Distribution of HLA-A, -B and -DRB1 genes and haplotypes in the Tujia population living in the Wufeng Region of Hubei Province, China.

BACKGROUND

The distribution of HLA alleles and haplotypes varies widely between different ethnic populations and geographic areas. Before any genetic marker can be used in a disease-associated study it is therefore essential to investigate allelic frequencies and establish a genetic database.

METHODOLOGY/PRINCIPAL FINDINGS: This is the first report of HLA typing in the Tujia group using the Luminex HLA-SSO method HLA-A, -B and -DRB1 allelic distributions were determined in 124 unrelated healthy Tujia individuals, and haplotypic frequencies and linkage disequilibrium parameters were estimated using the maximum-likelihood method. In total 10 alleles were detected at the HLA-A locus, 21 alleles at the HLA-B locus and 14 alleles at the HLA-DRB1 locus. The most frequently observed alleles in the HLA-I group were HLA-A02 (35.48%), A11 (28.23%), A24 (15.73%); HLA-B40 (25.00%), B46 (16.13%), and B15 (15.73%). Among HLA-DRB1 alleles, high frequencies of HLA-DRB109 (25.81%) were observed, followed by HLA-DRB115 (12.9%), and DRB112 (10.89%). The two-locus haplotypes at the highest frequency were A02-B46A (8.47%), followed by A11-B40 (7.66%), A02-B40 (8.87%), A11-B15 (6.45%), A02-B15 (6.05%), B40-DRB109 (9.27%) and B46-DRB109 (6.45%). The most common three-locus haplotypes found in the Tujia population were A02-B46-DRB109 (4.84%) and A02-B40-DRB1*09 (4.03%). Fourteen two-loci haplotypes had significant linkage disequilibrium. Construction of a neighbor-joining phylogenetic tree and principal component analysis using the allelic frequencies at HLA-A was performed to compare the Tujia group and twelve other previously reported populations. The Tujia population in the Wufeng of Hubei Province had the closest genetic relationship with the central Han population, and then to the Shui, the Miao, the southern Han and the northern Han ethnic groups.

CONCLUSIONS/SIGNIFICANCE: These results will become a valuable source of data for tracing population migration, planning clinical organ transplantation, carrying out HLA-linked disease-associated studies and forensic identification.