HLA Class I and Class II Genes Distribution of the Iranian Sistanis.

BACKGROUND: The high polymorphism in the human leukocyte antigen (HLA) genes can be used as an identity of individuals to compare with other populations. This extreme polymorphism in the HLA system is accountable for the differences in alleles and haplotypes among ethnic groups, populations, and the inhabitants of many regions. OBJECTIVE: To define the frequency of HLA alleles and haplotypes among the Sistanis, Sistani/Zaboli population in Iran. METHODS: In this study, genotyping of class I (A, B, C) and class II HLA (DRB1, DQA1, DQB1) loci were determined in 90 unrelated Iraninan Sistani people and the results were compared with 474,892 HLA chromosomes from a diverse worldwide population. RESULTS: The highest frequently observed alleles in this study were A*02:01, B*35:01, C*12:03, C*06:02, DRB1*11, DQA1*05:05, and DQB1*03:01. Furthermore, the most frequent 3-locus haplotypes were A*02:01-B*50:01*C*06:02, DRB1*11-DQB1*03:01-DQA1*05:05, and A*02:01-B*50:01-DRB1*07. The most occurring 4-locus haplotypes were A*02:01-B*50:01-C*06:02-DRB1*07 and A*02:01-B*50:01-DRB1*07-DQB1*02:01. A*02:01-B*50:01-C*06:02-DRB1*07-DQB1*02:01 and A*02:01-B*50:01-C*06:02-DRB1*07-DQB1*02:01-DQA1*02:01 were determined to be the predominant 5- and 6-locus haplotypes, respectively. The heat maps and multiple correspondence analyses based on the frequency of HLA alleles showed that Sistanis share a common genetic inheritance with other Iranian ethnic groups such as the people from Yazd and Fars except some differences with Baluchis, Iranian Jews, Lurs of Kohgiluyeh/Buyerahmad, and Arabs of Fars, which may arise from the admixture of these groups or with foreign subgroups over centuries, and also a close relatedness with some European populations. CONCLUSION: These data could be useful for finding better donor matches for organ transplantation among Sistanis or other related Iranian ethnic groups, epidemiological studies of HLA-associated diseases, handling HLA genomics and mapping the migration pattern of different ethnic group.

Human Leukocyte Antigen (HLA) Class I and II Polymorphism in Iranian Healthy Population from Yazd Province.

The major histocompatibility complex (MHC) genes are the most polymorphic loci in the human genome and have been widely studied in various populations and ethnic groups. Investigations into the HLA genes and proteins have been useful tool for anthropological, transplantation and disease association studies. The polymorphism of the HLA class I (A, B, C) and class II (DRB1, DQA1, DQB1) genes were investigated in 90 unrelated Iranian individuals from Yazd province located in the center of Iran using sequence-specific primers (PCR-SSP). Allele and haplotype frequencies, expected/observed heterozygosity, unbiased expected heterozygosity, number of effective alleles, deviations from Hardy-Weinberg (HW) equilibrium and genetic diversity were computed. A total of 23, 48, 23, 24, 13 and 16 alleles for HLA-A, -B,-C, -DRB1, -DQA and -DQB loci were determined, respectively in the population study. The most frequent allele identified in this study were A*02:01 (18.889%), HLA-B* 51:01 (12.778%), HLA-C* 12:03 (17.033%), HLA-DRB* 11 (24.4%), HLA-DQA* 05:05 (20.55%) and HLA-DQB*03:01 (22.8%).Furthermore, the most frequent 3-locus haplotypes were DRB*11-DQA*05:01-DQB*03:01 (21.1%), HLA-A*02:01- B *50:01- DRB*07:01 (4.9%) and A*26:01 -B* 38:01 -C*12:03(5%). The most 4-locus haplotype were A*11:01 -B* 52:01 -C*12:03 -DRB!*15(2.5%) and A*02:01 -B* 50:01 -DRB1*07:01 -DQB1*02:01(4.5%). The heterozygosity of the study population was confirmed the expected value and not deviated from Hardy-Weinberg equilibrium for all loci (p>0.05). Our study shows a close relatedness between Yazd population and other ethnic group of Iran despite some differences, which may be due to admixture of each one of these groups with each other or foreigner subpopulations during centuries. Moreover, the results of this study suggest that the Iranian population from Yazd province is in close vicinity with the Caucasians populations and far from the Korean and Japanese populations.