Nemaline myopathy and a mitochondrial neuromuscular disorder in one family.
A family composed of parents and four children is reported. Two brothers presented from early infancy with hypotonia and non-progressive weakness. Muscle biopsy in both revealed numerous typical nemaline rods. The father, suffering from backache, had a slow MNCV of both common peroneal nerves. His muscle revealed variation in fiber size, splitting, type 1 atrophy and numerous pleomorphic mitochondria with crystalline inclusions. The mother's muscle showed type 2 atrophy, foci of myofibrillar degeneration, and lipofuscin bodies. In a 12-year-old daughter and a 5-year-old son the muscle revealed an excess of small, bizarre mitochondria and lipid droplets. The coexistence of nemaline myopathy and a mitochondrial neuromuscular disorder in one family has never been reported in the literature. It might be a coincidence of two rare muscle disorders in one family, or it might be the polymorphic expression of a single etiological factor causing a defect in protein synthesis.
D000328:Adult; D001707:Biopsy, Needle; D002648:Child; D002675:Child, Preschool; D006801:Humans; D002479:Inclusion Bodies / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008931:Mitochondria, Muscle / Q000648:ultrastructure*; D009123:Muscle Hypotonia / Q000235:genetics / Q000473:pathology; D009132:Muscles / Q000473:pathology; D009133:Muscular Atrophy / Q000235:genetics / Q000473:pathology; D009468:Neuromuscular Diseases / Q000235:genetics* / Q000473:pathology