Autosomal recessive motor and sensory neuropathy with excessive myelin outfolding in two siblings.

Two siblings, a 35-year-old male and a 37-year-old female, offspring of first cousins, presented with a hereditary motor and sensory neuropathy with type I clinical features which began to manifest at about age 10 years. Nerve biopsy in the proband showed it to be a type characterized by excessive myelin outfolding. Morphometric study revealed hypomyelination with focal thickenings due to outfoldings. Clinical, electrophysiological and morphological findings are virtually identical to those described by Ohnishi et al. The peculiarity of the neuropathological picture suggests a particular form of hereditary motor and sensory neuropathy.