Abstract
A case is reported of a boy who developed a severe polyneuropathy in early infancy and died of respiratory failure at the age of 18 months. Autopsy revealed almost total lack of myelin sheaths in the cranial, spinal and peripheral nerves. The defect involved the entire peripheral nervous system and was confined to it, central myelination being normal. It is suggested that this case is another example of the condition described by Lyon (1969) and by Kennedy et al. (1971) in which pathological observations were confined to biopsy material. In spite of some similarities between these cases and those of hypertrophic neuropathy reported by Déjerine and Sottas in 1893, they seem to form a distinct sub-group, possibly even a separate entity: infantile polyneuropathy with defective myelination.