Familial fingerprint body myopathy.

Muscle biopsy specimens from two half brothers with a congenital benign muscle disorder and from their mother, clinically unaffected, were studied by histochemistry and electron microscopy. In the children's biopsy specimens, the ultrastructural examination showed numerous fingerprint bodies located at the periphery of the muscle fibers. The histochemical pattern was different in these two specimens. In the mother's biopsy specimen, while fingerprint bodies were not found, the muscle fibers showed slight but definite changes. Even if the fingerprint bodies by themselves are not specific for a particular muscle disease, their occurrence in two half brothers is a valid argument in favor of the individalization of the fingerprint body myopathy, which has been previously described.