ABSTRACT:

Objective:

To describe the prevalence of hemoglobinopathies in the Brazilian adult population, according to laboratory tests from the National Health Survey.

Methods:

A descriptive study was carried out with National Health Survey laboratory data collected between 2014 and 2015. The hemoglobinopathies test was performed using the High Performance Liquid Chromatography method. The results of the individual tests were interpreted as providing normal, homozygous or heterozygous results for S, C and D hemoglobin, in addition to other possible hemoglobinopathies. Prevalence of hemoglobinopathies according to gender, skin color, region, age and schooling was estimated.

Results:

Hemoglobinopathies were present in 3.7% of the population. The main ones were the sickle cell trait (2.49%), thalassemia minor (0.30%) and suspected thalassemia major (0.80%). In relation to the sickle cell trait and suspected thalassemia major, there was a statistically significant difference for the skin color variable (p<0.05). The prevalences found for sickle cell trait according to skin color was: 4.1% among dark-skinned blacks, 3.6% among light-skinned blacks, 1.2% among whites, and 1.7% among others.

Conclusion:

The most prevalent hemoglobinopathies were the sickle cell trait and minor thalassemia, and were predominate among light- and dark-skinned black people. The study helps in identifying hemoglobinopathies and in genetic counseling in pre-conception.

Keywords:
Sickle cell anemia; Sickle cell trait; beta-Thalassemia; Hemoglobin C; Fetal hemoglobin; Neonatal screening

INTRODUCTION

Hemoglobin (Hb) is a protein present in red blood cells and its main function is to transport oxygen (O₂) from the lungs to peripheral tissues. It has a quaternary structure composed of two alpha (α) and two beta (β) globin chains¹1. Thom CS, Dickson CF, Gell DA, Weiss MJ. Hemoglobin Variants: Biochemical Properties and Clinical Correlates. Cold Spring Harb Perspect Med 2013; 3(3): a011858. http://doi.org/10.1101/cshperspect.a011858
http://doi.org/10.1101/cshperspect.a0118... ^,22. Storz JF, Opazo JC, Hoffmann FG. Gene duplication, genome duplication, and the functional diversification of vertebrate globins. Mol Phylogenet Evol 2013; 66(2): 469-78. http://doi.org/10.1016/j.ympev.2012.07.013
http://doi.org/10.1016/j.ympev.2012.07.0... . Each chain is associated with a heme prosthetic group that is attached to an iron atom (Fe²⁺), which allows oxygen binding in blood cells¹1. Thom CS, Dickson CF, Gell DA, Weiss MJ. Hemoglobin Variants: Biochemical Properties and Clinical Correlates. Cold Spring Harb Perspect Med 2013; 3(3): a011858. http://doi.org/10.1101/cshperspect.a011858
http://doi.org/10.1101/cshperspect.a0118... ^,22. Storz JF, Opazo JC, Hoffmann FG. Gene duplication, genome duplication, and the functional diversification of vertebrate globins. Mol Phylogenet Evol 2013; 66(2): 469-78. http://doi.org/10.1016/j.ympev.2012.07.013
http://doi.org/10.1016/j.ympev.2012.07.0... .

