Cystic fibrosis in the South West African Afrikaner. An example of population drift, possibly with heterozygote advantage.
An incidence of the genetic recessive disease cystic fibrosis (mucoviscidosis) far in excess of that reported recently from other countries, has been encountered in the South West African Afrikaner. This has probably resulted from the immigration of a segment of the South African Afrikaner population rich in the gene, into South West Africa, where, for religious reasons and reasons of geographical isolation, the gene has persisted and, perhaps, increased in frequency. Malaria, which killed many of the early settlers, might have selectively spared carriers of the gene, thus enriching its occurrence in the population. Details of patients, particularly with regard to the criteria of diagnosis, are given with the relevant population and birth figures, from which an estimate of the incidence of the disease and of its carrier rate has been made. Screening of the newborn for the condition and the compiling of a register of potential and obligatory carriers are also discussed.