Antigen, allele, and haplotype frequencies report of the ASHI minority antigens workshops: part 1, African-Americans.

Abstract HLA typing was performed on 977 African Americans residing throughout most of the United States. Class I and class II antigens and class II alleles were defined for all individuals and class I alleles were determined for a subset of individuals. The occurrence of 854 of the individuals in family groups permitted direct counting of allele and haplotype frequencies. The data were analyzed for antigen, allele, and haplotype frequencies; recombination frequencies; segregation distortion; distribution of haplotype frequencies; linkage disequilibria; and geographic distribution of DR antigens. Tables of the antigen, allele, the most common two and three point haplotypes, and 88 extended haplotypes that include class I and class II alleles are presented. Notable findings include a lower than expected frequency of recombination between the B and DR loci (θ = 0.0013), lower than expected frequency of inheritance (44.5% vs 54.5%) of the DRB1∗1503; DQB1∗0602 haplotype, lower than anticipated linkage disequilibrium values for DR; DQ haplotypes, and a skewed geographic distribution of DR antigens.