Pvu II and Stu I restriction fragment length polymorphisms of the low-density lipoprotein-receptor gene were used for receptor allele haplotype analysis in 6 unrelated white Afrikaans-speaking subjects with homozygous familial hypercholesterolaemia (FH). Five patients were homozygous for P-S+, one of four possible haplotypes, and 1 patient showed compound heterozygosity for P-S+ and P+S-. The haplotype distribution in these patients differed from the calculated distribution in the general Afrikaner population at the 5-10% level of significance. These data support the founder gene hypothesis advanced to account for the high frequency of FH in the Afrikaans population. Four non-Afrikaner homozygous FH patients, also investigated in this study, manifested a variety of haplotypes in conformity with the heterogeneity underlying FH reported by others.