α-thalassemia, HbS, and β-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%) were heterozygous for -α3,7 thalassemia; seven of them (29.2%) were originally from the southern region, whereas one of them (3.6%) was from the northern region; the differences between both regions were statistically significant (p = 0.016 +/-0.003). The only structural mutation detected was βs, which is typical of African populations. Four individuals (10%) were heterozygous for βs, three of them (13.6%) from the South, and one (5.6%) from the North. The βs haplotypes were analyzed in eight individuals: two were homozygous βs/βs, two were heterozygous βs/βthal, and four were heterozygous βs/βA. This haplotype distribution (60% Bantu, 20% Benin, and 20% 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. Copyright by the Brazilian Society of Genetics.