is also a modifier of the X-linked and autosomal recessive forms of CNM, as DNM2 protein levels are upregulated in animal models and patient muscle samples. Strikingly, reducing DNM2 has been shown to revert muscle phenotypes in preclinical models of CNM. As DNM2 emerges as the key player in CNM pathogenesis, the role(s) of DNM2 in skeletal muscle remains unclear. This review aims to provide insights into potential pathomechanisms related to DNM2-CNM mutations, and discuss exciting outcomes of current and future therapeutic approaches targeting DNM2 hyperactivity.
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Affiliation(s)
- Mo Zhao
- Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - Nika Maani
- Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
| | - James J Dowling
- Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada.
- Division of Neurology, Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada.
- Department of Pediatrics, University of Toronto, Toronto, ON, M5G 1X8, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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13
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Single Intramuscular Injection of AAV-shRNA Reduces DNM2 and Prevents Myotubular Myopathy in Mice. Mol Ther 2018; 26:1082-1092. [PMID: 29506908 DOI: 10.1016/j.ymthe.2018.02.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 02/02/2018] [Accepted: 02/09/2018] [Indexed: 12/28/2022] Open
Abstract
Myotubular myopathy, or X-linked centronuclear myopathy, is a severe muscle disorder representing a significant burden for patients and their families. It is clinically characterized by neonatal and severe muscle weakness and atrophy. Mutations in the myotubularin (MTM1) gene cause myotubular myopathy, and no specific curative treatment is available. We previously found that dynamin 2 (DNM2) is upregulated in both Mtm1 knockout and patient muscle samples, whereas its reduction through antisense oligonucleotides rescues the clinical and histopathological features of this myopathy in mice. Here, we propose a novel approach targeting Dnm2 mRNA. We screened and validated in vitro and in vivo several short hairpin RNA (shRNA) sequences that efficiently target Dnm2 mRNA. A single intramuscular injection of AAV-shDnm2 resulted in long-term reduction of DNM2 protein level and restored muscle force, mass, histology, and myofiber ultrastructure and prevented molecular defects linked to the disease. Our results demonstrate a robust DNM2 knockdown and provide an alternative strategy based on reduction of DNM2 to treat myotubular myopathy.
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14
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Bachmann C, Jungbluth H, Muntoni F, Manzur AY, Zorzato F, Treves S. Cellular, biochemical and molecular changes in muscles from patients with X-linked myotubular myopathy due to MTM1 mutations. Hum Mol Genet 2017; 26:320-332. [PMID: 28007904 DOI: 10.1093/hmg/ddw388] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/07/2016] [Indexed: 01/07/2023] Open
Abstract
Centronuclear myopathies are early-onset muscle diseases caused by mutations in several genes including MTM1, DNM2, BIN1, RYR1 and TTN. The most severe and often fatal X-linked form of myotubular myopathy (XLMTM) is caused by mutations in the gene encoding the ubiquitous lipid phosphatase myotubularin, an enzyme specifically dephosphorylating phosphatidylinositol-3-phosphate and phosphatidylinositol-3,5-bisphosphate. Because XLMTM patients have a predominantly muscle-specific phenotype a number of pathogenic mechanisms have been proposed, including a direct effect of the accumulated lipid on the skeletal muscle calcium channel ryanodine receptor 1, a negative effect on the structure of intracellular organelles and defective autophagy. Animal models knocked out for MTM1 show severe reduction of ryanodine receptor 1 mediated calcium release but, since knocking out genes in animal models does not necessarily replicate the human phenotype, we considered it important to study directly the effect of MTM1 mutations on patient muscle cells. The results of the present study show that at the level of myotubes MTM1 mutations do not dramatically affect calcium homeostasis and calcium release mediated through the ryanodine receptor 1, though they do affect myotube size and nuclear content. On the other hand, mature muscles such as those obtained from patient muscle biopsies exhibit a significant decrease in expression of the ryanodine receptor 1, a decrease in muscle-specific microRNAs and a considerable up-regulation of histone deacetylase-4. We hypothesize that the latter events consequent to the primary genetic mutation, are the cause of the severe decrease in muscle strength that characterizes these patients.
