Fanconi anemia: another disease of unusually high prevalence in the Afrikaans population of South Africa.

We have investigated the prevalence of homozygous and heterozygous Fanconi anemia (FA) in the Afrikaans community of the southern Transvaal Province. The minimum birth incidence of FA in white, Afrikaans-speaking South Africans was estimated to be 1 in 22,000, with the calculated heterozygote prevalence being approximately 1 in 77. Alternatively, based on a point prevalence of 1 in 26,000, the carrier rate may be estimated as 1 in 83. It is postulated that this unusually high frequency of the gene for FA is attributable to founder effect.