Familial hypercholesterolaemia--a common genetic disorder in the Afrikaans population.

Serum cholesterol levels have been studied in three groups of young White South Africans. The mean levels were highest among the Jewish (195,7 mg/dl or 5,10 mmol/l), lowest among the Afrikaans (174,9 mg/dl of 4,55 mmol/l), and intermediate in the English-speaking Gentile population (180,0 mg/dl or 4,67 mmol/l). Levels were significantly higher in females than in males in the Jewish and English-speaking Gentile populations, but not significantly higher in Afrikaans females compared with males. Studies carried out on the families of individuals found to have serum cholesterol levels above 300 mg/dl (7,8 mmol/l) emphasized that, in addition to the serum cholesterol studies, detailed family studies are essential if an accurate diagnosis of familial hypercholesterolaemia (FH) is to be made. From such studies in the Afrikaans population and also from the known number of homozygotes for FH in one area of South Africa, all of whom came from Afrikaans families, it has been estimated that the frequency of the FH gene is unusually high in this population. It is postulated that the latter finding could help to explain the high incidence of and mortality rate from ischaemic heart disease in young White South Africans.