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Affiliation(s)
- Christoph Bachmann
- Departments of Biomedicine and Anesthesia, Basel University Hospital, Basel University, Basel, Switzerland
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, St Thomas' Hospital, London, UK.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London, UK.,Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Diseases, Institute of Child Health, London, UK
| | - Adnan Y Manzur
- Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Diseases, Institute of Child Health, London, UK
| | - Francesco Zorzato
- Departments of Biomedicine and Anesthesia, Basel University Hospital, Basel University, Basel, Switzerland.,Department of Life Sciences, General Pathology section, University of Ferrara, Ferrara, Italy
| | - Susan Treves
- Departments of Biomedicine and Anesthesia, Basel University Hospital, Basel University, Basel, Switzerland.,Department of Life Sciences, General Pathology section, University of Ferrara, Ferrara, Italy
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15
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Ordulu Z, Kammin T, Brand H, Pillalamarri V, Redin CE, Collins RL, Blumenthal I, Hanscom C, Pereira S, Bradley I, Crandall BF, Gerrol P, Hayden MA, Hussain N, Kanengisser-Pines B, Kantarci S, Levy B, Macera MJ, Quintero-Rivera F, Spiegel E, Stevens B, Ulm JE, Warburton D, Wilkins-Haug LE, Yachelevich N, Gusella JF, Talkowski ME, Morton CC. Structural Chromosomal Rearrangements Require Nucleotide-Level Resolution: Lessons from Next-Generation Sequencing in Prenatal Diagnosis. Am J Hum Genet 2016; 99:1015-1033. [PMID: 27745839 PMCID: PMC5097935 DOI: 10.1016/j.ajhg.2016.08.022] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 08/26/2016] [Indexed: 12/27/2022] Open
Abstract
In this exciting era of "next-gen cytogenetics," integrating genomic sequencing into the prenatal diagnostic setting is possible within an actionable time frame and can provide precise delineation of balanced chromosomal rearrangements at the nucleotide level. Given the increased risk of congenital abnormalities in newborns with de novo balanced chromosomal rearrangements, comprehensive interpretation of breakpoints could substantially improve prediction of phenotypic outcomes and support perinatal medical care. Herein, we present and evaluate sequencing results of balanced chromosomal rearrangements in ten prenatal subjects with respect to the location of regulatory chromatin domains (topologically associated domains [TADs]). The genomic material from all subjects was interpreted to be "normal" by microarray analyses, and their rearrangements would not have been detected by cell-free DNA (cfDNA) screening. The findings of our systematic approach correlate with phenotypes of both pregnancies with untoward outcomes (5/10) and with healthy newborns (3/10). Two pregnancies, one with a chromosomal aberration predicted to be of unknown clinical significance and another one predicted to be likely benign, were terminated prior to phenotype-genotype correlation (2/10). We demonstrate that the clinical interpretation of structural rearrangements should not be limited to interruption, deletion, or duplication of specific genes and should also incorporate regulatory domains of the human genome with critical ramifications for the control of gene expression. As detailed in this study, our molecular approach to both detecting and interpreting the breakpoints of structural rearrangements yields unparalleled information in comparison to other commonly used first-tier diagnostic methods, such as non-invasive cfDNA screening and microarray analysis, to provide improved genetic counseling for phenotypic outcome in the prenatal setting.
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Affiliation(s)
- Zehra Ordulu
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Tammy Kammin
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Harrison Brand
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Boston, MA 02142, USA
| | - Vamsee Pillalamarri
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Claire E Redin
- Harvard Medical School, Boston, MA 02115, USA; Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Boston, MA 02142, USA
| | - Ryan L Collins
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Ian Blumenthal
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Carrie Hanscom
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Shahrin Pereira
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - India Bradley
- Department of Psychiatry, Prenatal Diagnosis Center, David Geffen School of Medicine, University of California, Los Angeles, Medical Plaza, Los Angeles, CA 90095, USA
| | - Barbara F Crandall
- Department of Psychiatry, Prenatal Diagnosis Center, David Geffen School of Medicine, University of California, Los Angeles, Medical Plaza, Los Angeles, CA 90095, USA
| | - Pamela Gerrol
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Mark A Hayden
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Naveed Hussain
- Department of Pediatrics, Connecticut Children's Medical Center, University of Connecticut, Farmington, CT 06030, USA
| | | | - Sibel Kantarci
- Department of Pathology and Laboratory Medicine, UCLA Clinical Genomics Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Brynn Levy
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Michael J Macera
- New York Presbyterian Hospital, Columbia University Medical Center, New York, NY 10032, USA
| | - Fabiola Quintero-Rivera
- Department of Pathology and Laboratory Medicine, UCLA Clinical Genomics Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Erica Spiegel
- Department of Maternal Fetal Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - Blair Stevens
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Janet E Ulm
- Regional Obstetrical Consultants, Chattanooga, TN 37403, USA
| | - Dorothy Warburton
- Department of Genetics and Development, Columbia University, New York, NY 10032, USA; Department of Pediatrics, Columbia University, New York, NY 10032, USA
| | - Louise E Wilkins-Haug
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Naomi Yachelevich
- Department of Pediatrics, Clinical Genetics Services, New York University School of Medicine, New York, NY 10003, USA
| | - James F Gusella
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Boston, MA 02142, USA; Department of Genetics, Harvard Medical School, Boson, MA 02115, USA
| | - Michael E Talkowski
- Harvard Medical School, Boston, MA 02115, USA; Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Boston, MA 02142, USA; Departments of Psychiatry and Pathology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Cynthia C Morton
- Department of Obstetrics, Gynecology, and Reproductive Biology, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Boston, MA 02142, USA; Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA; Division of Evolution and Genomic Science, School of Biological Sciences, University of Manchester, Manchester Academic Health Science Center, Manchester 03101, UK.
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16
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Smith BK, Renno MS, Green MM, Sexton TM, Lawson LA, Martin AD, Corti M, Byrne BJ. Respiratory motor function in individuals with centronuclear myopathies. Muscle Nerve 2015; 53:214-21. [PMID: 26351754 DOI: 10.1002/mus.24899] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2015] [Indexed: 12/13/2022]
Abstract
UNLABELLED I NTRODUCTION: Individuals with X-linked myotubular myopathy (XLMTM) and other centronuclear myopathies (CNMs) frequently have profound respiratory insufficiency that requires support early in life. Still, few quantitative data exist to characterize respiratory motor function in CNM. METHODS We evaluated the reliance upon mechanical ventilation (MV), ventilatory kinematics, unassisted tidal volumes, and maximal respiratory pressures in 14 individuals with CNMs, including 10 boys with XLMTM. RESULTS Thirteen participants required full-time, invasive MV. Maximal inspiratory pressures were higher in subjects who breathed unsupported at least 1 hour/day as compared with 24-hour MV users [33.7 (11.9-42.3) vs. 8.4 (6.0-10.9) cm H(2)O, P < 0.05]. Years of MV dependence correlated significantly with MEP (r = -0.715, P < 0.01). CONCLUSIONS Respiratory function in CNMs may be related to deconditioning from prolonged MV and/or differences in residual respiratory muscle strength. Results from this study may assist in evaluating severe respiratory insufficiency in neuromuscular clinical care and research.
