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Remiche G, Kadhim H, Abramowicz M, Mavroudakis N, Monnier N, Lunardi J. A novel large deletion in the RYR1 gene in a Belgian family with late-onset and recessive core myopathy. Neuromuscul Disord 2015; 25:397-402. [PMID: 25747005 DOI: 10.1016/j.nmd.2015.01.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 01/20/2015] [Accepted: 01/25/2015] [Indexed: 11/15/2022]
Abstract
We report a novel and particularly unusual type of mutation, namely, large deletion in the RYR1 gene, in a Belgian family with myopathy: Patients were found to be compound heterozygous and presented a clinico-pathological phenotype characterized by late-onset and recessive myopathy with cores. We depict the clinical, electrophysiological, pathological and molecular genetic characteristics of family members. To date, large deletions in the RYR1 gene have been reported in only two cases. Both involved different mutations and, in sharp contrast to our cases, presented with a very early-onset, neonatal, and a very severe or lethal phenotype. Overview of reported clinico-pathologic phenotypes, also highlights the rarity of combined late-onset/recessive co-occurrence in this group of myopathies with cores. Finally, this report underlines the broadening spectrum in this group of myopathologic disorders and highlights the concept of 'RYR1-associated/related core myopathies'.
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Affiliation(s)
- Gauthier Remiche
- Centre de Référence Neuromusculaire, Service de Neurologie, Hôpital Erasme, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium
| | - Hazim Kadhim
- Unité de Neuropathologie, CHU Brugmann, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium.
| | - Marc Abramowicz
- Service de Génétique médicale, Hôpital Erasme, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium
| | - Nicolas Mavroudakis
- Centre de Référence Neuromusculaire, Service de Neurologie, Hôpital Erasme, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium
| | - Nicole Monnier
- Biochimie et Génétique moléculaire, Institut de Biologie et Pathologie, CHU Grenoble, France
| | - Joël Lunardi
- Biochimie et Génétique moléculaire, Institut de Biologie et Pathologie, CHU Grenoble, France
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Ravenscroft G, Laing NG, Bönnemann CG. Pathophysiological concepts in the congenital myopathies: blurring the boundaries, sharpening the focus. ACTA ACUST UNITED AC 2014; 138:246-68. [PMID: 25552303 DOI: 10.1093/brain/awu368] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The congenital myopathies are a diverse group of genetic skeletal muscle diseases, which typically present at birth or in early infancy. There are multiple modes of inheritance and degrees of severity (ranging from foetal akinesia, through lethality in the newborn period to milder early and later onset cases). Classically, the congenital myopathies are defined by skeletal muscle dysfunction and a non-dystrophic muscle biopsy with the presence of one or more characteristic histological features. However, mutations in multiple different genes can cause the same pathology and mutations in the same gene can cause multiple different pathologies. This is becoming ever more apparent now that, with the increasing use of next generation sequencing, a genetic diagnosis is achieved for a greater number of patients. Thus, considerable genetic and pathological overlap is emerging, blurring the classically established boundaries. At the same time, some of the pathophysiological concepts underlying the congenital myopathies are moving into sharper focus. Here we explore whether our emerging understanding of disease pathogenesis and underlying pathophysiological mechanisms, rather than a strictly gene-centric approach, will provide grounds for a different and perhaps complementary grouping of the congenital myopathies, that at the same time could help instil the development of shared potential therapeutic approaches. Stemming from recent advances in the congenital myopathy field, five key pathophysiology themes have emerged: defects in (i) sarcolemmal and intracellular membrane remodelling and excitation-contraction coupling; (ii) mitochondrial distribution and function; (iii) myofibrillar force generation; (iv) atrophy; and (v) autophagy. Based on numerous emerging lines of evidence from recent studies in cell lines and patient tissues, mouse models and zebrafish highlighting these unifying pathophysiological themes, here we review the congenital myopathies in relation to these emerging pathophysiological concepts, highlighting both areas of overlap between established entities, as well as areas of distinction within single gene disorders.
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Affiliation(s)
- Gianina Ravenscroft
- 1 Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Nigel G Laing
- 1 Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Carsten G Bönnemann
- 2 National Institute of Neurological Disorders and Stroke/NIH, Porter Neuroscience Research Centre, Bethesda, MD, USA
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Jungbluth H, Gautel M. Pathogenic mechanisms in centronuclear myopathies. Front Aging Neurosci 2014; 6:339. [PMID: 25566070 PMCID: PMC4271577 DOI: 10.3389/fnagi.2014.00339] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/02/2014] [Indexed: 12/30/2022] Open
Abstract
Centronuclear myopathies (CNMs) are a genetically heterogeneous group of inherited neuromuscular disorders characterized by clinical features of a congenital myopathy and abundant central nuclei as the most prominent histopathological feature. The most common forms of congenital myopathies with central nuclei have been attributed to X-linked recessive mutations in the MTM1 gene encoding myotubularin (“X-linked myotubular myopathy”), autosomal-dominant mutations in the DNM2 gene encoding dynamin-2 and the BIN1 gene encoding amphiphysin-2 (also named bridging integrator-1, BIN1, or SH3P9), and autosomal-recessive mutations in BIN1, the RYR1 gene encoding the skeletal muscle ryanodine receptor, and the TTN gene encoding titin. Models to study and rescue the affected cellular pathways are now available in yeast, C. elegans, drosophila, zebrafish, mouse, and dog. Defects in membrane trafficking have emerged as a key pathogenic mechanisms, with aberrant T-tubule formation, abnormalities of triadic assembly, and disturbance of the excitation–contraction machinery the main downstream effects studied to date. Abnormal autophagy has recently been recognized as another important collateral of defective membrane trafficking in different genetic forms of CNM, suggesting an intriguing link to primary disorders of defective autophagy with overlapping histopathological features. The following review will provide an overview of clinical, histopathological, and genetic aspects of the CNMs in the context of the key pathogenic mechanism, outline unresolved questions, and indicate promising future lines of enquiry.
