1
|
Recessive MYH7-related myopathy in two families. Neuromuscul Disord 2019; 29:456-467. [PMID: 31130376 DOI: 10.1016/j.nmd.2019.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 02/08/2023]
Abstract
Myopathies due to recessive MYH7 mutations are exceedingly rare, reported in only two families to date. We describe three patients from two families (from Australia and the UK) with a myopathy caused by recessive mutations in MYH7. The Australian family was homozygous for a c.5134C > T, p.Arg1712Trp mutation, whilst the UK patient was compound heterozygous for a truncating (c.4699C > T; p.Gln1567*) and a missense variant (c.4664A > G; p.Glu1555Gly). All three patients shared key clinical features, including infancy/childhood onset, pronounced axial/proximal weakness, spinal rigidity, severe scoliosis, and normal cardiac function. There was progressive respiratory impairment necessitating non-invasive ventilation despite preserved ambulation, a combination of features often seen in SEPN1- or NEB-related myopathies. On biopsy, the Australian proband showed classical myosin storage myopathy features, while the UK patient showed multi-minicore like areas. To establish pathogenicity of the Arg1712Trp mutation, we expressed mutant MYH7 protein in COS-7 cells, observing abnormal mutant myosin aggregation compared to wild-type. We describe skinned myofiber studies of patient muscle and hypertrophy of type II myofibers, which may be a compensatory mechanism. In summary, we have expanded the phenotype of ultra-rare recessive MYH7 disease, and provide novel insights into associated changes in muscle physiology.
Collapse
|
2
|
Beecroft SJ, McLean CA, Delatycki MB, Koshy K, Yiu E, Haliloglu G, Orhan D, Lamont PJ, Davis MR, Laing NG, Ravenscroft G. Expanding the phenotypic spectrum associated with mutations of DYNC1H1. Neuromuscul Disord 2017; 27:607-615. [PMID: 28554554 DOI: 10.1016/j.nmd.2017.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022]
Abstract
Autosomal dominant mutations of DYNC1H1 cause a range of neurogenetic diseases, including mental retardation with cortical malformations, hereditary spastic paraplegia and spinal muscular atrophy. Using SNP array, linkage analysis and next generation sequencing, we identified two families and one isolated proband sharing a known spinal muscular atrophy, lower extremity predominant (SMALED) causing mutation DYNC1H1 c.1792C>T, p.Arg598Cys, and another family harbouring a c.2327C>T, p.Pro776Leu mutation. Here, we present a detailed clinical and pathological examination of these patients, and show that patients with DYNC1H1 mutations may present with a phenotype mimicking a congenital myopathy. We also highlight features that increase the phenotypic overlap with BICD2, which causes SMALED2. Serial muscle biopsies were available for several patients, spanning from infancy and early childhood to middle age. These provide a unique insight into the developmental and pathological origins of SMALED, suggesting in utero denervation with reinnervation by surrounding intact motor neurons and segmental anterior horn cell deficits. We characterise biopsy features that may make diagnosis of this condition easier in the future.
Collapse
Affiliation(s)
- Sarah J Beecroft
- Neurogenetic Diseases Group Centre for Medical Research, QEII Medical Centre, University of Western Australia, Nedlands, WA 6009, Australia; QEII Medical Centre, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Catriona A McLean
- Victorian Neuromuscular Laboratory, Alfred Health, Commercial Rd, Prahran, Vic. 3181, Australia
| | - Martin B Delatycki
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Vic. 3052, Australia; Victorian Clinical Genetics Services, Parkville, Vic. 3052, Australia
| | - Kurian Koshy
- Launceston General Hospital, Launceston, Tas. 7250, Australia
| | - Eppie Yiu
- Bruce Lefroy Centre, Murdoch Childrens Research Institute, Parkville, Vic. 3052, Australia; Neurology Department, Royal Children's Hospital, Melbourne, Vic. 3052, Australia
| | - Goknur Haliloglu
- Department of Pediatric Neurology, Hacettepe University Children's Hospital, Ankara 06100, Turkey
| | - Diclehan Orhan
- Pediatric Pathology Unit, Hacettepe University Children's Hospital, Ankara 06100, Turkey
| | - Phillipa J Lamont
- Neurogenetic Unit, Department of Neurology, Royal Perth Hospital, Australia
| | - Mark R Davis
- Neurogenetic Unit, Department of Diagnostic Genomics, PathWest, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Nigel G Laing
- Neurogenetic Diseases Group Centre for Medical Research, QEII Medical Centre, University of Western Australia, Nedlands, WA 6009, Australia; QEII Medical Centre, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia; Neurogenetic Unit, Department of Diagnostic Genomics, PathWest, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Gianina Ravenscroft
- Neurogenetic Diseases Group Centre for Medical Research, QEII Medical Centre, University of Western Australia, Nedlands, WA 6009, Australia; QEII Medical Centre, Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia.
| |
Collapse
|