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Affiliation(s)
- Barbara K Smith
- Department of Physical Therapy, University of Florida, P.O. Box 100154, Gainesville, Florida, 32610-0154, USA
| | - Markus S Renno
- Department of Pediatrics, Vanderbilt University, Nashville, Tennessee, USA
| | - Meghan M Green
- College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Terry M Sexton
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Lee Ann Lawson
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Anatole D Martin
- Department of Physical Therapy, University of Florida, P.O. Box 100154, Gainesville, Florida, 32610-0154, USA
| | - Manuela Corti
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
| | - Barry J Byrne
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
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17
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Childers MK, Beggs AH, Buj-Bello A. Gene replacement rescues severe muscle pathology and prolongs survival in myotubularin-deficient mice and dogs. ANNALS OF TRANSLATIONAL MEDICINE 2015; 3:257. [PMID: 26605303 DOI: 10.3978/j.issn.2305-5839.2015.10.01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Martin K Childers
- 1 Department of Rehabilitation Medicine, 2 Institute for Stem Cell and Regenerative Medicine, School of Medicine, University of Washington, Seattle, Washington 98109, USA ; 3 The Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA ; 4 Généthon, INSERM UMR 951, Evry, France
| | - Alan H Beggs
- 1 Department of Rehabilitation Medicine, 2 Institute for Stem Cell and Regenerative Medicine, School of Medicine, University of Washington, Seattle, Washington 98109, USA ; 3 The Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA ; 4 Généthon, INSERM UMR 951, Evry, France
| | - Ana Buj-Bello
- 1 Department of Rehabilitation Medicine, 2 Institute for Stem Cell and Regenerative Medicine, School of Medicine, University of Washington, Seattle, Washington 98109, USA ; 3 The Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA ; 4 Généthon, INSERM UMR 951, Evry, France
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18
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Longo G, Russo S, Novelli G, Sangiuolo F, D'Apice M. Mutation spectrum of the MTM1
gene in XLMTM patients: 10 years of experience in prenatal and postnatal diagnosis. Clin Genet 2015; 89:93-8. [DOI: 10.1111/cge.12674] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 09/01/2015] [Accepted: 09/01/2015] [Indexed: 11/28/2022]
Affiliation(s)
- G. Longo
- Department of Biomedicine and Prevention; University of Rome ‘Tor Vergata’; Rome Italy
| | - S. Russo
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
| | - G. Novelli
- Department of Biomedicine and Prevention; University of Rome ‘Tor Vergata’; Rome Italy
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
| | - F. Sangiuolo
- Department of Biomedicine and Prevention; University of Rome ‘Tor Vergata’; Rome Italy
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
| | - M.R. D'Apice
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
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19
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Hunter JM, Kiefer J, Balak CD, Jooma S, Ahearn ME, Hall JG, Baumbach-Reardon L. Review of X-linked syndromes with arthrogryposis or early contractures-aid to diagnosis and pathway identification. Am J Med Genet A 2015; 167A:931-73. [DOI: 10.1002/ajmg.a.36934] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 12/05/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Jesse M. Hunter
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Jeff Kiefer
- Knowledge Mining; Translational Genomics Research Institute; Phoenix Arizona
| | - Christopher D. Balak
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Sonya Jooma
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Mary Ellen Ahearn
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Judith G. Hall
- Departments of Medical Genetics and Pediatrics; University of British Columbia and BC Children's Hospital Vancouver; British Columbia Canada
| | - Lisa Baumbach-Reardon
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
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20
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Smith BK, Goddard M, Childers MK. Respiratory assessment in centronuclear myopathies. Muscle Nerve 2014; 50:315-26. [PMID: 24668768 DOI: 10.1002/mus.24249] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 12/23/2022]
Abstract
The centronuclear myopathies (CNMs) are a group of inherited neuromuscular disorders classified as congenital myopathies. While several causative genes have been identified, some patients do not harbor any of the currently known mutations. These diverse disorders have common histological features, which include a high proportion of centrally nucleated muscle fibers, and clinical attributes of muscle weakness and respiratory insufficiency. Respiratory problems in CNMs may manifest initially during sleep, but daytime symptoms, ineffective airway clearance, and hypoventilation predominate as more severe respiratory muscle dysfunction evolves. Respiratory muscle capacity can be evaluated using a variety of clinical tests selected with consideration for the age and baseline motor function of the patient. Similar clinical tests of respiratory function can also be incorporated into preclinical CNM canine models to offer insight for clinical trials. Because respiratory problems account for significant morbidity in patients, routine assessments of respiratory muscle function are discussed.
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Affiliation(s)
- Barbara K Smith
- Department of Physical Therapy, University of Florida, Gainesville, Florida, USA
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21
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Muhammad E, Reish O, Ohno Y, Scheetz T, Deluca A, Searby C, Regev M, Benyamini L, Fellig Y, Kihara A, Sheffield VC, Parvari R. Congenital myopathy is caused by mutation of HACD1. Hum Mol Genet 2013; 22:5229-36. [PMID: 23933735 PMCID: PMC3842179 DOI: 10.1093/hmg/ddt380] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Congenital myopathies are heterogeneous inherited diseases of muscle characterized by a range of distinctive histologic abnormalities. We have studied a consanguineous family with congenital myopathy. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous non-sense mutation in 3-hydroxyacyl-CoA dehydratase 1 (HACD1) in affected individuals. The mutation results in non-sense mediated decay of the HACD1 mRNA to 31% of control levels in patient muscle and completely abrogates the enzymatic activity of dehydration of 3-hydroxyacyl-CoA, the third step in the elongation of very long-chain fatty acids (VLCFAs). We describe clinical findings correlated with a deleterious mutation in a gene not previously known to be associated with congenital myopathy in humans. We suggest that the mutation in the HACD1 gene causes a reduction in the synthesis of VLCFAs, which are components of membrane lipids and participants in physiological processes, leading to congenital myopathy. These data indicate that HACD1 is necessary for muscle function.