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Affiliation(s)
- Heinz Jungbluth
- Neuromuscular Service, Department of Paediatric Neurology, 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 and Cardiovascular Division, King's College London BHF Centre of Research Excellence , London , UK
| | - Mathias Gautel
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, King's College London BHF Centre of Research Excellence , London , UK
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McKie AB, Alsaedi A, Vogt J, Stuurman KE, Weiss MM, Shakeel H, Tee L, Morgan NV, Nikkels PGJ, van Haaften G, Park SM, van der Smagt JJ, Bugiani M, Maher ER. Germline mutations in RYR1 are associated with foetal akinesia deformation sequence/lethal multiple pterygium syndrome. Acta Neuropathol Commun 2014; 2:148. [PMID: 25476234 PMCID: PMC4271450 DOI: 10.1186/s40478-014-0148-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/06/2014] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Foetal akinesia deformation sequence syndrome (FADS) is a genetically heterogeneous disorder characterised by the combination of foetal akinesia and developmental defects which may include pterygia (joint webbing). Traditionally multiple pterygium syndrome (MPS) has been divided into two forms: prenatally lethal (LMPS) and non-lethal Escobar type (EVMPS) types. Interestingly, FADS, LMPS and EVMPS may be allelic e.g. each of these phenotypes may result from mutations in the foetal acetylcholine receptor gamma subunit gene (CHRNG). Many cases of FADS and MPS do not have a mutation in a known FADS/MPS gene and we undertook molecular genetic studies to identify novel causes of these phenotypes. RESULTS After mapping a novel locus for FADS/LMPS to chromosome 19, we identified a homozygous null mutation in the RYR1 gene in a consanguineous kindred with recurrent LMPS pregnancies. Resequencing of RYR1 in a cohort of 66 unrelated probands with FADS/LMPS/EVMPS (36 with FADS/LMPS and 30 with EVMPS) revealed two additional homozygous mutations (in frame deletions). The overall frequency of RYR1 mutations in probands with FADS/LMPS was 8.3%. CONCLUSIONS Our findings report, for the first time, a homozygous RYR1 null mutation and expand the range of RYR1-related phenotypes to include early lethal FADS/LMPS. We suggest that RYR1 mutation analysis should be performed in cases of severe FADS/LMPS even in the absence of specific histopathological indicators of RYR1-related disease.
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Affiliation(s)
- Arthur B McKie
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
| | - Atif Alsaedi
- Centre for Rare Diseases and Personalised Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women's Hospital, Birmingham, B15 2TG, UK.
| | - Kyra E Stuurman
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands.
| | - Marjan M Weiss
- Department of Clinical Genetics, VU University Medical Center, Amsterdam, The Netherlands.
| | - Hassan Shakeel
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
| | - Louise Tee
- Centre for Rare Diseases and Personalised Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Neil V Morgan
- Centre for Rare Diseases and Personalised Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
| | - Peter G J Nikkels
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Gijs van Haaften
- Department of Medical Genetics, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands.
| | - Soo-Mi Park
- Department of Clinical Genetics, Addenbrooke's Treatment Centre, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge, CB2 0QQ, UK.
| | - Jasper J van der Smagt
- Department of Medical Genetics, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands.
| | - Marianna Bugiani
- Department of Pathology, VU University Medical Center, Amsterdam, the Netherlands.
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge, CB2 0QQ, UK.
- Centre for Rare Diseases and Personalised Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
- Department of Clinical Genetics, Addenbrooke's Treatment Centre, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge, CB2 0QQ, UK.
- Department of Medical Genetics, School of Clinical Medicine, University of Cambridge, Addenbrooke's Treatment Centre, Cambridge Biomedical Campus, Box 238, Cambridge, CB2 0QQ, United Kingdom.
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Martin F, Kana V, Mori AC, Fischer D, Parkin N, Boltshauser E, Rushing EJ, Klein A. Neurofibromatosis type 1 (NF1) with an unusually severe phenotype due to digeny for NF1 and ryanodine receptor 1 associated myopathy. Eur J Pediatr 2014; 173:1691-4. [PMID: 24706162 DOI: 10.1007/s00431-014-2314-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 02/21/2014] [Accepted: 03/26/2014] [Indexed: 11/30/2022]
Abstract
UNLABELLED We describe a 5-year-old girl with marked hypotonia, poor feeding and reduced facial expression since birth. Congenital myopathy was suspected; muscle biopsy showed unspecific type 1 fibre predominance. The possibility of a ryanodine receptor 1 gene (RYR1)-associated myopathy was considered, but not further investigated. At the age of 2 years, she presented with exophthalmos. Brain MRI revealed optic pathway glioma. On clinical examination, she had six café-au-lait spots, thus fulfilling the diagnostic criteria for neurofibromatosis type 1 (NF1). The hypotonia was then attributed to NF1. At the age of 3 years, she developed scoliosis and had an unusually severe motor delay for NF1, as she was not able to walk independently. Dual pathology was suspected, and muscle MRI showed the typical pattern for RYR1-related myopathy. This was genetically confirmed with the discovery of two heterozygous mutations. CONCLUSION NF1 is one of the most frequent genetic diseases in children. RYR1-related myopathy is one of the most frequent causes of congenital myopathy. The combination of these two pathologies has not yet been described. In cases of unusual presentations or clinical course, the possibility of genetic "double trouble" should be considered.
