Alpha-thalassemia, HbS, and beta-globin gene cluster haplotypes in two Afro-Uruguayan sub-populations from northern and southern Uruguay

ABSTRACT

Hemoglobinopathies are the most common monogenic disorders worldwide; however, they have never been systematically studied from a genetic perspective in Uruguay. In this study, we determined the frequencies of hemoglobin variants in Afro-Uruguayans. A sample of 52 healthy unrelated Afro-Uruguayans from the northern (N = 28) and southern (N = 24) regions of the country was analyzed. Eight individuals (15.4 percent) were heterozygous for -alpha3,7thalassemia; seven of them (29.2 percent) were originally from the southern region, whereas one of them (3.6 percent) was from the northern region; the differences between both regions were statistically significant (p = 0.016 +/-0.003). The only structural mutation detected was betaS, which is typical of African populations. Four individuals (10 percent) were heterozygous for betaS, three of them (13.6 percent) from the South, and one (5.6 percent) from the North. The betaS haplotypes were analyzed in eight individuals two were homozygous betaS/betaS, two were heterozygous betaS/betathal, and four were heterozygous betaS/betaª. This haplotype distribution (60 percent Bantu, 20 percent Benin, and 20 percent Bantu A2) is in agreement with historical records reporting a predominantly Bantu origin for the enslaved Africans brought to Uruguay. Even though this is a preliminary study, due to the small sample size, our results are suggestive of a relatively high incidence of hemoglobinopathies in the Afro-Uruguayan population.