Mitochondrial abnormalities in oculopharyngeal muscular dystrophy.

A family with oculopharyngeal muscular dystrophy (OPMD) is described. Histological and histochemical studies of muscle biopsy showed nonspecific myopathic changes; no "ragged-red" fibers were seen. Electron microscopy demonstrated bizarre large mitochondria with abnormal cristae, but no intranuclear inclusion bodies. Our findings are compatible with the possibility that OPMD is a heterogeneous syndrome, and may be a manifestation of mitochondrial myopathy.