Hereditary motor and sensory neuropathy of neuronal type with onset in early childhood.

Eleven cases of a severe neuropathy with onset in early childhood are described. The condition commences with distal weakness and wasting of the lower limbs and subsequently involves the hands, causing severe paralysis of the hands and feet towards the end of the second decade. Sensory changes are common but are usually only mild. The peripheral nerves are not enlarged. Claw hand, scoliosis and other orthopaedic deformities are seen in the later stages. CSF protein is not elevated and there is only mild slowing of motor conduction velocities. The pathological changes in sural nerve biopsies are those of axonal degeneration affecting myelinated and unmyelinated fibres. Family studies suggested autosomal recessive inheritance in two kindreds and dominant inheritance in another. Five cases were sporadic. The condition is clinically more severe and of earlier onset than hereditary motor and sensory neuropathy (HMSN) type II and differs electrophysiologically and pathologically from Déjerine-Sottas disease.