Oculopharyngeal muscular dystrophy and distal myopathy. Intrafamilial difference in the onset and distribution of muscular involvement.

A family is reported which included a patient with a variant form of oculopharyngeal muscular dystrophy. The patient's son suffered from infantile muscular dystrophy with a distal distribution in the lower extremities and no oculopharyngeal symptoms. Case 1, the father, showed blepharoptosis, but no limitation of ocular movements. Case 2, the son, showed early onset of weakness and more rapid progression of muscle involvement than the father. In both patients EMG, muscle biopsies and elevated serum CPK indicated the myopathic nature of the disorder. A muscle biopsy specimen in Case 2 showed abundant rimmed vacuoles and abnormal filaments 13-19 nm in diameter in the sarcoplasm, usually reported to occur in inclusion body myositis. The findings indicate that oculopharyngeal muscular dystrophy and distal myopathy are related in their etiology and distal myopathy and inclusion body myositis are regarded as variant forms of the same disease.