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Affiliation(s)
- Florence Martin
- Department of Paediatric Neurology, Kantonsspital Winterthur, Winterthur, Switzerland,
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Colombo I, Scoto M, Manzur AY, Robb SA, Maggi L, Gowda V, Cullup T, Yau M, Phadke R, Sewry C, Jungbluth H, Muntoni F. Congenital myopathies: Natural history of a large pediatric cohort. Neurology 2014; 84:28-35. [PMID: 25428687 DOI: 10.1212/wnl.0000000000001110] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE To assess the natural history of congenital myopathies (CMs) due to different genotypes. METHODS Retrospective cross-sectional study based on case-note review of 125 patients affected by CM, followed at a single pediatric neuromuscular center, between 1984 and 2012. RESULTS Genetic characterization was achieved in 99 of 125 cases (79.2%), with RYR1 most frequently implicated (44/125). Neonatal/infantile onset was observed in 76%. At birth, 30.4% required respiratory support, and 25.2% nasogastric feeding. Twelve percent died, mainly within the first year, associated with mutations in ACTA1, MTM1, or KLHL40. All RYR1-mutated cases survived and did not require long-term ventilator support including those with severe neonatal onset; however, recessive cases were more likely to require gastrostomy insertion (p = 0.0028) compared with dominant cases. Independent ambulation was achieved in 74.1% of all patients; 62.9% were late walkers. Among ambulant patients, 9% eventually became wheelchair-dependent. Scoliosis of variable severity was reported in 40%, with 1/3 of (both ambulant and nonambulant) patients requiring surgery. Bulbar involvement was present in 46.4% and required gastrostomy placement in 28.8% (at a mean age of 2.7 years). Respiratory impairment of variable severity was a feature in 64.1%; approximately half of these patients required nocturnal noninvasive ventilation due to respiratory failure (at a mean age of 8.5 years). CONCLUSIONS We describe the long-term outcome of a large cohort of patients with CMs. While overall course is stable, we demonstrate a wide clinical spectrum with motor deterioration in a subset of cases. Severity in the neonatal/infantile period is critical for survival, with clear genotype-phenotype correlations that may inform future counseling.
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Affiliation(s)
- Irene Colombo
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Mariacristina Scoto
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Adnan Y Manzur
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Stephanie A Robb
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Lorenzo Maggi
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Vasantha Gowda
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Thomas Cullup
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Michael Yau
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Rahul Phadke
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Caroline Sewry
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Heinz Jungbluth
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK
| | - Francesco Muntoni
- From the Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders (I.C., M.S., A.Y.M., S.A.R., V.G., C.S., F.M.), University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, UK; Neuromuscular Unit (I.C.), Department of Neurological Sciences, IRCCS Foundation Cà Granda, Ospedale Maggiore Policlinico, Dino Ferrari Centre, Milan, University of Milan; Muscle Pathology and Neuroimmunology Unit (L.M.), Foundation IRCCS Neurological Institute C. Besta, Milan, Italy; DNA Laboratory (T.C., M.Y.), GSTS Pathology, Guy's Hospital, London; University College London Department of Neurology (R.P.), National Hospital for Neurology and Neurosurgery, London; Wolfson Centre for Inherited Neuromuscular Diseases RJAH (C.S.), Oswestry; Department of Paediatric Neurology (H.J.), Evelina Children's Hospital, London; Randall Division for Cell and Molecular Biophysics (H.J.), Muscle Signalling Section, King's College, London; and Clinical Neuroscience Division (H.J.), IoP, London, UK.
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Lau K, Van Petegem F. Crystal structures of wild type and disease mutant forms of the ryanodine receptor SPRY2 domain. Nat Commun 2014; 5:5397. [DOI: 10.1038/ncomms6397] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 09/26/2014] [Indexed: 12/16/2022] Open
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108
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Abstract
The triad is a skeletal muscle substructure responsible for the regulation of excitation-contraction coupling. It is formed by the close apposition of the T-tubule and the terminal sarcoplasmic reticulum. A rapidly growing list of skeletal myopathies, here referred to as triadopathies, are caused by gene mutations in components of the triad. These disorders, at their root, are caused by defects in excitation contraction coupling and intracellular calcium homeostasis. Secondary abnormalities in triad structure and/or function are also reported in several muscle diseases, most notably certain muscular dystrophies. This review highlights the current understanding of both primary and secondary triadopathies, and identifies important concepts yet to be fully addressed in the field. The emphasis of the review is both on the pathogenesis of triadopathies and their potential treatment.
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Affiliation(s)
- James J Dowling
- Division of Neurology and Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, ON, Canada,
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109
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From the Journal archives: Hereditary aspects of malignant hyperthermia. Can J Anaesth 2014; 61:1122-5. [DOI: 10.1007/s12630-014-0233-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 08/25/2014] [Indexed: 11/26/2022] Open
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Fernandez-Fuente M, Terracciano CM, Martin-Duque P, Brown SC, Vassaux G, Piercy RJ. Calcium homeostasis in myogenic differentiation factor 1 (MyoD)-transformed, virally-transduced, skin-derived equine myotubes. PLoS One 2014; 9:e105971. [PMID: 25148524 PMCID: PMC4141859 DOI: 10.1371/journal.pone.0105971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/30/2014] [Indexed: 11/19/2022] Open
Abstract
Dysfunctional skeletal muscle calcium homeostasis plays a central role in the pathophysiology of several human and animal skeletal muscle disorders, in particular, genetic disorders associated with ryanodine receptor 1 (RYR1) mutations, such as malignant hyperthermia, central core disease, multiminicore disease and certain centronuclear myopathies. In addition, aberrant skeletal muscle calcium handling is believed to play a pivotal role in the highly prevalent disorder of Thoroughbred racehorses, known as Recurrent Exertional Rhabdomyolysis. Traditionally, such defects were studied in human and equine subjects by examining the contractile responses of biopsied muscle strips exposed to caffeine, a potent RYR1 agonist. However, this test is not widely available and, due to its invasive nature, is potentially less suitable for valuable animals in training or in the human paediatric setting. Furthermore, increasingly, RYR1 gene polymorphisms (of unknown pathogenicity and significance) are being identified through next generation sequencing projects. Consequently, we have investigated a less invasive test that can be used to study calcium homeostasis in cultured, skin-derived fibroblasts that are converted to the muscle lineage by viral transduction with a MyoD (myogenic differentiation 1) transgene. Similar models have been utilised to examine calcium homeostasis in human patient cells, however, to date, there has been no detailed assessment of the cells’ calcium homeostasis, and in particular, the responses to agonists and antagonists of RYR1. Here we describe experiments conducted to assess calcium handling of the cells and examine responses to treatment with dantrolene, a drug commonly used for prophylaxis of recurrent exertional rhabdomyolysis in horses and malignant hyperthermia in humans.
