[A case of hereditary motor and sensory neuropathy of neuronal type with retardation of motor development].

An atypical case of hereditary motor and sensory neuropathy of neuronal type with retardation of motor development was described. The patient was a 15-year-old boy who had suffered from distal muscle weakness with atrophy of four limbs and deformities of hands and feet since age 6 months. These symptoms were slowly progressive. He had never walked. His parents were not consanguinous. His parents and two siblings were unremarkable on neurological examination and on nerve conduction studies. On neurological examination, he showed severe degree of muscle weakness and atrophy in the distal upper and lower limbs, moderate degree of muscle weakness and atrophy in the proximal upper limbs and slight degree of made weakness and atrophy in the proximal upper limbs. Deep tendon reflexes in four limbs were decreased or absent. Vibration sensation was moderately decreased in the distal parts of four limbs. On the nerve conduction studies, no sensory nerve potential was recorded in the median, ulnar and sural nerves bilaterally. Motor nerve conduction velocity of the right tibial nerve was 21 m/sec and the amplitude of the compound muscle action potential (M-wave) was 0.15 mV, and no M-wave was elicited with the electrical stimulation of the median, ulnar and peroneal nerves. Neelde EMG showed fibrillation potentials and giant spikes with a reduction of the number of motor units. On sural nerve biopsy, the densities of both myelinated and unmyelinated fibers were severely decreased.(ABSTRACT TRUNCATED AT 250 WORDS)