NEFL and Charcot-Marie-Tooth disease: Lastly, we demonstrate for the first time that a clinically relevant biomarker, plasma NfL concentration, previously shown to be elevated in CMT patients including two cases with CMT4C, correlating with clinical severity (Sandelius et al., 2018), is also progressively elevated in Sh3tc2−/− mice and shows a significant improvement following gene replacement therapy.