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Affiliation(s)
- Marta Fernandez-Fuente
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, United Kingdom
| | - Cesare M. Terracciano
- Laboratory of Cell Electrophysiology, Imperial College London, Myocardial Function, National Heart and Lung Institute, Hammersmith Hospital, London, United Kingdom
| | - Pilar Martin-Duque
- Universidad Francisco de Vitoria, Facultad de Ciencias Biosanitarias: Pozuelo de Alarcón (Madrid), Madrid, Spain
| | - Susan C. Brown
- Comparative Biomedical Sciences, Royal Veterinary College, London, United Kingdom
| | - Georges Vassaux
- Laboratoire TIRO, UMRE 4320, iBEB, DSV, Commissariat a’ l’Energie Atomique, Nice, France
| | - Richard J. Piercy
- Comparative Neuromuscular Diseases Laboratory, Department of Clinical Sciences and Services, Royal Veterinary College, London, United Kingdom
- * E-mail:
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111
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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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112
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Illingworth MA, Main M, Pitt M, Feng L, Sewry CA, Gunny R, Vorstman E, Beeson D, Manzur A, Muntoni F, Robb SA. RYR1-related congenital myopathy with fatigable weakness, responding to pyridostigimine. Neuromuscul Disord 2014; 24:707-12. [PMID: 24951453 DOI: 10.1016/j.nmd.2014.05.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 04/30/2014] [Accepted: 05/06/2014] [Indexed: 10/25/2022]
Abstract
The spectrum of RYR1 mutation associated disease encompasses congenital myopathies, exercise induced rhabdomyolysis, malignant hyperthermia susceptibility and King-Denborough syndrome. We report the clinical phenotype of two siblings who presented in infancy with hypotonia and striking fatigable ptosis. Their response to pyridostigimine was striking, but genetic screening for congenital myasthenic syndromes was negative, prompting further evaluation. Muscle MRI was abnormal with a selective pattern of involvement evocative of RYR1-related myopathy. This directed sequencing of the RYR1 gene, which revealed two heterozygous c.6721C>T (p.Arg2241X) nonsense mutations and novel c.8888T>C (p.Leu2963Pro) mutations in both siblings. These cases broaden the RYR1-related disease spectrum to include a myasthenic-like phenotype, including partial response to pyridostigimine. RYR1-related myopathy should be considered in the presence of fatigable weakness especially if muscle imaging demonstrates structural abnormalities. Single fibre electromyography can also be helpful in cases like this.
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Affiliation(s)
- M A Illingworth
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK
| | - M Main
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK
| | - M Pitt
- Department of Clinical Neurophysiology, Great Ormond Street Hospital, London, UK
| | - L Feng
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK
| | - C A Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK; Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, UK
| | - R Gunny
- Department of Radiology, Great Ormond Street Hospital, London, UK
| | - E Vorstman
- Department of Paediatrics, Gloucester Royal Hospital, Gloucester, UK
| | - D Beeson
- Weatherall Institute, John Radcliffe Hospital, Oxford, UK
| | - A Manzur
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK
| | - F Muntoni
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK.
| | - S A Robb
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK
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113
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Marttila M, Lehtokari VL, Marston S, Nyman TA, Barnerias C, Beggs AH, Bertini E, Ceyhan-Birsoy O, Cintas P, Gerard M, Gilbert-Dussardier B, Hogue JS, Longman C, Eymard B, Frydman M, Kang PB, Klinge L, Kolski H, Lochmüller H, Magy L, Manel V, Mayer M, Mercuri E, North KN, Peudenier-Robert S, Pihko H, Probst FJ, Reisin R, Stewart W, Taratuto AL, de Visser M, Wilichowski E, Winer J, Nowak K, Laing NG, Winder TL, Monnier N, Clarke NF, Pelin K, Grönholm M, Wallgren-Pettersson C. Mutation update and genotype-phenotype correlations of novel and previously described mutations in TPM2 and TPM3 causing congenital myopathies. Hum Mutat 2014; 35:779-90. [PMID: 24692096 DOI: 10.1002/humu.22554] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 03/17/2014] [Indexed: 01/14/2023]
Abstract
Mutations affecting skeletal muscle isoforms of the tropomyosin genes may cause nemaline myopathy, cap myopathy, core-rod myopathy, congenital fiber-type disproportion, distal arthrogryposes, and Escobar syndrome. We correlate the clinical picture of these diseases with novel (19) and previously reported (31) mutations of the TPM2 and TPM3 genes. Included are altogether 93 families: 53 with TPM2 mutations and 40 with TPM3 mutations. Thirty distinct pathogenic variants of TPM2 and 20 of TPM3 have been published or listed in the Leiden Open Variant Database (http://www.dmd.nl/). Most are heterozygous changes associated with autosomal-dominant disease. Patients with TPM2 mutations tended to present with milder symptoms than those with TPM3 mutations, DA being present only in the TPM2 group. Previous studies have shown that five of the mutations in TPM2 and one in TPM3 cause increased Ca(2+) sensitivity resulting in a hypercontractile molecular phenotype. Patients with hypercontractile phenotype more often had contractures of the limb joints (18/19) and jaw (6/19) than those with nonhypercontractile ones (2/22 and 1/22), whereas patients with the non-hypercontractile molecular phenotype more often (19/22) had axial contractures than the hypercontractile group (7/19). Our in silico predictions show that most mutations affect tropomyosin-actin association or tropomyosin head-to-tail binding.
