Familial myopathy with scapulohumeral distribution, rigid spine, cardiopathy and mitochondrial abnormality.

A 37-year-old woman with scapulohumeral muscular atrophy, rigid spine and cardiopathy is reported. Muscle weakness, advanced atrioventricular block and contractures at the neck, elbows and ankles had occurred during her childhood. An autosomal dominant mode of inheritance was suggested because her mother, sister and brother had the same disorder. Pleomorphic mitochondria had accumulated in the subsarcolemmal space of the skeletal muscle. There was no evident enzyme defect in the mitochondrial electron transport system. Although the clinical features had some similarity with those of Emery-Dreifuss muscular dystrophy or rigid spine syndrome, the pattern of inheritance and the muscle pathology differed.