Haplotype analysis of the linkage group HLA-A: HLA-B : Bf in Japanese.

Three hundred four HLA-A : HLA-B : Bf haplotypes of the Japanese population as deduced by family analysis are described. Several linkage disequilibriums were observed in the following two-factor haplotypes: HLA-A and HLA-B, HLA-A and Bf, and HLA-B and Bf. Positive linkage disequilibriums between HLA-A and HLA-B noted in the present study seem to be Japanese specific when compared with the results obtained from other ethnic groups reported so far. The striking finding is that three HLA-B : Bf haplotypes, namely B12-BfF, B15-BfF, and B7-BfS, are common and show linkage disequilibrium in both Japanese and European Caucasians (German). This finding not only confirms the proximity of the HLA-B and Bf loci but also suggests that the interaction of the two genes plays an important role in the maintenance of stable linkage disequilibrium.