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Affiliation(s)
- Emad Muhammad
- Shraga Segal Department of Microbiology, Immunology and Genetics, Faculty of Health Sciences and
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22
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Shichiji M, Biancalana V, Fardeau M, Hogrel JY, Osawa M, Laporte J, Romero NB. Extensive morphological and immunohistochemical characterization in myotubular myopathy. Brain Behav 2013; 3:476-86. [PMID: 24381816 PMCID: PMC3869686 DOI: 10.1002/brb3.147] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 11/30/2022] Open
Abstract
The X-linked myotubular myopathy (XLMTM) also called X-linked centronuclear myopathy is a rare congenital myopathy due to mutations in the MTM 1 gene encoding myotubularin. The disease gives rise to a severe muscle weakness in males at birth. The main muscle morphological characteristics (significant number of small muscle fibers with centralized nuclei and type 1 fiber predominance) are usually documented, but the sequence of formation and maintenance of this particular morphological pattern has not been extensively characterized in humans. In this study, we perform a reevaluation of morphological changes in skeletal muscle biopsies in severe XLMTM. We correlate the pathologic features observed in the muscle biopsies of 15 newborns with MTM 1-mutations according to the "adjusted-age" at the time of muscle biopsy, focusing on sequential analysis in the early period of the life (from 34 weeks of gestation to 3 months of age). We found a similar morphological pattern throughout the period analyzed; the proportion of myofibers with central nuclei was high in all muscle biopsies, independently of the muscle type, the age of the newborns at time of biopsy and the specific MTM 1 mutation. We did not observe a period free of morphological abnormalities in human skeletal muscle as observed in myotubularin-deficient mouse models. In addition, this study demonstrated some features of delayed maturation of the muscle fibers without any increase in the number of satellite cells, associated with a marked disorganization of the muscle T-tubules and cytoskeletal network in the skeletal muscle fibers.
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Affiliation(s)
- Minobu Shichiji
- Unité de Morphologie Neuromusculaire, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France ; Department of Pediatrics, Tokyo Woman's Medical University Tokyo, Japan
| | - Valérie Biancalana
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS, UMR7104, INSERM, U964, Collège de France, Université de Strasbourg Illkirch, France ; Laboratoire Diagnostic Génétique, Faculté de Médecine - CHRU Strasbourg, France
| | - Michel Fardeau
- Unité de Morphologie Neuromusculaire, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France ; Groupe Hospitalier-Universitaire La Pitié-Salpêtrière, AP-HP, Centre de référence des maladies neuromusculaires Paris-Est, Paris, France
| | - Jean-Yves Hogrel
- UPMC-Paris6 UR76, INSERM UMR974, CNRS UMR 7215, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France
| | - Makiko Osawa
- Department of Pediatrics, Tokyo Woman's Medical University Tokyo, Japan
| | - Jocelyn Laporte
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS, UMR7104, INSERM, U964, Collège de France, Université de Strasbourg Illkirch, France
| | - Norma Beatriz Romero
- Unité de Morphologie Neuromusculaire, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France ; Groupe Hospitalier-Universitaire La Pitié-Salpêtrière, AP-HP, Centre de référence des maladies neuromusculaires Paris-Est, Paris, France ; UPMC-Paris6 UR76, INSERM UMR974, CNRS UMR 7215, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France
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23
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Gupta VA, Hnia K, Smith LL, Gundry SR, McIntire JE, Shimazu J, Bass JR, Talbot EA, Amoasii L, Goldman NE, Laporte J, Beggs AH. Loss of catalytically inactive lipid phosphatase myotubularin-related protein 12 impairs myotubularin stability and promotes centronuclear myopathy in zebrafish. PLoS Genet 2013; 9:e1003583. [PMID: 23818870 PMCID: PMC3688503 DOI: 10.1371/journal.pgen.1003583] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 05/07/2013] [Indexed: 01/08/2023] Open
Abstract
X-linked myotubular myopathy (XLMTM) is a congenital disorder caused by mutations of the myotubularin gene, MTM1. Myotubularin belongs to a large family of conserved lipid phosphatases that include both catalytically active and inactive myotubularin-related proteins (i.e., "MTMRs"). Biochemically, catalytically inactive MTMRs have been shown to form heteroligomers with active members within the myotubularin family through protein-protein interactions. However, the pathophysiological significance of catalytically inactive MTMRs remains unknown in muscle. By in vitro as well as in vivo studies, we have identified that catalytically inactive myotubularin-related protein 12 (MTMR12) binds to myotubularin in skeletal muscle. Knockdown of the mtmr12 gene in zebrafish resulted in skeletal muscle defects and impaired motor function. Analysis of mtmr12 morphant fish showed pathological changes with central nucleation, disorganized Triads, myofiber hypotrophy and whorled membrane structures similar to those seen in X-linked myotubular myopathy. Biochemical studies showed that deficiency of MTMR12 results in reduced levels of myotubularin protein in zebrafish and mammalian C2C12 cells. Loss of myotubularin also resulted in reduction of MTMR12 protein in C2C12 cells, mice and humans. Moreover, XLMTM mutations within the myotubularin interaction domain disrupted binding to MTMR12 in cell culture. Analysis of human XLMTM patient myotubes showed that mutations that disrupt the interaction between myotubularin and MTMR12 proteins result in reduction of both myotubularin and MTMR12. These studies strongly support the concept that interactions between myotubularin and MTMR12 are required for the stability of their functional protein complex in normal skeletal muscles. This work highlights an important physiological function of catalytically inactive phosphatases in the pathophysiology of myotubular myopathy and suggests a novel therapeutic approach through identification of drugs that could stabilize the myotubularin-MTMR12 complex and hence ameliorate this disorder.
