Abstract

A retrospective total population study of acute Werdnig-Hoffmann disease (spinal muscular atrophy type 1) has been undertaken in three counties of North-East England (Northumberland, Newcastle upon Tyne, and Durham). The gene frequency for the disease is q=0·00625 with a carrier frequency for this part of the English population of 1 in 80. The data suggest that there may be differences in gene frequency within the region sampled, a finding in keeping with other investigations of variations in gene frequency in this region. The suggestion that this disease is the second most common fatal autosomal recessive disease of childhood in Britain is confirmed. An hypothesis of heterozygote advantage due to relative resistance to epidemic poliomyelitis is presented to account for the high gene frequency observed.