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%) were heterozygous for -a 3,7 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 b S , which is typical of African populations. Four individuals (10%) were heterozygous for b S , three of them (13.6%) from the South, and one (5.6%) from the North. The b S haplotypes were analyzed in eight individuals: two were homozygous b S /b S , two were heterozygous b S /b thal , and four were heterozygous b S /b A . 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.

Prevalence of common hemoglobin variants in an afro-descendent Ecuadorian population

“…Studies indicate that Native American individuals have lower hemoglobin variants than Afro-descendants and mestizos [3]. On the other hand, alpha-thalasemia, has been reported with high prevalence in afro-descendent populations from Uruguay (15.4%) and Brazil (20 - 25%) [6,19]. …”

“…This high frequency is expected in afro-descendent populations, but it is lower than the frequency observed in most populations (from 12.4% to 40.5%) from the Cayapas River, Esmeraldas [9,10]. Compared with afro-descendent populations from other Latin American countries, Hb AS frequency from the Ambuqui population was higher than populations from Peru (5%), Colombia- (4.65%) and Costa Rica (8.2%), Uruguay (10%), Brazil (0-13%) but lower than Venezuela (19.1%) [3,6,13-15,20]. The lower frequency reported in the Ambuqui populations compared with Esmeraldas populations could be influenced by the historical origins of afro-descendant populations in Ecuador.…”

“…Clinical severity of this pathology is influenced by the amount of genes that present changes affecting the structure of the globin chain. Alpha-thalassemia occur mainly in Africa, Asia and the Mediterranean basin while beta-thalassemia are found mostly in Asia and the Mediterranean basin [6]. Alpha and beta-thalassemia have been detected in low frequencies in Uruguayan afro-descendent population as well as populations from Venezuela with different ethnic origins [3,6].…”

Liver Enzymes in Children with beta-Thalassemia Major: Correlation with Iron Overload and Viral Hepatitis

“…Thalassemia is among the most common genetic disorders, and nearly 7% of the world population carry a hemoglobinopathy [ 1 ]. The burden of this disorder in many regions is of such a magnitude that it represents a major public health concern [ 2 ].…”

Deranged liver enzyme status in thalassemicpaediatric patients- is it hepatitis or iron overload?

“…[1] The burdenof this disorder in many regions is of such amagnitude that it represents a major public healthconcern. [2] Transfusion therapy which is the mainway of treatment allows for normal growth andsuppresses ineffective erythropoiesis.…”