Allele and haplotype frequencies at human leukocyte antigen class I and II genes in Venezuela's population

Abstract

Population studies represent an integral part and link in understanding the complex chain of host-pathogen interactions, disease pathogenesis, and MHC gene polymorphisms. Genes of Mongoloid, Caucasoid, and Negroid populations have created a distinctive HLA genetic profile in the Venezuelan population. Our objective was to determine the predominant HLA class I and II alleles and haplotype frequencies in the hybrid population of Venezuela. The study population consisted of 486 healthy unrelated native Venezuelans and 180 families. We examined the frequency of HLA A-B-C, HLA-DQ and HLA-DR genes by polymerase chain reaction and subsequent hybridization with sequence-specific oligonucleotide probes. Phenotypic, allelic and haplotype frequencies were estimated by direct counting and using the maximum-likelihood method. The predominant HLA class I alleles were A*02, A*24, A*68, B*35, B*44, B*51, B*07, B*15 and Cw*07. Regarding HLA class II, the most frequent alleles were DQB1*03 and DRB1*04, DRB1*15, DRB1*13, DRB1*07. The prevailing haplotype was HLA-A*02B*35 DQB1*03 DRB1*04. Some of these alleles and haplotype frequencies were predominantly present in Amerindians (A*02, A*24, B*35, Cw*07, DRB1*04, A*24 B*35). Previous reports have shown high incidence of A*02, B*44, B*51, DRB1*15, DRB1*13, DRB1*07 alleles in several European populations and A*68, B*07, B*15 alleles in African Americans, which could have contributed to the ethnic admixture of the Venezuelan population. We conclude that our results provide strong evidence that Venezuela's population represents an admixture of the primitive Mongoloid Aborigines, Caucasoid Europeans and Western African Negroid migrants.