Haptoglobin gene subtypes in three Brazilian population groups of different ethnicities

Abstract

Haptoglobin is a plasma hemoglobin-binding protein that limits iron loss during normal erythrocyte turnover and hemolysis, thereby preventing oxidative damage mediated by iron excess in the circulation. Haptoglobin polymorphism in humans, characterized by the Hp*1 and Hp *2 alleles, results in distinct phenotypes known as Hp1-1, Hp2-1 and Hp2-2, whose frequencies vary according to the ethnic origin of the population. The Hp*1 allele has two subtypes, Hp *1F and Hp *1S , that also vary in their frequencies among populations worldwide. In this work, we examined the distribution frequencies of haptoglobin subtypes in three Brazilian population groups of different ethnicities. The haptoglobin genotypes of Kayabi Amerindians (n = 56), Kalunga Afro-descendants (n = 70) and an urban population (n = 132) were determined by allele-specific PCR. The Hp*1F allele frequency was highest in Kalunga (29.3%) and lowest in Kayabi (2.6%). The Hp*1F/Hp*1S allele frequency ratios were 0.6, 1.0 and 0.26 for the Kayabi, Kalunga and urban populations, respectively. This variation was attributable largely to the Hp*1F allele. However, despite the large variation in Hp*1F frequencies, results of F ST (0.0291) indicated slight genetic differentiation among subpopulations of the general Brazilian population studied here. This is the first Brazilian report of variations in the Hp*1F and Hp*1S frequencies among non-Amerindian Brazilians.

Interactions among methylenetetrahydrofolate reductase (MTHFR) and cystathionine β-synthase (CBS) polymorphisms - a cross-sectional study: multiple heterozygosis as a risk factor for higher homocysteine levels and vaso-occlusive episodes

“…Although we did not conduct any studies of ancestry, these results confirm the great influence of our African ancestry even on Caucasian patients. As the population of Brasília is formed by migrants from all regions of Brazil, it tends to reflect the Brazilian population better than any other region (Miranda-Vilela et al, 2009. Finally, although this study was conducted with a convenience sample, this was composed of patients attended at HBDF, which is a publichealth system center for the diagnosis and treatment of blood disorders in adults in Brazil's Midwest, attending a large geo-economic region (Barbosa et al, 2014).…”

Association between interleukin 6 -174 G/C promoter gene polymorphism and runners' responses to the dietary ingestion of antioxidant supplementation based on pequi (Caryocar brasiliense Camb.) oil: a before-after study

“…Moreover, Brazil's large geographic size and the fact that different population groups have moved to different parts of the country has resulted in considerable phylogeographical heterogeneity (Parra et al ., 2003). As the population of Brasilia (the Federal Capital) is formed by migrants from all regions of Brazil, it tends to reflect the Brazilian population better than any other region (Miranda-Vilela et al ., 2009d; Hiragi et al ., 2011). In this regard, our results confirm a major influence of European ancestry in the IL-6 polymorphism studied here.…”