α-Thalassemia: Genotypic Profile Associated with Ethnicity and Hematological Differentiation of Iron Deficiency Anemia in the Region of Uberaba, Minas Gerais, Brazil

Abstract

α-Thalassemia (α-thal) is a hereditary hemoglobinopathy characterized by microcytic anemia due to impaired production of α chains of human globin. Brazilian studies show that the most common genotype is an −α^3.7 deletion with the loss of one or two α genes. As the production of α chains is not as accentuated in these cases, the correct diagnosis can only be achieved through molecular analysis that is not usually routinely performed by laboratories. We investigated the occurrence of α-thal babies born between September 2011 to January 2013 at the hospital of the Universidade Federal do Triângulo Mineiro (UFTM), Uberaba, Brazil, and blood donors of the Uberaba Regional Blood Center, Hemominas Foundation, Uberaba, Brazil, correlating it with ethnicity and differences between hematological parameters of donors, α-thal and iron deficiency patients. α-Thalassemia was investigated for the most common deleted alleles (−α^3.7, −α^4.2, – –^SEA, – –^FIL, – –^THAI, −(α)^20.5 and – –^MED). The incidence in newborns was 13.16% with a predominance of heterozygosity for the −α^3.7 genotype (12.35%), followed by the −α^3.7/−α^3.7 (0.46%) and αα/−α^4.2 genotypes (0.35%). In blood donors, the prevalence of α-thal was 14.89%, with all cases being heterozygous for the −α^3.7 deletion. There was an association of the α-thal genotype with African ancestors for both groups, thereby confirming published data and showing the strong influence of Blacks on the composition of the population of Brazil’s southeastern region. Minor changes were found between hematological parameters of blood donors with iron deficiency and α-thal that did not contribute to the differential diagnosis between the two types of anemia.

• α-Thalassemia (α-thal)
• ethnic groups
• genotype
• red blood cell (RBC) count

Acknowledgements

The authors acknowledge all participants and parents for their cooperation in this study.

Declaration of interest

The authors are grateful for the financial support and other bases of the Hemominas Foundation, FAPEMIG (Fundação de Amparo à Pesquisa do Estado de Minas Gerais), and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.