JUVENILE, AUTOSOMAL DOMINANT, DISTAL SPINAL MUSCULAR ATROPHY AND NEUROSENSORIAL DEAFNESS NOT LINKED TO CHROMOSOME 12q24

Abstract

Distal spinal muscular atrophy, also classified as a spinal form of Charcot‐Marie‐Tooth‐disease, or distal hereditary motor neuropathy, is genetically heterogeneous and both autosomal dominant and autosomal recessive inheritance have been described. Recently, in an autosomal‐dominant Belgian family with juvenile onset in distal leg muscles, a significant linkage was obtained with markers located at chromosome 12q24 (Timmermann et al. 1996).We describe a three‐generation Italian kindred with distal spinal muscular atrophy showing autosomal dominant inheritance, onset at 8–10 years with leg weakness and atrophy, later involvement of distal arm muscles, and eventually proximal muscles. The older patients also had neurosensorial deafness. To confirm the previous genetic findings, we used four microsatellite markers located at chromosome 12q23‐24: D12S86, D12S1612, D12S1349, PLA2A. No support for linkage with 12q24 was found in this family, which indicates a genetic heterogeneity in juvenile onset autosomal dominant distal spinal muscular atrophy.