Muscle histochemistry in congenital muscular dystrophy with central nervous system involvement.

Muscles from 13 patients with clinical characteristics of congenital muscular dystrophy and central nervous system involvement (Fukuyama type) (FCMD) were examined using morphometric and fiber type analysis. The muscles from patients aged 5 months to 3 years demonstrated small-calibered fibers with increased variation in fiber size, connective tissue proliferation, and scattered necrotic and regenerating fibers. Groups of atrophic fibers were absent. Both type 1 and type 2 fibers were affected, though type 1 fibers predominated and type 2B fibers decreased as the disease progressed. The muscle changes were apparently progressive, affecting not only the limbs but also the intercostal, diaphragm, and cardiac muscles. Although there was no qualitative difference in the muscle histochemistry between FCMD and Duchenne muscular dystrophy (DMD), there was a greater proportion of type 2C fibers and fibrosis was present at the early infantile stage of FCMD.