RESUMO
Objective To study the clinical, neuro-electrophysiology features of Charcot-Marie-Tooth disease type 1A (CMT1A) and its gene mutation analysis.Methods 9 members of the family with CMT1A underwent detailed clinical examinations and gene mutation analysis was carried out in 7 of them. The probands accepted electromyography and nerve, muscle biopsy.Results Five patients of the family were attacked and consistent with autosomal dominant inheritance type. Except one asymptomatic patient, age at onset was in the first or second decade. The clinical features were slowly progressive distal muscle weakness, atrophy and end-brush form sensory decrement, diminished or absent tendon reflexes, foot deformity(pes cavus).The probands showed highly decreased sensory and motor conduction velocities. Gene mutation analysis showed large fragment tandem duplication containing peripheral myelin protein 22(PMP22) gene in all four patients out of the seven family members who attended the gene diagnosis.Conclusion CMT1A is the most common form of CMT. The disease usually begins in childhood or adolescence. Clinical featurs include progressive distal muscle weekness and atrophy, diminished or absent tendon reflexes. The motor nerve conduction velocity is slowed below the limit of 38 m/s. Tandem duplication on chromosome 17p11.2, encompassing the PMP22 gene is the main mutation type of CMT1A.