HLA‐DQB1, ‐DQA1, ‐DRB1 linkage disequilibrium and haplotype diversity in a Mestizo population from Guadalajara, Mexico

Abstract

HLA-DQB1, -DQA1, and -DRB1 genes were typed by polymerase chain reaction with sequence-specific primer (PCR-SSP) in 159 healthy volunteers from 32 families living in Guadalajara, Mexico. Three-locus genotype data from all family members were used to infer haplotypes in 54 unrelated individuals of the sample, from which estimate of segregating haplotype frequencies and linkage disequilibrium (LD) between loci were computed. Genotype distributions were concordant with Hardy-Weinberg expectations (HWE) for all three loci, and allele distributions were similar to the ones observed in other Latin-American populations. Of the 56 distinct three-site (DQB1-DQA1-DRB1) haplotypes observed in the sample, the five most common (i.e., with frequencies of five counts or more) were: *0302-*0301-*04, *0201-*0201-*07, *0301-*0501-*14, *0402-*0401-*08, and *0501-*0101-*01. These common three-locus haplotypes also contributed to the majority of the significant two-locus linkage disequilibria of these three sites.

HLA‐A and HLA‐B allele frequencies in a mestizo population from Guadalajara, Mexico, determined by sequence‐based typing

“…The genetic blend in Mexico and the rest of Latin America is so unique that some philosophers consider blending and “Latin‐Americanity” as indissoluble concepts (47), as the newly admixed mestizos rapidly surpassed the Native and Caucasian groups (13, 47). The population uniqueness is also supported by the absence of linkage disequilibrium secondary to admixture at the HLA class II region (14).…”

“…Reports on HLA class II in Mexico have been published (8,14,15,46), but high-resolution HLA class I studies are limited in number and sample size (2,3). On the other hand, studies on segregating HLA haplotypes are considered desirable (45), but only a few of them are known in Latin America (14,23,46). Consequently, this study, based upon probabilistic calculations, also has this kind of estimation restrictions.…”

“…The documented migratory flows to Guadalajara (Mexico) were mainly from the Spanish provinces Castile, Andalusia, Extremadura, and, to a lesser extent, Galicia and Portugal (13). Studies on HLA class II and other DNA polymorphisms from Jalisco have been published (7, 14–16), contributing to the knowledge of the genetic structure of the western Mexican mestizo population. However, at present, there is no gene frequency data for HLA class I genes in this region.…”

HLA class II haplotypes in Mexican systemic lupus erythematosus patients

“…This haplotype has been observed with a high frequency in SLE populations of different origins: Caucasians, Chinese, Japanese, and African Americans [29]. According to the reported haplotype frequencies and the origin of the Mexican Mestizo population [32,33] (http://www.allelefrequencies.net/ options.Asp), SLE might have been introduced to the native Mexican Amerindians by admixture with Caucasian populations. That is, the genetic admixture between Amerindians and Caucasian, mainly Spaniards, increased the risk of developing SLE in the Mexican Mestizo population.…”

Virtual crossmatching and epitope analysis in kidney transplantation: What the physician involved in kidney transplantation should know?

“…On the other hand, linkage disequilibrium is a phenomenon whereby alleles at adjacent HLA loci are inherited together more often than expected probabilistically 13 and is reported to be strong among DRB1, DRB3/4/5, DQA1, and DQB1. [21][22][23] Using this phenomenon, the alleles of other loci may be estimated from the allele typed previously, noting that it is not typing.…”