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Affiliation(s)
- Vandana A. Gupta
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Karim Hnia
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Inserm U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Chaire de Génétique Humaine, Illkirch, France
| | - Laura L. Smith
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Stacey R. Gundry
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jessica E. McIntire
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Junko Shimazu
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jessica R. Bass
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ethan A. Talbot
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Leonela Amoasii
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Inserm U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Chaire de Génétique Humaine, Illkirch, France
| | - Nathaniel E. Goldman
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Inserm U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Chaire de Génétique Humaine, Illkirch, France
| | - Alan H. Beggs
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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24
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Trump N, Cullup T, Verheij JBGM, Manzur A, Muntoni F, Abbs S, Jungbluth H. X-linked myotubular myopathy due to a complex rearrangement involving a duplication of MTM1 exon 10. Neuromuscul Disord 2011; 22:384-8. [PMID: 22153990 DOI: 10.1016/j.nmd.2011.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Revised: 11/11/2011] [Accepted: 11/16/2011] [Indexed: 11/18/2022]
Abstract
X-linked myotubular myopathy is a predominantly severe congenital myopathy with central nuclei on muscle biopsy due to mutations in the MTM1 gene encoding myotubularin. We report a boy with typical features of X-linked myotubular myopathy. Sequencing of the MTM1 gene did not reveal any causative mutations. Subsequent MLPA analysis identified a duplication of MTM1 exon 10 both in the patient and his mother. Additional quantitative fluorescent PCR and long-range PCR revealed an additional large deletion (2536bp) within intron 10, 143bp downstream of exon 10, and confirmed the duplication of exon 10. Our findings suggest that complex rearrangements have to be considered in typically affected males with X-linked myotubular myopathy.
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Affiliation(s)
- N Trump
- DNA Laboratory, GSTS Pathology, Guy's Hospital, London, UK.
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25
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Etv4 and Etv5 are required downstream of GDNF and Ret for kidney branching morphogenesis. Nat Genet 2009; 41:1295-302. [PMID: 19898483 PMCID: PMC2787691 DOI: 10.1038/ng.476] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 09/29/2009] [Indexed: 11/08/2022]
Abstract
Glial cell line-derived neurotrophic factor signaling through the Ret receptor tyrosine kinase is crucial for ureteric bud branching morphogenesis during kidney development, yet few of the downstream genes are known. Here we show that the ETS transcription factors Etv4 and Etv5 are positively regulated by Ret signaling in the ureteric bud tips. Mice lacking both Etv4 alleles and one Etv5 allele show either renal agenesis or severe hypodysplasia, whereas kidney development fails completely in double homozygotes. We identified several genes whose expression in the ureteric bud depends on Etv4 and Etv5, including Cxcr4, Myb, Met and Mmp14. Thus, Etv4 and Etv5 are key components of a gene network downstream of Ret that promotes and controls renal branching morphogenesis.
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26
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Abstract
The inositol phosphatase, MTMR4 (myotubularin-related protein 4), was identified as a novel interactor of the ubiquitin ligase Nedd4 (neural-precursor-cell-expressed developmentally down-regulated 4). hMTMR4 (human MTMR4) and Nedd4 co-immunoprecipitated and co-localized to late endosomes. The PY (Pro-Tyr) motif of hMTMR4 binds to WW (Trp-Trp) domains of hNedd4. MTMR4 expression was decreased in atrophying muscle, whereas Nedd4 expression was increased and hMTMR4 was ubiquitinated by hNedd4, suggesting that this novel interaction may underlie the biological process of muscle breakdown.
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27
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Jungbluth H, Wallgren-Pettersson C, Laporte J. Centronuclear (myotubular) myopathy. Orphanet J Rare Dis 2008; 3:26. [PMID: 18817572 PMCID: PMC2572588 DOI: 10.1186/1750-1172-3-26] [Citation(s) in RCA: 218] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 09/25/2008] [Indexed: 01/23/2023] Open
Abstract
Centronuclear myopathy (CNM) is an inherited neuromuscular disorder characterised by clinical features of a congenital myopathy and centrally placed nuclei on muscle biopsy. The incidence of X-linked myotubular myopathy is estimated at 2/100000 male births but epidemiological data for other forms are not currently available. The clinical picture is highly variable. The X-linked form usually gives rise to a severe phenotype in males presenting at birth with marked weakness and hypotonia, external ophthalmoplegia and respiratory failure. Signs of antenatal onset comprise reduced foetal movements, polyhydramnios and thinning of the ribs on chest radiographs; birth asphyxia may be the present. Affected infants are often macrosomic, with length above the 90th centile and large head circumference. Testes are frequently undescended. Both autosomal-recessive (AR) and autosomal-dominant (AD) forms differ from the X-linked form regarding age at onset, severity, clinical characteristics and prognosis. In general, AD forms have a later onset and milder course than the X-linked form, and the AR form is intermediate in both respects. Mutations in the myotubularin (MTM1) gene on chromosome Xq28 have been identified in the majority of patients with the X-linked recessive form, whilst AD and AR forms have been associated with mutations in the dynamin 2 (DNM2) gene on chromosome 19p13.2 and the amphiphysin 2 (BIN1) gene on chromosome 2q14, respectively. Single cases with features of CNM have been associated with mutations in the skeletal muscle ryanodine receptor (RYR1) and the hJUMPY (MTMR14) genes. Diagnosis is based on typical histopathological findings on muscle biopsy in combination with suggestive clinical features; muscle magnetic resonance imaging may complement clinical assessment and inform genetic testing in cases with equivocal features. Genetic counselling should be offered to all patients and families in whom a diagnosis of CNM has been made. The main differential diagnoses include congenital myotonic dystrophy and other conditions with severe neonatal hypotonia. Management of CNM is mainly supportive, based on a multidisciplinary approach. Whereas the X-linked form due to MTM1 mutations is often fatal in infancy, dominant forms due to DNM2 mutations and some cases of the recessive BIN1-related form appear to be associated with an overall more favourable prognosis.