Some mutations can modify amino acids and cause changes in functional effects, such as erythrocyte elasticity and even affinity with O₂³3. Frasca D, Dahyot-Fizelier C, Catherine K, Levrat Q, Debaene B, Mimoz O. Accuracy of a continuous noninvasive hemoglobin monitor in intensive care unit patients. Crit Care Med 2011; 39(10): 2277-82. http://doi.org/10.1097/CCM.0b013e3182227e2d
http://doi.org/10.1097/CCM.0b013e3182227... ^,44. Bren KL, Eisenberg R, Gray HB. Discovery of the magnetic behavior of hemoglobin: A beginning of bioinorganic chemistry. Proc Natl Acad Sci USA 2015; 112(43): 13123-7. http://doi.org/10.1073/pnas.1515704112
http://doi.org/10.1073/pnas.1515704112... . Thus, most abnormal hemoglobin result from the total or partial substitution of one amino acid for another in one of the globin chains³3. Frasca D, Dahyot-Fizelier C, Catherine K, Levrat Q, Debaene B, Mimoz O. Accuracy of a continuous noninvasive hemoglobin monitor in intensive care unit patients. Crit Care Med 2011; 39(10): 2277-82. http://doi.org/10.1097/CCM.0b013e3182227e2d
http://doi.org/10.1097/CCM.0b013e3182227... ^,44. Bren KL, Eisenberg R, Gray HB. Discovery of the magnetic behavior of hemoglobin: A beginning of bioinorganic chemistry. Proc Natl Acad Sci USA 2015; 112(43): 13123-7. http://doi.org/10.1073/pnas.1515704112
http://doi.org/10.1073/pnas.1515704112... . These structural and functional changes are called hemoglobinopathies.

It is estimated that 1.1% of couples worldwide are at risk of having children with some hemoglobinopathy and 0.27% of newborns are affected⁵5. World Health Organization. Global epidemiology of haemoglobin disorders and derived service indicators. Bulletin of the World Health Organization [Internet]. 2008 [acessado em 15 jan. 2018]; 86(6): 417-96. Disponível em: Disponível em: http://www.who.int/bulletin/volumes/86/6/06-036673/en/
http://www.who.int/bulletin/volumes/86/6... . In low-income countries, 3.4% of children with these diseases die before the age of 5, and in Africa this figure reaches 6.4%⁵5. World Health Organization. Global epidemiology of haemoglobin disorders and derived service indicators. Bulletin of the World Health Organization [Internet]. 2008 [acessado em 15 jan. 2018]; 86(6): 417-96. Disponível em: Disponível em: http://www.who.int/bulletin/volumes/86/6/06-036673/en/
http://www.who.int/bulletin/volumes/86/6... .

Among hemoglobinopathies, sickle cell disease (HbS) is considered to be the most common, followed by thalassemia, as well as other less prevalent ones, such as hemoglobin C (HbC), hemoglobin D (HbD), the persistence of fetal hemoglobin (HbF) and other rarer ones (over 200 subtypes)⁶6. Kohne E. Hemoglobinopathies: Clinical Manifestations, Diagnosis, and Treatment. Dtsch Ärztebl Int 2011; 108(31-32): 532-40. http://doi.org/10.3238/arztebl.2011.0532
http://doi.org/10.3238/arztebl.2011.0532... .

Sickle cell disease is caused by a single mutation in the composition of the β-globin chain, resulting in a conformational change called hemoglobin S (HbS)⁷7. Odièvre M-H, Verger E, Silva-Pinto AC, Elion J. Pathophysiological insights in sickle cell disease. Indian J Med Res 2011; 134(4): 532-7.. However, when the individual inherits the HbS gene from one parent and the hemoglobin A (HbA) from the other, he or she will carry the sickle cell trait. In this situation, sickle cell disease does not manifest itself; the individual is asymptomatic, has no physical abnormality, hematologic findings are normal, and life expectancy is similar to that of the general population⁸8. Murao M, Ferraz MHC. Traço falciforme: heterozigose para hemoglobina S. Rev. Bras. Hematol. Hemoter 2007; 29(3): 223-5. http://dx.doi.org/10.1590/S1516-84842007000300006
http://dx.doi.org/10.1590/S1516-84842007... ^,99. Brasil. Ministério da Saúde. Traço falciforme: consenso brasileiro sobre atividades esportivas e militares [Internet]. Brasília: Ministério da Saúde; 2015 [acessado em 9 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/traco_falciforme_consenso_brasileiro_atividades.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... .

