Centronuclear myopathy: extraocular- and limb-muscle findings in an adult

Myotube-like structures were seen in extraocular and limb muscles in an adult with centronuclear myopathy. The limb-muscle fibers were very small and were of a uniform histochemical type. Extrajunctional acetylcholine receptors were not seen with immunoperoxidase stains, and ultrastructurally normal neuromuscular junctions were seen in the extraocular-muscle samples. Further studies on developing muscle are needed to identify possible mechanisms of arrest of muscle maturation.