Congenital myopathies.

The congenital myopathies (CM) are a group of non or little progressive neuromuscular conditions, often hereditary, delineated by morphological techniques, ie, enzyme histochemistry and electron microscopy. The catalogue of CM entailing well known "classic" conditions as central core disease, nemaline myopathy, and centronuclear myopathy has continuously been expanded, now comprising some 40 conditions. Nosologic advances have occurred with immunohistochemical techniques that show generalized or focal protein abnormalities within muscle fibers of certain CM, but at much slower pace as to localization of CM genes. So far, only those for central core disease, nemaline myopathy, and myotubular myopathy have been reported. Epidemiological rarity and nosographic controversy of CM have contributed to this lack of molecular genetic progress in CM.