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Affiliation(s)
- Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, St Thomas' Hospital, London, UK.
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28
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Abstract
Most congenital myopathies have been defined on account of the morphological findings in enzyme histochemical preparations. In effect, the diagnosis of this group of diseases continues to be made on the histological pattern of muscle biopsies. However, progress has been made in elucidating the molecular genetic background of several of the congenital myopathies. In this updated review we address those congenital myopathies for which gene defects and mutant proteins have been found (central core disease, nemaline myopathies, desminopathy, actinopathy, certain vacuolar myopathies, and myotubular myopathy) and the other disease with central nuclei (centronuclear myopathy).
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MESH Headings
- Actins/genetics
- Chromosome Mapping
- Desmin/genetics
- Humans
- Mutation
- Myopathies, Nemaline/genetics
- Myopathies, Nemaline/pathology
- Myopathies, Structural, Congenital/classification
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/pathology
- Myopathy, Central Core/genetics
- Myopathy, Central Core/pathology
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Affiliation(s)
- A Bornemann
- Institute of Brain Research, Eberhard-Karls University, Tübingen, Germany.
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29
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Pierson CR, Tomczak K, Agrawal P, Moghadaszadeh B, Beggs AH. X-linked myotubular and centronuclear myopathies. J Neuropathol Exp Neurol 2005; 64:555-64. [PMID: 16042307 DOI: 10.1097/01.jnen.0000171653.17213.2e] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Recent work has significantly enhanced our understanding of the centronuclear myopathies and, in particular, myotubular myopathy. These myopathies share similar morphologic appearances with other diseases, namely the presence of hypotrophic myofibers with prominent internalized or centrally placed nuclei. Early workers suggested that this alteration represented an arrest in myofiber maturation, while other hypotheses implicated either failure in myofiber maturation or neurogenic causes. Despite similarities in morphology, distinct patterns of inheritance and some differences in clinical features have been recognized among cases. A severe form, known as X-linked myotubular myopathy (XLMTM), presents at or near birth. Affected males have profound global hypotonia and weakness, accompanied by respiratory difficulties that often require ventilation. Most of these patients die in infancy or early childhood, but some survive into later childhood or even adulthood. The responsible gene (MTM1) has been cloned; it encodes a phosphoinositide lipid phosphatase known as myotubularin that appears to be important in muscle maintenance. In autosomal recessive centronuclear myopathy (AR CNM), the onset of weakness typically occurs in infancy or early childhood. Some investigators have divided AR CNM into 3 subgroups: 1) an early-onset form with ophthalmoparesis, 2) an early-onset form without ophthalmoparesis, and 3) a late-onset form without ophthalmoparesis. Clinically, autosomal dominant CNM (AD CNM) is relatively mild and usually presents in adults with a diffuse weakness that is slowly progressive and may be accompanied by muscle hypertrophy. Overall, the autosomal disorders are not as clinically uniform as XLMTM, which has made their genetic characterization more difficult. Currently the responsible gene(s) remain unknown. This review will explore the historical evolution in understanding of these myopathies and give an update on their histopathologic features, genetics and pathogenesis.
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MESH Headings
- Adult
- Diagnosis, Differential
- Female
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/pathology
- Genetic Diseases, X-Linked/physiopathology
- Humans
- Male
- Muscle, Skeletal/pathology
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/pathology
- Myopathies, Structural, Congenital/physiopathology
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases, Non-Receptor
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30
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Chanzy S, Routon MC, Moretti S, de Gennes C, Mselati JC. [Unusual good prognosis for X-linked myotubular myopathy]. Arch Pediatr 2003; 10:707-9. [PMID: 12922003 DOI: 10.1016/s0929-693x(03)00287-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recessive X-linked myotubular myopathy has recently been shown to be linked to the mutation of a gene located in the Xq28 region. Evolution is used to be considered as fatal but mild forms or forms with a better prognosis have been recorded since. We report a case in a patient, whose parents were warned of fatal outcome once the diagnosis was made during the neonatal period. The reaction of the parents was to avoid any relationship with medical care. Ten years later the patient was seen in relatively good health thus proving that the evolution was more favourable than anticipated.
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Affiliation(s)
- S Chanzy
- Service de pédiatrie et néonatologie, centre hospitalier d'Orsay, 91401 Orsay, France.
