Abstract: Objective To analyse the characteristics of symptoms, signs and electrophysiology in Charcot-Marie-Tooth disease (CMT) with peripheral myelin protein 22 (PMP22) gene duplication abnormality.Methods 61 patients with CMT, 14 patients with family history and 47 sporadic patients were included. PMP22 gene duplication fragment was detected with PCR-double enzyme cutting assay. Medical history, signs were collected. Some of them received lumbar puncture and sural nerve pathological examination. Results The main clinical manifestation of the patients with PMP22 gene duplication abnormlity were asthenia of both lower extremities, especially dorsiflexion of foot, accompanied with distal atrophy (especially bilateral legs), some with upper extremity distal atrophy, ankle hyporeflexia or vanished and sensory disturbance. Protein in cerebrospinal fluid may increase, giant potential and conduction velocity of sensory and motor nerve decreased. Sural nerve biopsies revealed demyelination accompanied with axonal degeneration.Conclusion The main clinical manifestation of patients with PMP22 gene duplication abnormlity is charactered as the distal atrophy and asthenia of lower limbs, accompanied with sensory abnormlity. Myelin sheath and axonal alteration were found in electromyogram and peripheral nerve pathology.

Key words: Charcot-Marie-Tooth disease (CMT), peripheral myelin protein 22 (PMP22) gene, duplication abnormality, clinical phenotype, pathology