| 1. |
- Tajsharghi, Homa, et al.
(författare)
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Congenital myopathy with nemaline rods and cap structures caused by a mutation in the beta-tropomyosin gene (TPM2)
- 2007
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Ingår i: Archives of Neurology. - : American Medical Association. - 0003-9942 .- 1538-3687. ; 64:9, s. 1334-8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To describe the clinical, morphologic, and genetic findings in a family in which one woman had nemaline myopathy, whereas her daughter showed features of cap disease.PATIENTS: A 66-year-old woman and her 35-year-old daughter had congenital, slowly progressive muscle weakness. They had weakness in both proximal and distal muscles and facial diplegia with bilateral ptosis, a long narrow face, a high arched palate, and micrognathia.RESULTS: Muscle biopsy specimens in the mother at age 57 years had shown nemaline myopathy, whereas a biopsy specimen at age 32 years had demonstrated no rods. Muscle biopsy specimens in the daughter at age 26 years had shown features of cap disease and no apparent nemaline rods. A missense mutation, Glu41Lys, in the beta-tropomyosin gene TPM2 was identified in both patients but was absent in their healthy relatives.CONCLUSIONS: The results indicate that mutations in TPM2 may cause nemaline myopathy as well as cap disease with a dominant mode of inheritance. These disorders may thus be phenotypic variants of the same genetic defect.
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| 2. |
- Tajsharghi, Homa, 1968, et al.
(författare)
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Embryonic myosin heavy-chain mutations cause distal arthrogryposis and developmental myosin myopathy that persists postnatally.
- 2008
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Ingår i: Archives of neurology. - : American Medical Association (AMA). - 1538-3687 .- 0003-9942. ; 65:8, s. 1083-90
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Myosin is a molecular motor and the essential part of the thick filament of striated muscle. The expression of myosin heavy-chain (MyHC) isoforms is developmentally regulated. The embryonic isoform encoded from MYH3 (OMIM *160720) is expressed during fetal life. Recently, mutations in MYH3 were demonstrated to be associated with congenital joint contractures, that is, Freeman-Sheldon and Sheldon-Hall syndromes, which are both distal arthrogryposis syndromes. Mutations in other MyHC isoforms cause myopathy. It is unknown whether MYH3 mutations cause myopathy because muscle tissue has not been studied. OBJECTIVES: To determine whether novel MYH3 mutations are associated with distal arthrogryposis and to demonstrate myopathic changes in muscle biopsy specimens from 4 patients with distal arthrogryposis and MYH3 mutations. DESIGN: In a cohort of patients with distal arthrogryposis, we analyzed the entire coding sequence of MYH3. Muscle biopsy specimens were obtained, and in addition to morphologic analysis, the expression of MyHC isoforms was investigated at the protein and transcript levels. RESULTS: We identified patients from 3 families with novel MYH3 mutations. These mutations affect developmentally conserved residues that are located in different regions of the adenosine triphosphate-binding pocket of the MyHC head. The embryonic (MYH3) isoform was not detected in any of the muscle biopsy samples, indicating a normal developmental downregulation of MYH3 in these patients. However, morphologic analysis of muscle biopsy specimens from the 4 patients revealed mild and variable myopathic features and a pathologic upregulation of the fetal MyHC isoform (MYH8) in 1 patient. CONCLUSIONS: Distal arthrogryposis associated with MYH3 mutations is secondary to myosin myopathy, and postnatal muscle manifestations are variable.
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