[Fiber type disproportion, a subtype of so-called nonprogressive myopathies (author's transl)].

The clinical course, serological, and electromyographic findings, and also histological, histochemical, and electron microscopic abnormalities of two patients with congenital fiber type disproportion, a subtype of the so-called congenital nonprogressive myopathies, are described in this study. Other important subgroups are discussed regarding both variation and overlapping. As these diseases neither belong to the "classical" myopathies nor to the neuropathies, other possible factors such as a distrubed trophic function of the nerve or abnormalities of the reflex arc are under consideration.