Sarcolemmal defect and subsarcolemmal lesion in a patient with gamma-sarcoglycan deficiency.

We report a case of gamma-sarcoglycanopathy with sarcolemmal defects and subsarcolemmal lesions indistinguishable from those in Duchenne muscular dystrophy. Both disorders share certain ultrastructure features that suggest a common pathogenesis related to primary deficiency of transmembrane glycoproteins (e.g., sarcoglycans) or deficiency in dystrophin, which produces a secondary deficiency in sarcoglycans. The lack of transmembrane glycoproteins may contribute to membrane lesions and associated muscle fiber degeneration and necrosis.