Clinical, Electrophysiological And Molecular Genetic Characteristics Of59Chinese Han Patients With CMT1X

Objective To studied59chinese han Charcot-Marie-Tooth type1X(CMT1X) patients, discussed the china CMT1X patient’s clinical phenotype, electrophysiologic and the relationship of both.Background CMT1X is caused by mutation of gap junction beta1(GJB1) gene, the gene located on the X chromosome, which encodes the gap junction protein connexin32(Cx32).Part of studies found that the CMT1X patient clinical disabilities increases are significantly correlated with the motor nerve conduction velocity(MNCV), compound muscle action potential(CMAP), while others have suggested clinical disabilities progress of these patients were related to age, disease duration and CMAP, but not the MNCV. In the CMT1X patient, the feature of clinical and electrophysiologic have different reported between male and female, whether the feature of clinical and electrophysiologic are correlated with the different location and type of CX32mutation pot have different reported. In our research, we collected the china CMT1X patient’s date of clinical phenotype, genetics and electrophysiologic, investigated the relationship of them and feature of clinical and electrophysiologic.Methods To analyzed59Chinese han CMT1X patients origin with mutations in CX32gene using clinical and electrophysiological ssessment, including the Charcot-Marie-Tooth neuropathy score(CMTNS), overall neuropathy limitation scale(ONLS) and functional disability scale(FDS).Result Males were more severely affected than females in the CMT1X, which MNCV and CMAP lower than females. This situation presumably caused by the lyonization of CX32. The CMTNS of male (2.9points/decade; r=0.60, p<0.001) and female (1.75points/decade; r=0.42, p<0.05) respectively increased with age. Patients’clinical disabilities progress significantly related with age, disease duration and CMAP, but not MNCV. The different location of CX32missense mutations has the same impact on the clinical expression and CMAP. The CX32missense mutations within the region of the first and second transmembrane or Intracellular loop have the lower MNCV than the other CX32domain.Conclusion CMTNS is suit to dynamic evaluation and forecast the clinical disabilities of Chinese han CMTIX patients, and well related with FDS and ONLS. The CMT1X patients’clinical disabilities significantly increasing with age, disease duration and CMAP reduce, supported that the cause of CMT1X is dependent axonal degeneration and loss. These degree of change in CMAP amplitude as a sign of axonal degenerated is useful for predicting the clinical severity of the disease. The CMT1X patients with distinct CX32missense mutation have the similar degree of clinical disabilities and CMAP.