Table 1.
Neurophysiological Findings in the Study Family.*
| Subject No. | Age yr |
Sex | Demyelination | Axonopathy | Median-Nerve Entrapment | Diagnosis |
|---|---|---|---|---|---|---|
| I-1 | 80 | M | No | Motor: peroneal, 2.2 mV | Yes | |
| I-2 | 77 | F | No | Sural: absent; motor: peroneal, 0.5 mV; tibial, 2.8 mV | Yes | Axonal neuropathy |
| Maternal grandmother of proband | 90 | F | No | Normal | Yes; SCV, 43 m/sec | MMM |
| II-I | 58 | F | No | Normal | Yes; SCV, 46 m/sec | MMM |
| II-2 | 57 | M | No | Sural: absent; motor: peroneal, 0.2 mV; tibial, 1.4 mV; H-reflexes: 38 msec | Yes | Axonal neuropathy |
| III-1 | 37 | M | No | Normal | No | |
| III-2 | 35 | M | Yes | No | Yes; median-nerve motor TL, 14.9 msec; ulnar-nerve motor TL, 8.1 msec | CMT |
| III-3 | 34 | F | No | No | Yes; SCV, 42 m/sec; median-nerve motor TL, 4.4 msec | MMM |
| III-4 (proband) | 32 | M | Yes | No | Probably; median-nerve motor TL, 10.2 msec; ulnar-nerve motor TL, 7.5 msec | CMT |
| III-5 | 31 | F | No | No | No | |
| III-6 | 29 | F | Yes | No | Yes; median-nerve motor TL, 11.6 msec; ulnar-nerve motor TL, 6.2 msec | CMT |
| III-7 | 26 | F | No | Motor: peroneal, 36 m/sec; H-reflexes: 35 msec | Yes; SCV, 36 m/sec; median-nerve motor TL, 4.8 msec | MMM |
| III-8 | 25 | M | Yes | No | Yes; median-nerve motor TL, 9.2 msec; ulnar-nerve motor TL, 6.2 msec | CMT |
Subject I-1 was a carpenter for more than 50 years. The maternal grandmother of the proband is not included in the pedigree. The ages listed are the ages at the time at which the subjects were evaluated. The normal value for median-nerve motor terminal latency (TL) is less than 4.0 msec and for sensory conduction velocity (SCV) is 48 m/sec or more. The diagnosis column lists the conclusion based on the aggregate findings: severe, widespread slowing of conduction was interpreted as evidence of demyelination, and low-potential amplitudes in multiple nerves with relative preservation of conduction velocities were interpreted as evidence of axonal damage. CMT denotes Charcot–Marie– Tooth disease, CTS the carpal tunnel syndrome, and MMM mild mononeuropathy of the median nerve.