Congenital muscular dystrophy. A histochemical study with morphometric analysis on biopsied muscles.

Muscle biopsies from 10 Japanese patients (9 females and 1 male) with congenital muscular dystrophy (CMD) were studied. Their clinical features varied remarkably in severity; one patient died at 6 years of age. Family history was negative in all but one patient who had an affected sibling. Muscle biopsy findings varied from mild myopathic to advanced dystrophic changes. Hypertrophic fibers associated with occasional fiber splitting were assumed to reflect a chronic dystrophic process. Histochemical examination revealed type 1 fiber predominance in 5 patients, and type 2 fiber predominance in one. Eight patients had a slight to moderate increase in the number of undifferentiated type 2C fibers suggesting a regenerating process after fiber necrosis. Type 2B fibers were fairly well preserved in 8 patients. The overall findings differed from those of the Fukuyama type congenital muscular dystrophy (FCMD) and Duchenne muscular dystrophy (DMD) in which more active fiber necrosis and regeneration are seen. We conclude that the present CMD patients suffered from a chronic dystrophic process similar to that in limb-girdle muscular dystrophy.