Congenital polyneuropathy in Walker-Warburg syndrome.

Polyneuropathy was found in a patient with the Walker-Warburg syndrome. The most dominant features were the presence of extremely and tortuously proliferated myelin sheaths, the most of which having no neurofilaments and neurotubules. The other peculiar findings were the presence of microfilaments in Schwann cell cytoplasms, which were very similar to neurofilaments, and the presence of partial and abrupt disappearance of myelin sheaths. The severity of neuropathy was variable among nerve bundles, and a few nerve bundles looked normal on light microscopy. The above-mentioned lesions did not suggest the degeneration and/or regeneration of normally developed nerve fibers. We could not conclude the pathogenesis of this neuropathy, however, it was logical to consider that they reflected dysplastic myelination due to Schwann cell dysmaturity as well as the cerebral dysplasia.