Fetal alcohol myopathy.

A unique myopathic process in three flaccid, hypotonic, and weak neonates born to alcoholic mothers was investigated. In utero activity was depressed in all 3 cases. The muscle biopsies showed hypotrophy, dominance of type II fibers, and central nuclei. There was marked sarcomeric dysplasia at the ultrastructural level. Sarcomeres were of variable length and diameters; Z-band material with actin persisted in a coagulum of granulofilamentous debris; the number of myosin filaments was decreased. The degree to which myocytes were affected varied from focal to holocellular dysplasia. The disorder at the ultrastructural level in these damaged muscles from infants with the fetal alcohol syndrome is a unique constellation, warranting the term "fetal alcohol myopathy."