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Zaharieva IT, Thor MG, Oates EC, van Karnebeek C, Hendson G, Blom E, Witting N, Rasmussen M, Gabbett MT, Ravenscroft G, Sframeli M, Suetterlin K, Sarkozy A, D'Argenzio L, Hartley L, Matthews E, Pitt M, Vissing J, Ballegaard M, Krarup C, Slørdahl A, Halvorsen H, Ye XC, Zhang LH, Løkken N, Werlauff U, Abdelsayed M, Davis MR, Feng L, Phadke R, Sewry CA, Morgan JE, Laing NG, Vallance H, Ruben P, Hanna MG, Lewis S, Kamsteeg EJ, Männikkö R, Muntoni F. Loss-of-function mutations in SCN4A cause severe foetal hypokinesia or 'classical' congenital myopathy. Brain 2015; 139:674-91. [PMID: 26700687 PMCID: PMC4766374 DOI: 10.1093/brain/awv352] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/13/2015] [Indexed: 11/15/2022] Open
Abstract
See Cannon (doi:
10.1093/brain/awv400
) for a scientific commentary on this article.
Congenital myopathies are a clinically and genetically heterogeneous group of muscle disorders characterized by congenital or early-onset hypotonia and muscle weakness, and specific pathological features on muscle biopsy. The phenotype ranges from foetal akinesia resulting in
in utero
or neonatal mortality, to milder disorders that are not life-limiting. Over the past decade, more than 20 new congenital myopathy genes have been identified. Most encode proteins involved in muscle contraction; however, mutations in ion channel-encoding genes are increasingly being recognized as a cause of this group of disorders.
SCN4A
encodes the α-subunit of the skeletal muscle voltage-gated sodium channel (Na
v
1.4). This channel is essential for the generation and propagation of the muscle action potential crucial to muscle contraction. Dominant
SCN4A
gain-of-function mutations are a well-established cause of myotonia and periodic paralysis. Using whole exome sequencing, we identified homozygous or compound heterozygous
SCN4A
mutations in a cohort of 11 individuals from six unrelated kindreds with congenital myopathy. Affected members developed
in utero
- or neonatal-onset muscle weakness of variable severity. In seven cases, severe muscle weakness resulted in death during the third trimester or shortly after birth. The remaining four cases had marked congenital or neonatal-onset hypotonia and weakness associated with mild-to-moderate facial and neck weakness, significant neonatal-onset respiratory and swallowing difficulties and childhood-onset spinal deformities. All four surviving cohort members experienced clinical improvement in the first decade of life. Muscle biopsies showed myopathic features including fibre size variability, presence of fibrofatty tissue of varying severity, without specific structural abnormalities. Electrophysiology suggested a myopathic process, without myotonia.
In vitro
functional assessment in HEK293 cells of the impact of the identified
SCN4A
mutations showed loss-of-function of the mutant Na
v
1.4 channels. All, apart from one, of the mutations either caused fully non-functional channels, or resulted in a reduced channel activity. Each of the affected cases carried at least one full loss-of-function mutation. In five out of six families, a second loss-of-function mutation was present on the trans allele. These functional results provide convincing evidence for the pathogenicity of the identified mutations and suggest that different degrees of loss-of-function in mutant Na
v
1.4 channels are associated with attenuation of the skeletal muscle action potential amplitude to a level insufficient to support normal muscle function. The results demonstrate that recessive loss-of-function
SCN4A
mutations should be considered in patients with a congenital myopathy.