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Affiliation(s)
- Minttu Marttila
- The Folkhälsan Institute of Genetics and the Department of Medical Genetics, University of Helsinki, Haartman Institute, Biomedicum Helsinki, Finland
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Bönnemann CG, Wang CH, Quijano-Roy S, Deconinck N, Bertini E, Ferreiro A, Muntoni F, Sewry C, Béroud C, Mathews KD, Moore SA, Bellini J, Rutkowski A, North KN. Diagnostic approach to the congenital muscular dystrophies. Neuromuscul Disord 2014; 24:289-311. [PMID: 24581957 PMCID: PMC5258110 DOI: 10.1016/j.nmd.2013.12.011] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/23/2013] [Accepted: 12/31/2013] [Indexed: 12/14/2022]
Abstract
Congenital muscular dystrophies (CMDs) are early onset disorders of muscle with histological features suggesting a dystrophic process. The congenital muscular dystrophies as a group encompass great clinical and genetic heterogeneity so that achieving an accurate genetic diagnosis has become increasingly challenging, even in the age of next generation sequencing. In this document we review the diagnostic features, differential diagnostic considerations and available diagnostic tools for the various CMD subtypes and provide a systematic guide to the use of these resources for achieving an accurate molecular diagnosis. An International Committee on the Standard of Care for Congenital Muscular Dystrophies composed of experts on various aspects relevant to the CMDs performed a review of the available literature as well as of the unpublished expertise represented by the members of the committee and their contacts. This process was refined by two rounds of online surveys and followed by a three-day meeting at which the conclusions were presented and further refined. The combined consensus summarized in this document allows the physician to recognize the presence of a CMD in a child with weakness based on history, clinical examination, muscle biopsy results, and imaging. It will be helpful in suspecting a specific CMD subtype in order to prioritize testing to arrive at a final genetic diagnosis.
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Affiliation(s)
- Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
| | - Ching H Wang
- Driscoll Children's Hospital, Corpus Christi, TX, United States
| | - Susana Quijano-Roy
- Hôpital Raymond Poincaré, Garches, and UFR des sciences de la santé Simone Veil (UVSQ), France
| | - Nicolas Deconinck
- Hôpital Universitaire des Enfants Reine Fabiola, Brussels and Ghent University Hospital, Ghent, Belgium
| | | | - Ana Ferreiro
- UMR787 INSERM/UPMC and Reference Center for Neuromuscular Disorders, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, United Kingdom
| | - Caroline Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, United Kingdom
| | - Christophe Béroud
- INSERM U827, Laboratoire de Génétique Moleculaire, Montpellier, France
| | | | | | - Jonathan Bellini
- Stanford University School of Medicine, Stanford, CA, United States
| | | | - Kathryn N North
- Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
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115
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Shaaban S, Ramos-Platt L, Gilles FH, Chan WM, Andrews C, De Girolami U, Demer J, Engle EC. RYR1 mutations as a cause of ophthalmoplegia, facial weakness, and malignant hyperthermia. JAMA Ophthalmol 2014; 131:1532-40. [PMID: 24091937 DOI: 10.1001/jamaophthalmol.2013.4392] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Total ophthalmoplegia can result from ryanodine receptor 1 (RYR1) mutations without overt associated skeletal myopathy. Patients carrying RYR1 mutations are at high risk of developing malignant hyperthermia. Ophthalmologists should be familiar with these important clinical associations. OBJECTIVE To determine the genetic cause of congenital ptosis, ophthalmoplegia, facial paralysis, and mild hypotonia segregating in 2 pedigrees diagnosed with atypical Moebius syndrome or congenital fibrosis of the extraocular muscles. DESIGN, SETTING, AND PARTICIPANTS Clinical data including medical and family histories were collected at research laboratories at Boston Children's Hospital and Jules Stein Eye Institute (Engle and Demer labs) for affected and unaffected family members from 2 pedigrees in which patients presented with total ophthalmoplegia, facial weakness, and myopathy. INTERVENTION Homozygosity mapping and whole-exome sequencing were conducted to identify causative mutations in affected family members. Histories, physical examinations, and clinical data were reviewed. MAIN OUTCOME AND MEASURE Mutations in RYR1. RESULTS Missense mutations resulting in 2 homozygous RYR1 amino acid substitutions (E989G and R3772W) and 2 compound heterozygous RYR1 substitutions (H283R and R3772W) were identified in a consanguineous and a nonconsanguineous pedigree, respectively. Orbital magnetic resonance imaging revealed marked hypoplasia of extraocular muscles and intraorbital cranial nerves. Skeletal muscle biopsy specimens revealed nonspecific myopathic changes. Clinically, the patients' ophthalmoplegia and facial weakness were far more significant than their hypotonia and limb weakness and were accompanied by an unrecognized susceptibility to malignant hyperthermia. CONCLUSIONS AND RELEVANCE Affected children presenting with severe congenital ophthalmoplegia and facial weakness in the setting of only mild skeletal myopathy harbored recessive mutations in RYR1, encoding the ryanodine receptor 1, and were susceptible to malignant hyperthermia. While ophthalmoplegia occurs rarely in RYR1-related myopathies, these children were atypical because they lacked significant weakness, respiratory insufficiency, or scoliosis. RYR1-associated myopathies should be included in the differential diagnosis of congenital ophthalmoplegia and facial weakness, even without clinical skeletal myopathy. These patients should also be considered susceptible to malignant hyperthermia, a life-threatening anesthetic complication avoidable if anticipated presurgically.
