Hereditary motor sensory neuropathies in childhood.

Clinical data on 24 patients with hereditary motor sensory neuropathies, with onset in the paediatric period, and of their relatives, is reported. Electrophysiological studies were done in all patients and in 15 relatives. The patients were divided into two groups (Types I and II) and their hereditary trait was determined. In 11 patients a sural nerve biopsy was performed and revealed different patterns of histological alterations. The nerve biopsy always confirmed the value of conduction velocity in distinguishing between Types I and II. A genetic discordance was observed, both in regard to the phenotype and the conduction velocity, and there was increased slowing of the conduction velocity as individuals grew older. Thus the classification of these disorders in childhood can be particularly difficult. The rôle of sural nerve biopsy is discussed.