A new familial congenital myopathy in children with desmin and dystrophin reacting plaques.

In 5 children with a progressive congenital myopathy representing 3 different families, unusual histological, immunohistochemical and ultrastructural changes in skeletal muscle have been found. Histologically, this myopathy was characterized by the presence of fine hyaline plaques devoid of oxidative as well as ATPase enzyme activities. At the ultrastructural level plaques were composed of helical filaments and amorphous dense material. Helical filament storage corresponded to strong desmin as well as ubiquitin immunoreactivity. In addition they were also dystrophin positive. The exclusive appearance of desmin, ubiquitin and dystrophin positive plaques in muscle specimens from 5 children emphasize the uniqueness of these plaques as well as this special form of a congenital myopathy.