Investigations on Huntington's disease in the Canadian Prairies. I. Prevalence.

One hundred and sixty-two confirmed cases of Huntington's disease have been ascertained in the provinces of Saskatchewan and Manitoba in the Canadian Prairies. They were encountered in 97 sibships which were derived from 58 kindreds. The prevalence of the disorder was estimated to be 8.4 per 100,000 individuals. Taking into account the mean age of onset of the disorder, 23.3 per 100,000 individuals are expected to be heterozygous for the Huntington's disease allele, the frequency of which is thus computed to be 0.0001168.