Congenital muscle fiber-type disproportion in Krabbe's leukodystrophy.

Progressive spasticity, blindness, loss of skills, and neuropathy developed in a 4.5-month-old boy. When examined at 13 months, galactocerebrosidase and galactosylceramide-beta-galactosidase activities were deficient in leukocytes. Intramuscular nerves and a sural nerve biopsy specimen showed loss of nerve fibers, interstitial fibrosis, and axonal degeneration, rather than the segmental demyelination that predominates in most cases. A muscle biopsy specimen showed congenital muscle fiber-type disproportion (CMFTD). This case confirms a previous report of CMFTD in Krabbe's disease and supports a neurogenic mechanism as the basis for CMFTD.