Hereditary motor and sensory polyneuropathy (peroneal muscular atrophy)

SUMMARY 1. The clinical, electrodiagnostic and nerve biopsy findings gained in a study of 17 families with hereditary motor and sensory polyneuropathy of autosomal dominant inheritance (peroneal muscular atrophy) are presented. 2. The families fall into two groups: the first, of 12 families, shows in all the affected individuals examined a marked reduction in nerve conduction velocity; in the second group of five families no individuals examined show a marked reduction in conduction velocity. Many, but not all, of the first group show palpable nerve hypertrophy. None in the second group does. In the first group, six nerve biopsies all show conoentric Schwann cell proliferation around myelinated axons or with no central axon, whether peripheral nerve thickening was found or not. No biopsies have been taken in the second group. 3. The electrodiagnostic findings are held to show that at least two different autosomal loci are involved in the genesis of the disorder. In addition, the clinical findings in the first group are held to indicate the possibility of further genetic heterogeneity in that group. 4. Data relating to age of onset and its correlation between parents and children, between sibs and between first cousins are discussed; they indicate the possibility of allelic modification in the production of the extensive intrafamilial variation found in all families. 5. It is held that the classical diagnostic categories of peroneal muscular atrophy, hereditary hypertrophic polyneuropathy and the Roussy-Levy syndrome cannot be applied to families and are poor descriptions of genetic entities though they may describe individual cases. It is suggested that hereditary motor and sensory polyneuropathy of autosomal dominant inheritance is at present a satisfactory title for the group of disorders.