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31
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Jungbluth H, Sewry CA, Buj-Bello A, Kristiansen M, Ørstavik KH, Kelsey A, Manzur AY, Mercuri E, Wallgren-Pettersson C, Muntoni F. Early and severe presentation of X-linked myotubular myopathy in a girl with skewed X-inactivation. Neuromuscul Disord 2003; 13:55-9. [PMID: 12467733 DOI: 10.1016/s0960-8966(02)00194-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
X-linked myotubular myopathy is a severe congenital myopathy in males, caused by mutations in the myotubularin (MTM1) gene on chromosome Xq28. In heterozygous carriers of MTM1 mutations, clinical symptoms are usually absent or only mild. We report a 6-year-old girl presenting at birth with marked hypotonia and associated feeding and respiratory difficulties. A muscle biopsy performed at 5 months suggested a diagnosis of myotubular myopathy. On examination at 6 years she had marked facial weakness with bilateral ptosis and external ophthalmoplegia, severe axial and proximal weakness and a mild scoliosis. Muscle magnetic resonance imaging showed a distinctive pattern of muscle involvement. Molecular genetic investigation of the MTM1 gene identified a heterozygous mutation in exon 12. X-inactivation studies in lymphocytes showed an extremely skewed pattern (97:3). This case emphasizes that investigation of the MTM1 gene and X-inactivation studies are indicated in isolated females with histopathological and clinical findings suggestive of myotubular myopathy.
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Affiliation(s)
- H Jungbluth
- Department of Paediatrics, Dubowitz Neuromuscular Centre, Imperial College Faculty of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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32
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McEntagart M, Parsons G, Buj-Bello A, Biancalana V, Fenton I, Little M, Krawczak M, Thomas N, Herman G, Clarke A, Wallgren-Pettersson C. Genotype-phenotype correlations in X-linked myotubular myopathy. Neuromuscul Disord 2002; 12:939-46. [PMID: 12467749 DOI: 10.1016/s0960-8966(02)00153-0] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
X-linked myotubular myopathy is a severe congenital myopathy that presents in the neonatal period with profound hypotonia and an inability to establish spontaneous respiration. Usually death occurs in infancy from respiratory failure. However, there is phenotypic variability; a number of affected boys have achieved respiratory independence and become ambulatory. Disease-causing mutations have been identified throughout the MTM1 gene on Xq28. MTM1 encodes the protein myotubularin, which is expressed ubiquitously. The main objectives of this study were to establish whether the nature or site of the mutation in the MTM1 gene could predict severity of the disease and to investigate whether early intensive clinical intervention facilitated survival until spontaneous improvement occurred. An association was demonstrated between the presence of a non-truncating mutation of the MTM1 gene and the mild phenotype. However, many non-truncating mutations were also seen in association with the severe phenotype and these were not confined to recognized functional domains of the protein. This suggests that the use of mutation analysis to predict prognosis in the early period following diagnosis is limited. Unexpectedly, over 50 patients surviving for more than 1 year were identified in this study. Further information obtained on 40 of these cases revealed that 50% were receiving 24-h ventilatory support, while 27% were ventilated at night only. The high survival rate for this disorder therefore reflects intensive medical intervention without which the majority of these boys would not survive.
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MESH Headings
- Chi-Square Distribution
- Chromosomes, Human, X
- DNA Mutational Analysis
- Dosage Compensation, Genetic
- Exons
- Family Health
- Follow-Up Studies
- Genetic Diseases, X-Linked/genetics
- Genotype
- Humans
- Male
- Multigene Family
- Mutation
- Myopathies, Structural, Congenital/genetics
- Outcome Assessment, Health Care
- Phenotype
- Polymorphism, Single-Stranded Conformational
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases, Non-Receptor
- Statistics as Topic
- Survival Analysis
- Time Factors
- Ventilators, Mechanical/statistics & numerical data
- Ventilators, Mechanical/supply & distribution
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Affiliation(s)
- Meriel McEntagart
- Institute of Medical Genetics, University of Wales College of Medicine, Cardiff, UK.
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33
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Buj-Bello A, Laugel V, Messaddeq N, Zahreddine H, Laporte J, Pellissier JF, Mandel JL. The lipid phosphatase myotubularin is essential for skeletal muscle maintenance but not for myogenesis in mice. Proc Natl Acad Sci U S A 2002; 99:15060-5. [PMID: 12391329 PMCID: PMC524320 DOI: 10.1073/pnas.212498399] [Citation(s) in RCA: 180] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myotubularin is a ubiquitously expressed phosphatase that acts on phosphatidylinositol 3-monophosphate [PI(3)P], a lipid implicated in intracellular vesicle trafficking and autophagy. It is encoded by the MTM1 gene, which is mutated in X-linked myotubular myopathy (XLMTM), a muscular disorder characterized by generalized hypotonia and muscle weakness at birth leading to early death of most affected males. The disease was proposed to result from an arrest in myogenesis, as the skeletal muscle from patients contains hypotrophic fibers with centrally located nuclei that resemble fetal myotubes. To understand the physiopathological mechanism of XLMTM, we have generated mice lacking myotubularin by homologous recombination. These mice are viable, but their lifespan is severely reduced. They develop a generalized and progressive myopathy starting at around 4 weeks of age, with amyotrophy and accumulation of central nuclei in skeletal muscle fibers leading to death at 6-14 weeks. Contrary to expectations, we show that muscle differentiation in knockout mice occurs normally. We provide evidence that fibers with centralized myonuclei originate mainly from a structural maintenance defect affecting myotubularin-deficient muscle rather than a regenerative process. In addition, we demonstrate, through a conditional gene-targeting approach, that skeletal muscle is the primary target of murine XLMTM pathology. These mutant mice represent animal models for the human disease and will be a valuable tool for understanding the physiological role of myotubularin.