Thalassemia is a syndrome characterized by the absence or marked decrease in the synthesis of one or more hemoglobin-forming globin chains (α, β, γ, δ)¹⁰10. Forget BG, Bunn HF. Classification of the Disorders of Hemoglobin. Cold Spring Harb Perspect Med 2013; 3(2): a011684. http://doi.org/10.1101/cshperspect.a011684
http://doi.org/10.1101/cshperspect.a0116... ^,1111. Zago MA. Talassemias. In: Zago MA, Falcão RP, Pasquini R, editores. Tratado de hematologia. São Paulo: Atheneu; 2013. p. 225-38.. The most common forms of the disease are types α and β, which are the second most frequent and are of greater clinical importance. They present as major thalassemia (the most severe because it is a homozygous carrier) and minor thalassemia, or thalassemic trait, which is genetically characterized by the inheritance of a single mutant gene¹⁰10. Forget BG, Bunn HF. Classification of the Disorders of Hemoglobin. Cold Spring Harb Perspect Med 2013; 3(2): a011684. http://doi.org/10.1101/cshperspect.a011684
http://doi.org/10.1101/cshperspect.a0116... ^,1111. Zago MA. Talassemias. In: Zago MA, Falcão RP, Pasquini R, editores. Tratado de hematologia. São Paulo: Atheneu; 2013. p. 225-38.. The reduction in the synthesis rate of β-globin is smaller, but it is sufficient to cause a slight degree of polyglobulia and anemia (reduction of hemoglobin), with intense microcytosis and hypochromia, as well as increased red cell osmotic resistance¹²12. Brasil. Ministério da Saúde. Orientações para diagnóstico e tratamento das Talassemias Beta [Internet]. Brasília: Ministério da Saúde ; 2016 [acessado em 9 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/orientacoes_diagnostico_tratamento_talassemias_beta.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... .

HbC carriers, also have β-globin chain mutations, but with the substitution of another amino acid. However, this mutation is considered to be benign in relation to sickle cell disease, since sickling is not part of its pathophysiology¹³13. Piel FB, Howes RE, Patil AP, Nyangiri OA, Gething PW, Bhatt S, et al. The distribution of haemoglobin C and its prevalence in newborns in Africa. Sci Rep 2013; 3: 1671. http://doi.org/10.1038/srep01671
http://doi.org/10.1038/srep01671... .

HbF is the predominant form of hemoglobin in fetuses during pregnancy and it is essential for the distribution of oxygen in the fetal phase. After birth, its expression gradually decreases and is replaced by HbA¹⁴14. Akinsheye I, Alsultan A, Solovieff N, Ngo D, Baldwin CT, Sebastiani P, et al. Fetal hemoglobin in sickle cell anemia. Blood 2011; 118(1): 19-27. http://doi.org/10.1182/blood-2011-03-325258
http://doi.org/10.1182/blood-2011-03-325... , however genetic factors may prevent this substitution, leading to a continuous synthesis of HbF, and thus a persistence of HbF¹⁵15. Manca L, Masala B. Disorders of the synthesis of human fetal hemoglobin. IUBMB Life 2008; 60(2): 94-111. https://doi.org/10.1002/iub.4
https://doi.org/10.1002/iub.4... ^,1616. Costa VA, Acedo MJ, Polimeno NC, Bertuzzo CS. Contribuição para a estimativa da freqüência populacional da Persistência Hereditária da Hemoglobina Fetal no Brasil. Cad Saúde Pública 2002; 18(5): 1469-71. http://dx.doi.org/10.1590/S0102-311X2002000500040
http://dx.doi.org/10.1590/S0102-311X2002... .

