Neuropathy, Hereditary Motor And Sensory, With Excessive Myelin Folding Complex, Autosomal Recessive

Clinical Features

Ohnishi et al. (1989) described 2 unrelated Japanese patients, each with consanguineous parents, who had a motor and sensory neuropathy of the hypertrophic type with excessive myelin outfolding in myelinated fibers, as well as segmental demyelination and remyelination. One patient was a 15-year-old boy who complained of muscle weakness in both the upper and lower limbs and hypesthesia in the distal part of the lower limbs. His parents were first cousins. Insidious weakness of the legs and foot deformity began at 7 years of age. By 12 years of age he had increasing difficulty in manipulating the tiny parts of airplane models. The second patient was a 49-year-old Japanese woman who complained of weakness of the hands and disturbance of gait. Her parents were second cousins. Thenar muscle wasting had first been noted when she was in her 20s; weakness of the hands was first noted at 47 years of age. Schenone et al. (1991) studied 3 cases of recessively inherited hereditary motor and sensory neuropathy (HMSN) clearly different from other reported forms and closely resembling that in the 2 cases reported by Ohnishi et al. (1989). Focal and irregularly outfolded myelin was observed particularly in longitudinal sections of teased fibers by electron microscopy. Barbieri et al. (1994) described brother and sister, aged 35 and 37 years, respectively, in whom this disorder first became manifest at about age 10 years. Their parents were first cousins.

See CMT4B1 (601382) and CMT4B2 (604563) for autosomal recessive disorders with a similar phenotype.