DOMINANTLY INHERITED CYTOPLASMIC BODY MYOPATHY IN A JAPANESE KINDRED

An autosomal dominant progressive myopathy with diffuse cytoplasmic bo dies (CBs) is described. In four successive generations, 12 patients s uffered from weakness and atrophy of muscles in the distal extremities , neck, thorax and shoulder girdles. The mean age at onset was 42 year s old, and the patients became disabled after 5 to 10 years due to chr onic respiratory failure. The level of serum creatine kinase was norma l or slightly elevated. An electromyogram showed a predominant myopath ic change with a slight neurogenic change. Autopsy of 2 cases revealed numerous CBs in the skeletal muscles. Smooth and cardiac muscles were also affected. CBs were present predominantly in type I fibers in ske letal muscles. Males were more frequently affected than females (2:1). An electron microscopic examination showed dense central cores of myo filaments surrounded by radiating filaments. Characteristics of clinic al course and histopathological findings in a new kindred are discusse d in this rare disease.