Table 1.

Clinical characteristics of patients

ID	Mutations	Age at onset	Age at most recent exam, y	Presenting symptom	Motor exam Strength MRC scale 0–5a	Sensory exam	Additional findings	CMTNS-2 scoreb	Laboratory tests	Cardiac	EMG/NCS
1	E140K, P169T	Infancy	9	Toe walked at 15 months	Deltoids 2, biceps 3, triceps 4, wrist extensors/flexors 2, FDI/APB 2, ADM 0, iliopsoas 4, quadriceps 2, hamstrings 4, TA, gastrocne mius, foot eversion/inversion, great toe plantar/dorsiflexion 0	Decreased vibration at toes	Ptosis, facial weakness, facial fasciculation, dysarthria	17/28	Lactate 3.5 mmol/l (0.7–2.1), pyruvate 0.174 mmol/l, ratio: 20:1	Normal ECG and echo	Ulnar CMAP: 0.3 mV
									Cu 128 μg/dl (70–140) ceruloplasmin 26 mg/ml (16–66)		Ulnar motor CV: 44 m/s
2	R171Q, N135F	12	26	Foot drop, inability to keep up with peers	TA, gastrocnemius, foot eversion/inversion, great toe plantar/dorsiflexion 0	Decreased vibration at toes		7/28	Lactate 1.47 mmol/l, pyruvate 0.071 mmol/l, ratio:19.7	Frequent PVCs on 24-h holter monitoring (30%) Normal echocardiogram and stress ECG Referred to electrophysiology	Tibial motor response absent, peroneal motor response recorded from TA 0.32 mV, CV 43 m/s (across the knee) Radial and sural sensory re sponses absent. Ulnar SNAP 0.002 mV, CV 54 m/s. High amplitude, reduced re cruitment and polyphasic motor unit potentials in TA and FDI
					Otherwise normal strength				Cu 92 μg/dl, ceruloplasmin 23 mg/dl

^aMRC medical research council scale for muscle strength.

^bCMT Neuropathy Score (CMTNS) version 2 (CMTNSv2) score was calculated using a modified CMTNS that had been validated previously as a measure of disability due to CMT.

ADM = abductor digiti minimi; APB = abductor pollicis brevis; CMAP = compound muscle action potential; CV = conduction velocity; FDI = first dorsal interosseous; NCS = nerve conduction study; PVC = premature ventricular contractures; TA = tibialis anterior.