1985 Volume 17 Issue 6 Pages 500-506
Two cases (Cases 1 and 2) of hereditary motor and sensory neuropathy (HMSN) type I and two cases (Cases 3 and 4) of HMSN type II were described. All cases were male and aged from 3y5m to 11y11m with the onset in early childhood. Cases 1 and 2 were siblings whose father was also similarly affected, suggesting autosomal dominant inheritance. However, Case 2, the younger brother of Case 1, was still in the subclinical state.
Muscle weakness and wasting were noticed below the knee, especially in the peroneal muscle group, in Cases 1, 3 and 4. Distal portions of upper extremities were also affected and sensory disturbance was noticed in Case 4. Motor conduction velocities were considerably decreased in Cases 1 and 2, mildly decreased in Case 3, and normal in Case 4. Sensory conduction velocities were mildly decreased in Cases 1, 2 and 3, and normal in Case 4. Neurogenic potentials were detected in all cases with EMG. Pathological studies including light and electron microscopic observations, fiber teasing and morphometry of sural nerve biopsy material from Cases 1, 2 and 3 were performed. A remarkable decrease of myelinated fiber density with a unimodal type of histogram and segmental de/remyelination were found in both Cases 1 and 2. The small axons surrounded by excessively thick myelin sheath as the main pathalogical change, and myelinated fiber diameter analysis revealed a unimodal pattern with loss of large myelinated fibers. Ouvrier et al. (1981) reported 11 cases of HMSN which did not fall into Dyck's classification because of the rapidly progressive clinical course. In our series, Cases 3 and espescially 4 had the characteristics similar to those in cases reported by Ouvrier. Careful follow-up observations of those two cases would be necessary for further evaluation.