A laboratory diagnosis of these hemoglobinopathies in children starting at 4 months of age can be made by electrophoresis or by high performance liquid chromatography (HPLC). The latter is a methodology with higher sensitivity and specificity, which increases the reliability of the results and the correct diagnosis. Additionally, it is recommended by the Brazilian National Neonatal Screening Program (Programa Nacional de Triagem Neonatal - PNTN), for diagnosing hemoglobinopathies in newborns¹⁷17. Brasil. Ministério da Saúde. Doença falciforme: Atendimento odontológico: capacidade instalada dos hemocentros coordenadores [Internet]. Brasília: Ministério da Saúde ; 2015 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doenca_falciforme_atendimento_odontologico.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... . In Brazil, the National Health Survey (Pesquisa Nacional de Saúde - PNS), which produces data on the health status and lifestyle of the Brazilian population, collected blood from a subsample of respondents for laboratory testing. Eleven types of exams were performed, including the screening for HbS and other hemoglobinopathies¹⁸18. Szwarcwald CL, Malta DC, Pereira CA, Vieira MLFP, Conde WL, Souza Júnior PRB, et al. Pesquisa Nacional de Saúde no Brasil: concepção e metodologia de aplicação. Ciênc Saúde Coletiva 2014; 19(2): 333-42. http://dx.doi.org/10.1590/1413-81232014192.14072012
http://dx.doi.org/10.1590/1413-812320141... .

Information on hemoglobinopathy studies in the Brazilian population is important in order to know its epidemiological profile and establish a health care network, which allows genetic counseling and guidance to patients and their families.

The aim of this study was to describe the prevalence of hemoglobinopathies in the Brazilian adult population, according to sociodemographic characteristics, using laboratory tests from the PNS.

METHODS

The current study was a descriptive, epidemiological survey, and used data from PNS laboratory exams from 2014 to 2015.

The PNS is a nationwide household-based cross-sectional survey that uses three-stage probabilistic samples. The primary sampling units (PSUs) were the census tracts or set of tracts, the secondary units were the households, and the tertiary units were the adult residents, aged 18 years or older. Details on the sampling and weighting processes are provided in the publications on the PNS results¹⁸18. Szwarcwald CL, Malta DC, Pereira CA, Vieira MLFP, Conde WL, Souza Júnior PRB, et al. Pesquisa Nacional de Saúde no Brasil: concepção e metodologia de aplicação. Ciênc Saúde Coletiva 2014; 19(2): 333-42. http://dx.doi.org/10.1590/1413-81232014192.14072012
http://dx.doi.org/10.1590/1413-812320141... ^,1919. Souza-Júnior PRB, Freitas MPS, Antonaci GA, Szwarcwald CL. Desenho da amostra da Pesquisa Nacional de Saúde 2013. Epidemiol Serv Saúde 2015; 24(2): 207-16. http://dx.doi.org/10.5123/S1679-49742015000200003
http://dx.doi.org/10.5123/S1679-49742015... .

The sample consisted of 8,952 people. Post-stratification weights were used for sample weighting. Further details on laboratory data collection can be read in other publications¹⁸18. Szwarcwald CL, Malta DC, Pereira CA, Vieira MLFP, Conde WL, Souza Júnior PRB, et al. Pesquisa Nacional de Saúde no Brasil: concepção e metodologia de aplicação. Ciênc Saúde Coletiva 2014; 19(2): 333-42. http://dx.doi.org/10.1590/1413-81232014192.14072012
http://dx.doi.org/10.1590/1413-812320141... ^,1919. Souza-Júnior PRB, Freitas MPS, Antonaci GA, Szwarcwald CL. Desenho da amostra da Pesquisa Nacional de Saúde 2013. Epidemiol Serv Saúde 2015; 24(2): 207-16. http://dx.doi.org/10.5123/S1679-49742015000200003
http://dx.doi.org/10.5123/S1679-49742015... .

The research participants signed an informed consent form, and then peripheral blood was collected at any time of the day. The participant did not fast beforehand.

