FREQUENCIES OF HLA-A AND HLA-B ALLELES IN A MEXICO-CITY MESTIZO SAMPLE

The aim of the present study was to evaluate the frequency of HLA-A an d HLA-B antigens in a sample of the Mexico City Mestizo population. Pr evious similar studies were done by other authors in nonrelated indivi duals, while the present investigation was performed in families (pare nts and offspring), and therefore, a more accurate estimate of gene an d haplotype frequencies was obtained, The predominant antigens in desc ending order are A2, A24, and A28 at the A locus, whereas B39 and B35 are at the B locus, all with gene frequencies above 0.1. As expected, the two more frequent haplotypes were A2-B16 and A2-B35 (considering m ain specificities), both with frequencies of 0.056. Seven of the 18 si gnificant delta values of the haplotypes (observed vs. expected) remai ned significant after correcting for the number of comparisons, indica ting the presence of linkage disequilibrium between the HLA-A and HLA- B regions. However, only A1-B8 and A19-B13 were found to be in disequi librium in another Mexico City Mestizo sample which had very similar H LA-A and HLA-B allele frequencies to those in the present survey, sugg esting that the biological significance of the other associations is r ather doubtful. (C) 1997 Wiley-Liss, Inc.