Electrophysiological characterization of Charcot–Marie–Tooth disease type 1A in Taiwan

Background: Charcot–Marie–Tooth disease type 1A (CMT1A) is the most common type of hereditary neuropathy. The demyelinating pathology of CMT1A results in significant nerve conduction slowing such that a nerve conduction study (NCS) is important in the clinical assessment of CMT1A. In this study, we analyzed and reported the electrophysiological features of a large Taiwanese cohort with CMT1A. Methods: We retrospectively analyzed the NCS data of 106 Taiwanese patients with CMT1A. We also compared the electrophysiological parameters of the CMT1A patients with those of 20 patients with early-onset Charcot–Marie–Tooth disease type 1B (CMT1B). Results: The patients with CMT1A had a significant but variable degree of slowed nerve conduction. The median motor nerve conduction velocities (MNCVs) varied from 10.0 to 37.3 m/s in the entire CMT1A cohort but were more concordant in patients within a family (p<0.001). In each patient, the MNCVs among different nerves were concordant (p<0.001), and the MNCVs tended to remain steady longitudinally. Moreover, younger patients had a slower MNCV than older patients within the CMT1A population (p<0.001). The average median MNCV was significantly faster in the CMT1A patients than in the CMT1B patients (21.8±6.2 m/s and 16.3±3.6 m/s; p