Muscle plasma membrane abnormalities in infants with Duchenne muscular dystrophy

Muscle biopsies from one preclinical case, one early case, four symptomatic cases of Duchenne muscular dystrophy, and six controls were investigated for the presence of delta lesions by phase optics and conventional electronmicroscopy. By phase microscopy the frequency of delta lesions was 4.9% in the preclinical and early cases and 4.0% in the four symptomatic cases. The incidence of delta lesions in the controls was 0.4%. Electronmicroscopic studies of delta lesions revealed similar findings in the preclinical, early, and symptomatic cases. The common denominator of the delta lesions was disruption of the muscle plasma membrane. Plasma membrane lesions occur early in Duchenne muscular dystrophy.