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Affiliation(s)
- Sherin Shaaban
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts2F. B. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts3Program in Genomics, Boston Children's Hospital, Boston, Massachusetts4Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts5Dubai Harvard Foundation for Medical Research, Boston, Massachusetts
| | - Leigh Ramos-Platt
- Division of Pediatric Neurology, Children's Hospital Los Angeles, Los Angeles, California
| | - Floyd H Gilles
- Division of Pathology (Neuropathology), Children's Hospital Los Angeles, Los Angeles, California
| | - Wai-Man Chan
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts3Program in Genomics, Boston Children's Hospital, Boston, Massachusetts8Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - Caroline Andrews
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts2F. B. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts8Howard Hughes Medical Institute, Chevy Chase, Maryland
| | - Umberto De Girolami
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts10Department of Pathology, Harvard Medical School, Boston, Massachusetts11Division of Neuropathology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Joseph Demer
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles13Department of Neurology, Jules Stein Eye Institute, University of California, Los Angeles14Department of Bioengineering, Jules Stein Eye Institute, University of California, Los Angeles15Neuroscience Interdepartmental Programs, Jules Stein Eye Institute, University of California, Los Angeles
| | - Elizabeth C Engle
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts2F. B. Kirby Neurobiology Center, Boston Children's Hospital, Boston, Massachusetts3Program in Genomics, Boston Children's Hospital, Boston, Massachusetts4Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts8Howard Hughes Medical Institute, Chevy Chase, Maryland16Department of Medicine (Genetics), Boston Children's Hospital, Boston, Massachusetts17Department of Ophthalmology, Boston Children's Hospital, Boston, Massachusetts18Department of Neurology, Harvard Medical School, Boston, Massachusetts19Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts20Broad Institute of MIT and Harvard, Cambridge, Massachusetts
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116
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Abstract
BACKGROUND Malignant hyperthermia susceptibility (MHS) is a life-threatening, inherited disorder of muscle calcium metabolism, triggered by anesthetics and depolarizing muscle relaxants. An unselected cohort was screened for MHS mutations using exome sequencing. The aim of this study was to pilot a strategy for the RYR1 and CACNA1S genes. METHODS Exome sequencing was performed on 870 volunteers not ascertained for MHS. Variants in RYR1 and CACNA1S were annotated using an algorithm that filtered results based on mutation type, frequency, and information in mutation databases. Variants were scored on a six-point pathogenicity scale. Medical histories and pedigrees were reviewed for malignant hyperthermia and related disorders. RESULTS The authors identified 70 RYR1 and 53 CACNA1S variants among 870 exomes. Sixty-three RYR1 and 41 CACNA1S variants passed the quality and frequency metrics but the authors excluded synonymous variants. In RYR1, the authors identified 65 missense mutations, one nonsense, two that affected splicing, and one non-frameshift indel. In CACNA1S, 48 missense, one frameshift deletion, one splicing, and one non-frameshift indel were identified. RYR1 variants predicted to be pathogenic for MHS were found in three participants without medical or family histories of MHS. Numerous variants, previously described as pathogenic in mutation databases, were reclassified by the authors as being of unknown pathogenicity. CONCLUSIONS Exome sequencing can identify asymptomatic patients at risk for MHS, although the interpretation of exome variants can be challenging. The use of exome sequencing in unselected cohorts is an important tool to understand the prevalence and penetrance of MHS, a critical challenge for the field.
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Amburgey K, Bailey A, Hwang JH, Tarnopolsky MA, Bonnemann CG, Medne L, Mathews KD, Collins J, Daube JR, Wellman GP, Callaghan B, Clarke NF, Dowling JJ. Genotype-phenotype correlations in recessive RYR1-related myopathies. Orphanet J Rare Dis 2013; 8:117. [PMID: 23919265 PMCID: PMC3751094 DOI: 10.1186/1750-1172-8-117] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 08/01/2013] [Indexed: 11/10/2022] Open
Abstract
Background RYR1 mutations are typically associated with core myopathies and are the most common overall cause of congenital myopathy. Dominant mutations are most often associated with central core disease and malignant hyperthermia, and genotype-phenotype patterns have emerged from the study of these mutations that have contributed to the understanding of disease pathogenesis. The recent availability of genetic testing for the entire RYR1 coding sequence has led to a dramatic expansion in the identification of recessive mutations in core myopathies and other congenital myopathies. To date, no clear patterns have been identified in these recessive mutations, though no systematic examination has yet been performed. Methods In this study, we investigated genotype-phenotype correlations in a large combined cohort of unpublished (n = 14) and previously reported (n = 92) recessive RYR1 cases. Results Overall examination of this cohort revealed nearly 50% of cases to be non-core myopathy related. Our most significant finding was that hypomorphic mutations (mutations expected to diminish RyR1 expression) were enriched in patients with severe clinical phenotypes. We also determined that hypomorphic mutations were more likely to be encountered in non-central core myopathies. With analysis of the location of non-hypomorphic mutations, we found that missense mutations were generally enriched in the MH/CCD hotspots and specifically enriched in the selectivity filter of the channel pore. Conclusions These results support a hypothesis that loss of protein function is a key predictive disease parameter. In addition, they suggest that decreased RyR1 expression may dictate non-core related pathology though, data on protein expression was limited and should be confirmed in a larger cohort. Lastly, the results implicate abnormal ion conductance through the channel pore in the pathogenesis in recessive core myopathies. Overall, our findings represent a comprehensive analysis of genotype-phenotype associations in recessive RYR1-myopathies.
