Congenital Myopathies and their Pathogeneses

Abstract

Pathological changes of a few congenital myopathies were studied together with observations of various experimental muscular changes in animal. Pathological abnormalities of these disorders *were different in nature from those of other ordinary myopathies in that in these conditions selective type atrophy or partial structural changes within the fibers are the chief findings while in other myopathies break down of entire structure of individual fibers is indipensable change. Type I fiber atrophy was recognized in 3 cases of congenital muscular dystrophy, in each one case of myotubular myopathy and of nemaline myopathy. In nemaline myopathy, numerous nemaline bodies 2 were seen in atrophied type I fibers on a occasion, but on the other occasiona, typical neurogenic pathological picture with small groups of small fibers was observed. Central nuclei and centrally limited structural changes were characteristics of myotublar myopathy, but they were also seen, though not very frequent, in 6 cases of congenital muscular dystrophy. In myotublar myopathy, the central area of abnormal structure was varied in size, shape and in nature from to case to case. *Probably, this central variation represents various phases of a single disease process. The specific structural changes such as nemaline bodies or myotube-like structures are possibly not constant or permanent features but profiles of individual phases of certain processes.
As a conclusion, it was postulated that neurogenic factors have more important role in the pathogeneses of congenital myopathies these disorders than in those of other myopathies.