Article
Two novel MYH7 proline substitutions cause Laing Distal Myopathy-like phenotypes with variable expressivity and neck extensor contracture. Public Deposited
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https://scholar.colorado.edu/concern/articles/1544bp88b
- Abstract
- BACKGROUND: Human skeletal muscles express three major myosin heavy chain (MyHC) isoforms: MyHCIIx (MYH1) in fast type 2B muscle fibers, MyHCIIa (MYH2) in fast type 2A fibers and MyHCI/β-cardiac MyHC (MYH7) in slow type I skeletal fibers and cardiac ventricles. In line with its expression pattern, MYH7 mutations have been reported in association with hypertrophic or dilated cardiomyopathy, skeletal myopathies or a combination of both. We analyzed the clinical and molecular phenotype of two unrelated families of Jewish Moroccan ancestry that presented with apparently autosomal dominant inheritance of progressive Laing-like distal myopathy with non-specific myopathic changes, but uncommon marked contractures and wasting of the neck extensors. METHODS: Clinical phenotyping, whole exome sequencing and restriction analysis, generation of mutants followed by cell culture transfection and imaging. RESULTS: Using whole exome sequencing we identified in both families two novel heterozygous proline substitutions located in exon 31 of MYH7 within its rod domain: c.4309G>C (p.Ala1437Pro) and c.4301G>C (p.Arg1434Pro). Here we show that the phenotype caused by these mutations includes marked cervical muscle contracture, and report that the severity of the phenotype varies significantly, to the extent of non-penetrance in one of the families. Finally, we provide evidence that both proline substitutions impair myosin self-assembly in non-muscle cells transfected with β-myosin constructs carrying the mutations, but do not prevent incorporation of the mutant molecules into the sarcomere. CONCLUSIONS: This study expands our clinical and molecular knowledge of MYH7 rod mutations causing skeletal myopathies, and underscores the importance of discussing disease penetrance during genetic counseling.
- Creator
- Date Issued
- 2016-08-12
- Academic Affiliation
- Journal Title
- Journal Issue/Number
- 1
- Journal Volume
- 17
- File Extent
- 57-57
- Subject
- Dernière modification
- 2019-12-05
- Identifier
- PubMed ID: 27519903
- Resource Type
- Déclaration de droits
- DOI
- ISSN
- 1471-2350
- Language
- License
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La vignette | Titre | Date de téléchargement | Visibilité | actes |
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twoNovelMyh7ProlineSubstitutionsCauseLaingDistalMyopathy.pdf | 2019-12-05 | Public | Télécharger |