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.

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CONTEXT AND OBJECTIVE: Hemoglobinopathies are among the commonest and most widespread genetic disorders worldwide. Their prevalence varies according to ethnic composition and/or geographical region. The aim of this study was to investigate the presence of hemoglobinopathies and their association with ethnicity among 1,004 newborns, to confirm the guideline of the Brazilian National Neonatal Screening Program. DESIGN AND SETTING: Cross-sectional study conducted in a public referral hospital in the Triângulo Mineiro region, Minas Gerais, Brazil. METHODS: Qualitative assessment of hemoglobin was performed through electrophoresis on cellulose acetate: at alkaline pH to identify the hemoglobin (Hb) profile and at acid pH to differentiate Hb S from Hb D and Hb C from Hb E and others that migrate to similar positions at alkaline pH. Neutral pH was used to detect Hb Bart's identified in alpha thalassemia (α-thal). The elution method after electrophoresis was used to quantitatively assess hemoglobins. RESULTS: There was predominance of α-thal, with 105 cases (10.46%), followed by Hb S with 61 cases (6.08%, comprising 46 Hb AS, 2 Hb SS and 13 Hb S/α-thal), 9 cases (0.9%) of Hb AC and 6 cases (0.6%) suggestive of beta thalassemia (β-thal). The frequency of hemoglobinopathies was significantly higher among Afro-descendants. CONCLUSIONS: These findings corroborated of the National Neonatal Screening Program for diagnosing sickle cell disease and Hb C, Hb D, Hb E and β-thal hemoglobinopathies. RESUMO CONTEXTO E OBJETIVO:As hemoglobinopatias estão entre as alterações genéticas mais comuns e mundialmente difundidas, variando conforme a composição étnica e/ou geográfica. Nosso objetivo foi verificar a incidência de hemoglobinopatias por métodos de triagem laboratorial e sua associação com a etnia em 1.004 recém-nascidos. TIPO DE ESTUDO E LOCAL: Estudo transversal; realizado em um hospital público de referência do Triângulo Mineiro, Minas Gerais, Brasil. MÉTODOS: Avaliação qualitativa das hemoglobinas foi realizada por eletroforese em acetato de celulose: em pH alcalino para identificação do perfil hemoglobínico, em pH ácido para diferenciação das Hb S da Hb D e Hb C da Hb E, e outras que migrem em posições semelhantes em pH alcalino e em pH neutro para detecção de Hb Bart's, identificada na talassemia alfa (α-thal); e avaliação quantitativa das hemoglobinas pelo método de eluição após eletroforese. RESULTADOS: Houve predomínio da α-thal, com 105 (10,46%) casos, seguida da Hb S, com 61 casos (6,08% -46 Hb AS, 2 Hb SS e 13 Hb S/α-thal), 9 casos (0,9%) de Hb AC e 6 (0,6%) sugestivos de betatalassemia (β-thal). A incidência de hemoglobinopatias foi significantemente maior em afrodescendentes. CONCLUSÕES: Esses achados reforçam a importância do Programa Nacional de Triagem Neonatal para o diagnóstico das síndromes falciformes e hemoglobinopatias C, D, E e β-thal e robustecem os dados da literatura sobre a necessidade da pesquisa da α-thal em sangue de cordão (não identificada pelo Programa Nacional) e em pacientes com anemia ...

This study showed that the values of haematological parameters, especially haematocrit, Hb, MCV, MCH, MCHC and red blood cell distribution width (RDW), are lower in patients with IDA, especially when associated with α-thal and therefore it may be useful to discriminate between the different types of microcytic anaemia.

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