Becker's X-linked muscular dystrophy histological, enzyme-histochemical, and ultrastructural studies of two cases, originally reported by Becker

Summary

Muscle biopsies of two patients originally reported in the Göttingen family by Becker (1962) that formed the basis of separating a benign X-linked muscular dystrophy from the rapidly progressive Duchenne-type X-linked muscular dystrophy, revealed mild pathological changes in the younger patient and more advanced in the older one, consisting of increased spectra of fiber diameters, endomysial fibrosis, angulated fibers, pyknotic nuclear clumps and small groups of atrophic fibers. Essentially, both biopsies showed the same changes, but of different severity, possibly due to the differences in age and muscle biopsy sites. These changes were regarded “myopathic”, but a neurogenic component was suggested. Our observations accord well with those of a larger series (Bradley et al., 1978) where both electromyography and histopathology revealed a mixed “myopathic-neurogenic pattern” in patients with Becker-type dystrophy. Differential diagnostic aspects encompass Duchenne's muscular dystrophy, the other hereditary dystrophies and X-linked proximal spinal muscular atrophies. The precise nature of Becker-type muscular dystrophy requires morphological data on peripheral nerves, spinal roots and spinal cord anterior horn cells as well as sequential biopsy analysis to substantiate the primary site of pathology. However, on the basis of available data, it seems reasonable to suggest that the early changes of degeneration/regeneration which are accompanied by a markedly elevated CPK eventuate in the histopathologic and electromyographic patterns illustrated in these two patients with Beckertype dystrophy.