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Affiliation(s)
- Kimberly Amburgey
- Department of Pediatrics, Taubman Medical Research Institute, University of Michigan Medical Center, 5019 A, Alfred Taubman Biomedical Science Research Building, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
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118
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Variable myopathic presentation in a single family with novel skeletal RYR1 mutation. PLoS One 2013; 8:e69296. [PMID: 23894444 PMCID: PMC3722152 DOI: 10.1371/journal.pone.0069296] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 06/11/2013] [Indexed: 01/24/2023] Open
Abstract
We describe an autosomal recessive heterogeneous congenital myopathy in a large consanguineous family. The disease is characterized by variable severity, progressive course in 3 of 4 patients, myopathic face without ophthalmoplegia and proximal muscle weakness. Absence of cores was noted in all patients. Genome wide linkage analysis revealed a single locus on chromosome 19q13 with Zmax = 3.86 at θ = 0.0 and homozygosity of the polymorphic markers at this locus in patients. Direct sequencing of the main candidate gene within the candidate region, RYR1, was performed. A novel homozygous A to G nucleotide substitution (p.Y3016C) within exon 60 of the RYR1 gene was found in patients. ARMS PCR was used to screen for the mutation in all available family members and in an additional 150 healthy individuals. This procedure confirmed sequence analysis and did not reveal the A to G mutation (p.Y3016C) in 300 chromosomes from healthy individuals. Functional analysis on EBV immortalized cell lines showed no effect of the mutation on RyR1 pharmacological activation or the content of intracellular Ca2+ stores. Western blot analysis demonstrated a significant reduction of the RyR1 protein in the patient’s muscle concomitant with a reduction of the DHPRα1.1 protein. This novel mutation resulting in RyR1 protein decrease causes heterogeneous clinical presentation, including slow progression course and absence of centrally localized cores on muscle biopsy. We suggest that RYR1 related myopathy should be considered in a wide variety of clinical and pathological presentation in childhood myopathies.
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119
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Dlamini N, Voermans NC, Lillis S, Stewart K, Kamsteeg EJ, Drost G, Quinlivan R, Snoeck M, Norwood F, Radunovic A, Straub V, Roberts M, Vrancken AFJE, van der Pol WL, de Coo RIFM, Manzur AY, Yau S, Abbs S, King A, Lammens M, Hopkins PM, Mohammed S, Treves S, Muntoni F, Wraige E, Davis MR, van Engelen B, Jungbluth H. Mutations in RYR1 are a common cause of exertional myalgia and rhabdomyolysis. Neuromuscul Disord 2013; 23:540-8. [PMID: 23628358 DOI: 10.1016/j.nmd.2013.03.008] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 03/08/2013] [Accepted: 03/12/2013] [Indexed: 12/23/2022]
Abstract
Mutations in the skeletal muscle ryanodine receptor (RYR1) gene are a common cause of neuromuscular disease, ranging from various congenital myopathies to the malignant hyperthermia (MH) susceptibility trait without associated weakness. We sequenced RYR1 in 39 unrelated families with rhabdomyolysis and/or exertional myalgia, frequent presentations in the neuromuscular clinic that often remain unexplained despite extensive investigations. We identified 9 heterozygous RYR1 mutations/variants in 14 families, 5 of them (p.Lys1393Arg; p.Gly2434Arg; p.Thr4288_Ala4290dup; p.Ala4295Val; and p.Arg4737Gln) previously associated with MH. Index cases presented from 3 to 45 years with rhabdomyolysis, with or without exertional myalgia (n=12), or isolated exertional myalgia (n=2). Rhabdomyolysis was commonly triggered by exercise and heat and, less frequently, viral infections, alcohol and drugs. Most cases were normally strong and had no personal MH history. Inconsistent additional features included heat intolerance, and cold-induced muscle stiffness. Muscle biopsies showed mainly subtle changes. Familial RYR1 mutations were confirmed in relatives with similar or no symptoms. These findings suggest that RYR1 mutations may account for a substantial proportion of patients presenting with unexplained rhabdomyolysis and/or exertional myalgia. Associated clinico-pathological features may be subtle and require a high degree of suspicion. Additional family studies are paramount in order to identify potentially MH susceptible relatives.
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Affiliation(s)
- N Dlamini
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK
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Bharucha-Goebel DX, Santi M, Medne L, Zukosky K, Zukosky K, Dastgir J, Shieh PB, Winder T, Tennekoon G, Finkel RS, Dowling JJ, Monnier N, Bönnemann CG. Severe congenital RYR1-associated myopathy: the expanding clinicopathologic and genetic spectrum. Neurology 2013; 80:1584-9. [PMID: 23553484 DOI: 10.1212/wnl.0b013e3182900380] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To report a series of 11 patients on the severe end of the spectrum of ryanodine receptor 1 (RYR1) gene-related myopathy, in order to expand the clinical, histologic, and genetic heterogeneity associated with this group of patients. METHODS Eleven patients evaluated in the neonatal period with severe neonatal-onset RYR1-associated myopathy confirmed by genetic testing were ascertained. Clinical features, molecular testing results, muscle imaging, and muscle histology are reviewed. RESULTS Clinical features associated with the severe neonatal presentation of RYR1-associated myopathy included decreased fetal movement, hypotonia, poor feeding, respiratory involvement, arthrogryposis, and ophthalmoplegia in 3 patients, and femur fractures or hip dislocation at birth. Four patients had dominant RYR1 mutations, and 7 had recessive RYR1 mutations. One patient had a cleft palate, and another a congenital rigid spine phenotype-findings not previously described in the literature in patients with early-onset RYR1 mutations. Six patients who underwent muscle ultrasound showed relative sparing of the rectus femoris muscle. Histologically, all patients with dominant mutations had classic central cores on muscle biopsy. Patients with recessive mutations showed great histologic heterogeneity, including fibrosis, variation in fiber size, skewed fiber typing, very small fibers, and nuclear internalization with or without ill-defined cores. CONCLUSIONS This series confirms and expands the clinical and histologic variability associated with severe congenital RYR1-associated myopathy. Both dominant and recessive mutations of the RYR1 gene can result in a severe neonatal-onset phenotype, but more clinical and histologic heterogeneity has been seen in those with recessive RYR1 gene mutations. Central cores are not obligatory histologic features in recessive RYR1 mutations. Sparing of the rectus femoris muscle on imaging should prompt evaluation for RYR1-associated myopathy in the appropriate clinical context.
