Longitudinal 16‐year study of dominant intermediate CMT type C neuropathy

Background Dominant‐intermediate Charcot–Marie‐Tooth neuropathy subtype C (DI‐CMTC) is associated with mutations in the YARS gene. The aim of this study is to investigate the long‐term natural history of the disease. Methods In a 5‐generation DI‐CMTC family, we compared data from 2016 to that of 2000 in 13 of 21 original participants. Results Five women and 8 men were examined. While most symptoms and signs progressed, only gait progression was statistically significant ( P = .016). The median CMT Neuropathy Score was 6.08 in 2000 and 11 in 2016 ( P = .001). Quality of life (QOL) deteriorated in mobility ( P = .008), pain/discomfort ( P = .011), and anxiety/depression ( P = .014). Median and ulnar compound muscle action potential amplitudes decreased from 9.35 ± 2.90 mV to 6.0 ± 2.9 mV ( P = .002), and from 9.24 ± 2.10 mV to 6.06 ± 1.81 mV ( P = .004), respectively, whereas motor nerve conduction velocities remained unchanged. Conclusions DI‐CMTC in this family is a slowly progressive disease with axonal degeneration, deteriorating mobility and QOL.