Autosomal recessive distal muscular dystrophy: a comparative study with distal myopathy with rimmed vacuole formation.

To clarify the clinical and morphological characteristics of distal muscular dystrophy, clinical and pathological material from 4 affected persons was compared with similar studies in 4 patients with distal myopathy with rimmed vacuole formation. Although these two forms of autosomal recessive distal myopathy with onset in young adulthood were highly similar in their clinical symptoms, histochemical and electron microscopic findings of muscles subjected to biopsy were quite different. The muscle abnormalities in distal muscular dystrophy were almost the same as those in Duchenne muscular dystrophy, showing massive fiber necrosis followed by active fiber regeneration. In contrast, distal myopathy with rimmed vacuole formation showed a progressive muscle fiber atrophy and loss, rimmed vacuoles in the sarcoplasm, and no apparent fiber necrosis or regeneration.