Clinical and genetic analysis of 2 families with Charcot-Marie-Tooth disease
Objective To investigate the clinical characteristics of Charcot-Marie-Tooth disease(CMT),and conduct genetic analysis.Methods The clinical data of 2 families were retrospectively analyzed.Results The proband of family 1 had atrophy of bilateral thigh and calf muscles,serum creatine kinase(CK)was 292 U/L,and EMG examination showed peripheral nerve damage of upper and lower limbs(mainly axonal).Genetic testing revealed that the proband carried a heterozygous mutation of NEFH:NM_02107:c.3057dupG:p.K1020Efs*43.According to American College of Medical Genetics and Genomics(ACMG),the variant of NEFH gene was interpreted as likely pathogenic(PS3_moderate+PM2+PM4+PP1).The proband of family 2 had scoliosis,calf muscle atrophy,flat foot,blood creatine kinase 80 U/L,and EMG examination showed peripheral nerve damage in the upper and lower limbs(mainly axonal).Genetic testing revealed that the proband carried a heterozygous mutation of the MFN2:NM_014874:c.746C>G:p.S249C.This mutation had not been reported and included in the relevant literature,and was likely to be pathogenic according to the ACMG regulation rating(Likely Pathogenic:PM1+PM2+PM5+PP3).Conclusions The clinical manifestations of the two families are muscle weakness with muscle atrophy,normal or mild elevation of creatine kinase,disappearance of tendon reflex,arched foot,and electromyography indicating neurogenic damage.Gene testing reveals that the probands carried heterozygous mutations in the NEFH and MFN2 genes,respectively.