Table 1.
Clinical features in four affected members with neurophysiologic characteristics of family 1 and family 2’s probands
| Family 2 with GJB1 c.G224C:p.R75P variant | Family 1 with BSCL2 c.C269T:p.S90L mutation | Characteristics | ||
|---|---|---|---|---|
| proband IV-4 | proband III-2 | III-15 | III-1 | Patients |
| Male | Male | Male | Male | Gender |
| 21 | 7 | 7 | 10 | Age at onset (year) |
| 22 | 19 | 14 | 12 | Age at the first visit (year) |
| CMT | CMT | CMT | CMT | Clinical diagnosis |
| walking difficulty | Unsteady gait frequent falls |
Unsteady gait frequent falls |
Unsteady gait toe walking frequent falls |
Presenting symptom |
| Steppage gait | Steppage gait with mild spastic feature |
Steppage gait | Steppage gait | Gait |
| Absent tendon reflexes in both upper and lower extremities, absent tendon reflexes with weakness of foot dorsiflexion at the ankle |
UL: + LL: +++ |
UL: ++ LL: ++ |
UL: ++ LL: +++ |
DTR |
| Weakness of the feet and ankles, symmetrical atrophy of muscles below the knee (stork leg appearance), atrophy of intrinsic hand muscles, predominantly thenar |
Distal> proximal both UL&LL asymmetric calf atrophy thenar atrophy |
Distal = proximal both UL&LL pretibial atrophy |
Distal> proximal both UL&LL thenar atrophy pretibial atrophy |
Muscular atrophy and weakness |
| Bilateral foot drop, pes cavus, hammer toe | Pes cavus hammer toe |
Bilateral foot drop pes cavus |
Foot drop pes cavus |
Foot deformity |
| Equinovarus, arthralgia, mild to moderate sensory deficits of position, vibration and pain in the feet, claw hands |
LL hyperreflexia scoliosis, equinovarus, dermatographism, reduced gag reflex |
Double Babinski sign stridor, previous tendon release of achilles, scoliosis, equinovarus |
LL hyperreflexia claw hands, delayed wound healing, equinovarus, scoliosis |
Additional features |
| Absent | 5.9 | NT | NT | Median CMAP (mV) |
| Absent | 54.4 | NT | NT | Median MNCV (m/s) |
| Absent | 4.4 | NT | NT | Median SNAP (µV) |
| Absent | 34.6 | NT | NT | Median SNCV (m/s) |
| 2.25 (mV)(normal: 6 mV) | 2.6 | NT | NT | Ulnar CMAP (mV) |
| 20 (m/s) (normal: 50 m/s) | 49.8 | NT | NT | Ulnar MNCV(m/s) |
| Absent | 4.3 | NT | NT | Ulnar SNAP (µV) |
| Absent | 28.1 | NT | NT | Ulnar SNCV (m/s) |
| Absent | 0.253 | NT | NT | Tibial CMAP (mV) |
| Absent | 37 | NT | NT | Tibial MNCV (m/s) |
| Absent | Absent | NT | NT | Peroneal CMAP (mV) |
| NT | Absent | NT | NT | Sural SNAP (µV) |
| Absent | NT | NT | NT | Radial SNAP (µV) |
CMT: Charcot-Marie-Tooth disease; +: hyporeflexia; ++: normal; +++: hyperreflexia; UL: upper limb; LL: lower limb; MNCV: motor nerve conduction velocity; CMAP: compound muscle action potential; SNCV: sensory nerve conduction velocity; SNAP: sensory nerve action potential; DTR: deep tendon reflexes; NT: not tested.