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Maggi L, Scoto M, Cirak S, Robb SA, Klein A, Lillis S, Cullup T, Feng L, Manzur AY, Sewry CA, Abbs S, Jungbluth H, Muntoni F. Congenital myopathies--clinical features and frequency of individual subtypes diagnosed over a 5-year period in the United Kingdom. Neuromuscul Disord 2013; 23:195-205. [PMID: 23394784 DOI: 10.1016/j.nmd.2013.01.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 11/15/2012] [Accepted: 01/03/2013] [Indexed: 12/14/2022]
Abstract
The congenital myopathies are a group of inherited neuromuscular disorders mainly defined on the basis of characteristic histopathological features. We analysed 66 patients assessed at a single centre over a 5 year period. Of the 54 patients where muscle biopsy was available, 29 (54%) had a core myopathy (central core disease, multi-minicore disease), 9 (17%) had nemaline myopathy, 7 (13%) had myotubular/centronuclear myopathy, 2 (4%) had congenital fibre type disproportion, 6 (11%) had isolated type 1 predominance and 1 (2%) had a mixed core-rod myopathy. Of the 44 patients with a genetic diagnosis, RYR1 was mutated in 26 (59%), ACTA1 in 7 (16%), SEPN1 in 7 (16%), MTM1 in 2 (5%), NEB in 1 (2%) and TPM3 in 1 (2%). Clinically, 77% of patients older than 18 months could walk independently. 35% of all patients required ventilatory support and/or enteral feeding. Clinical course was stable or improved in 57/66 (86%) patients, whilst 4 (6%) got worse and 5 (8%) died. These findings indicate that core myopathies are the most common form of congenital myopathies and that more than half can be attributed to RYR1 mutations. The underlying genetic defect remains to be identified in 1/3 of congenital myopathies cases.
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Affiliation(s)
- L Maggi
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital for Children Foundation Trust, London, UK
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TREAT-NMD workshop: pattern recognition in genetic muscle diseases using muscle MRI: 25-26 February 2011, Rome, Italy. Neuromuscul Disord 2013; 22 Suppl 2:S42-53. [PMID: 22980768 DOI: 10.1016/j.nmd.2012.08.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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A novel late-onset axial myopathy associated with mutations in the skeletal muscle ryanodine receptor (RYR1) gene. J Neurol 2013; 260:1504-10. [DOI: 10.1007/s00415-012-6817-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 11/27/2022]
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Ramachandran S, Chakraborty A, Xu L, Mei Y, Samsó M, Dokholyan NV, Meissner G. Structural determinants of skeletal muscle ryanodine receptor gating. J Biol Chem 2013; 288:6154-65. [PMID: 23319589 DOI: 10.1074/jbc.m112.433789] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ryanodine receptor type 1 (RyR1) releases Ca(2+) from intracellular stores upon nerve impulse to trigger skeletal muscle contraction. Effector binding at the cytoplasmic domain tightly controls gating of the pore domain of RyR1 to release Ca(2+). However, the molecular mechanism that links effector binding to channel gating is unknown due to lack of structural data. Here, we used a combination of computational and electrophysiological methods and cryo-EM densities to generate structural models of the open and closed states of RyR1. Using our structural models, we identified an interface between the pore-lining helix (Tyr-4912-Glu-4948) and a linker helix (Val-4830-Val-4841) that lies parallel to the cytoplasmic membrane leaflet. To test the hypothesis that this interface controls RyR1 gating, we designed mutations in the linker helix to stabilize either the open (V4830W and T4840W) or closed (H4832W and G4834W) state and validated them using single channel experiments. To further confirm this interface, we designed mutations in the pore-lining helix to stabilize the closed state (Q4947N, Q4947T, and Q4947S), which we also validated using single channel experiments. The channel conductance and selectivity of the mutations that we designed in the linker and pore-lining helices were indistinguishable from those of WT RyR1, demonstrating our ability to modulate RyR1 gating without affecting ion permeation. Our integrated computational and experimental approach significantly advances the understanding of the structure and function of an unusually large ion channel.
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Affiliation(s)
- Srinivas Ramachandran
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599-7260, USA
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Kraeva N, Zvaritch E, Rossi AE, Goonasekera SA, Zaid H, Frodis W, Kraev A, Dirksen RT, Maclennan DH, Riazi S. Novel excitation-contraction uncoupled RYR1 mutations in patients with central core disease. Neuromuscul Disord 2012. [PMID: 23183335 DOI: 10.1016/j.nmd.2012.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Central core disease, one of the most common congenital myopathies in humans, has been linked to mutations in the RYR1 gene encoding the Ca(2+) release channel of the sarcoplasmic reticulum (RyR1). Functional analyses showed that disease-associated RYR1 mutations led to impairment of skeletal muscle Ca(2+) homeostasis; however, thorough understanding of the molecular mechanisms underlying central core disease and other RyR1-related conditions is still lacking. We screened by sequencing the complete RYR1 transcripts in ten unrelated patients with central core disease and identified five novel, p.M4640R, p.L4647P, p.F4808L, p.D4918N and p.F4941C, and four recurrent mutations. Four of the novel mutations involved amino acid residues that were positioned within putative transmembrane segments of the RyR1. The pathogenic character of the identified mutations was demonstrated by bioinformatic analyses and by the in vitro functional studies in HEK293 cells and RYR1-null (dyspedic) myotubes. Characterization of Ca(2+) channel properties of RyR1s carrying one recurrent and two novel mutations upholds the view that diminished intracellular Ca(2+) release caused by impaired Ca(2+) channel gating and/or Ca(2+) permeability is an important component of central core disease etiology. This study expands the list of functionally characterized disease-associated RyR1 mutations, increasing the value of genetic diagnosis for RyR1-related disorders.
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Affiliation(s)
- Natalia Kraeva
- Malignant Hyperthermia Investigation Unit, Toronto General Hospital, University Health Network, Toronto, ON, Canada M5G 2C4
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