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Affiliation(s)
- Irina T Zaharieva
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Michael G Thor
- 2 MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Emily C Oates
- 3 Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Westmead, New South Wales, 2145, Australia 4 Discipline of Paediatrics and Child Health, Faculty of Medicine, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Clara van Karnebeek
- 5 Department of Pediatrics, Child and Family Research Institute, Centre for Molecular Medicine and Therapeutics, University of British Columbia, 4480 Oak Street, Vancouver, B.C. V6H 3V4, Canada
| | - Glenda Hendson
- 4 Discipline of Paediatrics and Child Health, Faculty of Medicine, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Eveline Blom
- 5 Department of Pediatrics, Child and Family Research Institute, Centre for Molecular Medicine and Therapeutics, University of British Columbia, 4480 Oak Street, Vancouver, B.C. V6H 3V4, Canada
| | - Nanna Witting
- 8 Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, DK2100 Copenhagen, Denmark
| | - Magnhild Rasmussen
- 9 Department of Clinical Neuroscience for Children, Oslo University Hospital, 0424, Oslo, Norway 10 Unit for Hereditary Neuromuscular Disorders, Oslo University Hospital, 0424, Oslo, Norway
| | - Michael T Gabbett
- 11 Genetic Health Queensland, Royal Brisbane & Women's Hospital & Griffith University, Brisbane, Australia
| | - Gianina Ravenscroft
- 12 The Harry Perkins Institute of Medical Research, Centre for Medical Research, The University of Western Australia, Perth, 6009, Western Australia, Australia
| | - Maria Sframeli
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Karen Suetterlin
- 2 MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Anna Sarkozy
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Luigi D'Argenzio
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Louise Hartley
- 13 Department of Child Health, University Hospital Wales, Cardiff, CF14 4XW, UK
| | - Emma Matthews
- 2 MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Matthew Pitt
- 14 Neurophysiology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
| | - John Vissing
- 8 Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, DK2100 Copenhagen, Denmark
| | - Martin Ballegaard
- 15 Department of Clinical Neurophysiology, Rigshospitalet, University of Copenhagen, DK2100 Copenhagen, Denmark
| | - Christian Krarup
- 15 Department of Clinical Neurophysiology, Rigshospitalet, University of Copenhagen, DK2100 Copenhagen, Denmark
| | - Andreas Slørdahl
- 16 Children's Clinic, St.Olavs hospital, Trondheim University Hospital, 7006 Trondheim, Norway
| | - Hanne Halvorsen
- 17 Department of Pathology, University Hospital of North Norway, 9038 Tromsø, Norway
| | - Xin Cynthia Ye
- 5 Department of Pediatrics, Child and Family Research Institute, Centre for Molecular Medicine and Therapeutics, University of British Columbia, 4480 Oak Street, Vancouver, B.C. V6H 3V4, Canada
| | - Lin-Hua Zhang
- 5 Department of Pediatrics, Child and Family Research Institute, Centre for Molecular Medicine and Therapeutics, University of British Columbia, 4480 Oak Street, Vancouver, B.C. V6H 3V4, Canada
| | - Nicoline Løkken
- 8 Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, DK2100 Copenhagen, Denmark
| | - Ulla Werlauff
- 18 The Danish National Rehabilitation Center for Neuromuscular Diseases, Aarhus, 8000 Denmark
| | - Mena Abdelsayed
- 19 Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, V5A 1S6, Canada
| | - Mark R Davis
- 20 Department Molecular Genetics, Pathwest, QEII Medical Centre, Nedlands 6009, Western Australia, Australia
| | - Lucy Feng
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Rahul Phadke
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Caroline A Sewry
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK
| | - Jennifer E Morgan
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK 2 MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Nigel G Laing
- 12 The Harry Perkins Institute of Medical Research, Centre for Medical Research, The University of Western Australia, Perth, 6009, Western Australia, Australia
| | - Hilary Vallance
- 5 Department of Pediatrics, Child and Family Research Institute, Centre for Molecular Medicine and Therapeutics, University of British Columbia, 4480 Oak Street, Vancouver, B.C. V6H 3V4, Canada
| | - Peter Ruben
- 19 Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, V5A 1S6, Canada
| | - Michael G Hanna
- 2 MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Suzanne Lewis
- 5 Department of Pediatrics, Child and Family Research Institute, Centre for Molecular Medicine and Therapeutics, University of British Columbia, 4480 Oak Street, Vancouver, B.C. V6H 3V4, Canada
| | - Erik-Jan Kamsteeg
- 21 Department of Human Genetics, Radboud University Medical Center, Nijmegen, 6500HB, The Netherlands
| | - Roope Männikkö
- 2 MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Francesco Muntoni
- 1 Dubowitz Neuromuscular Centre, UCL Institute of Child Health, London, WC1N 1EH, UK 2 MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, 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] [What about the content of this article? (0)] [Affiliation(s)] [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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