TABLE 1.
Phenotype of missense variants causing X‐linked Charcot‐Marie‐Tooth disease, stratified by structural domain of connexin 32.
| Intracellular | Transmembrane | Extracellular | p value | |
|---|---|---|---|---|
| Patients, % (n) | 27 (64) | 31 (72) | 41 (94) | |
| Families, % (n) | 31 (42) | 35 (47) | 34 (45) | |
| Variants, % (n) | 30 (22) | 34 (25) | 36 (26) | |
| Male/Female | 30/34 | 35/37 | 41/53 | |
| Age at the evaluation, years | 46 | 48 | 44 | |
| CMTES, mean (±SD) | 7.1 (±0.6) | 10.5 (±0.5) | 8.7 (±0.5) | <0.000 1 (44) |
| ONLS, mean (±SD) | 2.3 (±0.2) | 3.6 (±0.2] | 2.4 (±0.2) | <0.000 1 (44) |
| Age of onset, mean (±SD) years | 22 (±1.8) | 13 (±1.1) | 20 (±1.4) | <0.000 1 (44) |
| Walking aids (cane or walker), % (n) | 11 (7) | 17 (12) | 16 (12) | |
| Orthosis, % (n) | 47 (30) | 60 (43) | 41 (31) | 0.045 |
| Orthopedic surgery of the lower limbs, % (n) | 16 (10) | 17 (12) | 16 (12) | |
| Treatment for neuropathic pain, % (n) | 15 (9) | 24 (16) | 17 (12) | |
| MNVC median nerve, mean (±SD) m/s | 42 (±1.4) | 37 (±1.2) | 38 (±1.4) | 0.017 1 (44) |
| MNCV ulnar nerve, mean (±SD) m/s | 46 (±1.4) | 40 (±1.4) | 43 (±1.4) | 0.025 1 (44) |
| Sum of the CMAPs of the median and ulnar nerves (±SD) mV | 13.1 (±1.2) | 8.1 (±0.9) | 12.0 (±0.9) | 0.002 1 (44) |
| Motor conduction block ≥30% and/or temporal dispersion, % (n) | 50 (18) | 48 (16) | 29 (13) | |
| Distal latency >4 ms, % (n) | 61 (20) | 75 (24) | 53 (23) | 0.037 |
1
Wilcoxon rank sum test, Pearson’s chi‐squared test or Fisher’sexact test, dedending on the type of variable studied.
Abbreviations: CMAP, compound muscle action potential; CMTES, Charcot‐Marie‐Tooth Examination Score version 2; MNCV, motor nerve conduction velocity; ONLS, Overall Neuropathy Limitation Score; SD, standard deviation.