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Affiliation(s)
- Anna Buj-Bello
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université Louis Pasteur Strasbourg, 67404 Illkirch Cedex, France
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34
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Herman GE, Kopacz K, Zhao W, Mills PL, Metzenberg A, Das S. Characterization of mutations in fifty North American patients with X-linked myotubular myopathy. Hum Mutat 2002; 19:114-21. [PMID: 11793470 DOI: 10.1002/humu.10033] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
X-linked myotubular myopathy (MTM1) is a rare developmental disorder of skeletal muscle that is characterized by the presence of abnormal central nuclei in biopsy specimens taken from affected individuals. To date 133 different mutations have been identified in the MTM1 gene worldwide. We report here mutations detected in 50 additional U.S. families with biopsy-proven MTM1. Forty-one of the patients have not been described previously, including 18 with novel mutations. Eighty-eight percent of the mothers of sporadic cases that were studied were identified as carriers, extending the previously reported high-carrier frequency for this disorder. Clinical information collected on the majority of patients helps to further correlate genotype with phenotype, and implications of these data for genetic counseling in families are discussed.
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Affiliation(s)
- Gail E Herman
- Children's Research Institute and the Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA.
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35
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Dorchies OM, Laporte J, Wagner S, Hindelang C, Warter JM, Mandel JL, Poindron P. Normal innervation and differentiation of X-linked myotubular myopathy muscle cells in a nerve-muscle coculture system. Neuromuscul Disord 2001; 11:736-46. [PMID: 11595516 DOI: 10.1016/s0960-8966(01)00221-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To study the pathogenesis of X-linked recessive myotubular myopathy (XLMTM), we used a nerve-muscle coculture system which allows the reconstitution of functional motor units in vitro after coupling of human skeletal muscle cells with embryonic rat spinal cord explants. We used three skeletal muscle cell lines derived from subjects with known mutations in the MTM1 gene (two from embryonic tissues, associated with mutations predicted to give a severe phenotype, and one from a neonate still alive at 3 years 6 months and exhibiting a mild phenotype). We compared these three XLMTM muscle cell cultures with control cultures giving special attention to behaviour of living cocultures (formation of the myofibres, contractile activity, survival), expression of muscular markers (desmin, dystrophin, alpha-actinin, troponin-T, myosin heavy chain isoforms), and nerve-muscle interactions (expression and aggregation of the nicotinic acetylcholine receptors). We were unable to reproduce any 'myotubular' phenotype since XLMTM muscle cells behaved like normal cells with regard to all the investigated parameters. Our results suggest that XLMTM muscle might be intrinsically normal and emphasize the possible involvement of the myotubularin-deficient motor neurons in the development of the disease.
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MESH Headings
- Animals
- Antigens, Differentiation/biosynthesis
- Cell Differentiation/physiology
- Cell Survival
- Cells, Cultured
- Coculture Techniques
- Humans
- Male
- Muscle Contraction
- Muscle, Skeletal/embryology
- Muscle, Skeletal/innervation
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Mutation
- Myofibrils/metabolism
- Myofibrils/ultrastructure
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/metabolism
- Myopathies, Structural, Congenital/pathology
- Nerve Tissue/cytology
- Nerve Tissue/embryology
- Nerve Tissue/metabolism
- Phenotype
- Protein Tyrosine Phosphatases/genetics
- Protein Tyrosine Phosphatases, Non-Receptor
- Rats
- Receptors, Nicotinic/metabolism
- Spinal Cord/cytology
- Spinal Cord/embryology
- X Chromosome/genetics
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Affiliation(s)
- O M Dorchies
- Laboratoire de Pathologie des Communications entre Cellules Nerveuses et Musculaires (UPRES 2308), UFR des Sciences Pharmaceutiques, BP 24, 74 route du Rhin, 67401 Illkirch Cedex, France
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36
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Wallgren-Pettersson C. 72nd ENMC International Workshop: myotubular myopathy 1-3 October 1999, Hilversum, The Netherlands. Neuromuscul Disord 2000; 10:525-9. [PMID: 10996786 DOI: 10.1016/s0960-8966(00)00124-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- C Wallgren-Pettersson
- Department of Medical Genetics, University of Helsinki, P.O. Box 211, 00251, Helsinki, Finland
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37
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Laporte J, Biancalana V, Tanner SM, Kress W, Schneider V, Wallgren-Pettersson C, Herger F, Buj-Bello A, Blondeau F, Liechti-Gallati S, Mandel JL. MTM1 mutations in X-linked myotubular myopathy. Hum Mutat 2000; 15:393-409. [PMID: 10790201 DOI: 10.1002/(sici)1098-1004(200005)15:5<393::aid-humu1>3.0.co;2-r] [Citation(s) in RCA: 155] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
X-linked myotubular myopathy (XLMTM; MIM# 310400) is a severe congenital muscle disorder caused by mutations in the MTM1 gene. This gene encodes a dual-specificity phosphatase named myotubularin, defining a large gene family highly conserved through evolution (which includes the putative anti-phosphatase Sbf1/hMTMR5). We report 29 mutations in novel cases, including 16 mutations not described before. To date, 198 mutations have been identified in unrelated families, accounting for 133 different disease-associated mutations which are widespread throughout the gene. Most point mutations are truncating, but 26% (35/133) are missense mutations affecting residues conserved in the Drosophila ortholog and in the homologous MTMR1 gene. Three recurrent mutations affect 17% of the patients, and a total of 21 different mutations were found in several independent families. The frequency of female carriers appears higher than expected (only 17% are de novo mutations). While most truncating mutations cause the severe and early lethal phenotype, some missense mutations are associated with milder forms and prolonged survival (up to 54 years).
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Affiliation(s)
- J Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
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