Correlation between clinical and electrophysiological characteristics in 59 patients with Charcot-Marie-Tooth disease type 1X

Abstract

Objective To analyze the relationship between gender, age at onset, duration, disabilities progress and indexes of peripheral nerve electrophysiology in Charcot-Marie-Tooth disease type 1X(CMT1X) patients. Methods To analyze 59 CMT1X patients of Chinese Han origin with detected connexin 32(CX32) gene mutations using clinical and electrophysiological assessment, including the Charcot-Marie-Tooth Neuropathy Score (CMTNS), Overall Neuropathy Limitation Scale (ONLS) and Functional Disability Scale(FDS). Statistical method was used to analyze the relationship between gender, age at onset, duration, disabilities progress and indexes of peripheral nerve electrophysiology. Results The male CMT1X patients were more severely affected than female patients. Motor nerve conduction velocity (MNCV), compound muscle action potential (CMAP) amplitude and sensory nerve conduction velocity (SNCV) of median nerve of male patients(（34.5±6.3）, (36.2±5.5) m/s, (2.7±1.9) mV) were lower than those of female patients((43.5±7.2), (44.3±7.4) m/s, t=-5.002, -4.022，both P<0.01；（4.2±2.9） mV，t=-2.177，P<0.05), and sensory nerve action potential (SNAP) amplitude have no significant difference than female patients. Age of male(r=-0.451，P<0.01) and female(r=-0.427，P<0.05) patients in CMT1X were significantly related with their median nerve CMAP amplitude and have no correlation with MNCV, male and female respectively. The clinical disability progress was significantly related with age, disease duration and CMAP amplitude in male CMT1X patients, but was not related to MNCV, SNCV, SNAP and age at onset. The CMTNS of male and female patients increased with age of 0.29 points/year(r=0.600, P<0.01) and 0.18 points/year (r=0.420, P<0.05) respectively and were correlated with two scale, FDS(r=0.901, P<0.01) and ONLS(r=0.904, P<0.01). Conclusions The clinical disability progress is significantly related with age, disease duration and CMAP amplitude. CMTNS is suitable to evaluate and forecast the clinical disabilities of CMT1X patients dynamically, and is significantly related with FDS and ONLS. Key words: Charcot-Marie-Tooth disease; Connexins; Electrophysiology