Hemoglobinopathies were investigated using the HPLC method. The results of the individual examinations were interpreted by providing the normal, homozygous or heterozygous parameters for HbS, HbC and HbD, as well as other possible hemoglobinopathies. Thalassemia and suspected thalassemia were presented together. The prevalence of hemoglobinopathies according to age, gender, education, skin color and region was described and analyzed. Bivariate analyses were performed using the Person χ² test, taking into account the sample weights. The analyses were performed with the aid of the statistical program Data Analysis and Statistical Software (Stata), version 14. The significance level considered was 5% (p < 0.05).

The PNS was approved by the National Research Ethics Commission (Comissão Nacional de Ética em Pesquisa - CONEP) of the National Health Council (Conselho Nacional de Saúde - CNS), of the Ministry of Health. Adult participation in the research was voluntary and confidentiality of their information was guaranteed.

RESULTS

A total of 8,952 tests were collected, and 237 results were excluded due to insufficient material, hemolysis, sample loss and other reasons, totaling 8,715 tests for analysis.

Hemoglobinopathies were present in 3.7% of the population (n = 327), and the following were found: sickle cell trait (2.49%), suspicion of major thalassemia (0.8%), minor thalassemia (0.3%), HbC carrier (0.04%) and probable carrier of persistent HbF (0.03%). When adding up minor thalassemia and suspected major thalassemia, the prevalence was 1.1% (Table 1).

Regarding the sickle cell trait and suspected major thalassemia according to sociodemographic characteristics, there was a statistically significant difference only for the skin color variable (p < 0.001). The prevalence found for sickle cell trait according to skin color was: 4.1% in dark-skinned black people; 3.6% in light-skinned black people; 1.2% in white people; and 1.7% among those who declared another skin color. The prevalence of suspected major thalassemia according to skin color was: 1.4% dark-skinned black people; 1.1% in light-skinned black people; and 0.3% in white people. The frequency of major hemoglobin abnormalities (sickle cell trait, minor thalassemia, and suspected major thalassemia) according to the categories of gender, age, education, and skin color are shown in Table 2.

Figure 1 shows the frequency of major hemoglobinopathies by skin color in the Brazilian regions. These included the sickle cell trait and the sum of minor thalassemia with suspected major thalassemia. The northeast and north regions show a higher frequency of dark-skinned and light-skinned black people, and the southeast and south regions show a higher frequency of white people. The northeast and the north regions tend to exhibit a higher prevalence of the sickle cell trait and the northeast region shows a higher prevalence of thalassemia, however there is no statistical significance (p> 0.05).

DISCUSSION

The results from the PNS laboratory identified 3.7% of the adult population with some type of hemoglobinopathy. The sickle cell trait and minor thalassemia (thalassemia minor or suspected thalassemia major) were the most frequent.

With regard to the sickle cell trait and thalassemia, the prevalence was more frequent in dark-skinned and light-skinned black people. In this research, α-thalassemia was not studied, as its investigation in clinical practice is rare and difficult to detect, since it is performed by gene sequencing¹⁰10. Forget BG, Bunn HF. Classification of the Disorders of Hemoglobin. Cold Spring Harb Perspect Med 2013; 3(2): a011684. http://doi.org/10.1101/cshperspect.a011684
http://doi.org/10.1101/cshperspect.a0116... . The prevalence of beta thalassemia is estimated to be low, with less than 1.5% of the Brazilian Caucasian population as carriers¹²12. Brasil. Ministério da Saúde. Orientações para diagnóstico e tratamento das Talassemias Beta [Internet]. Brasília: Ministério da Saúde ; 2016 [acessado em 9 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/orientacoes_diagnostico_tratamento_talassemias_beta.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... .

The sickle cell trait was the most frequent hemoglobinopathy in this research. It is worth noting that the presence of the sickle cell trait does not determine a disease and the carrier does not need treatment²⁰20. Brasil. Ministério da Saúde. Doença falciforme: o que se deve saber sobre herança genética [Internet]. Brasília: Ministério da Saúde ; 2014 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doenca_falciforme_deve_saber_sobre_heranca.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... . Nonetheless, its genetic condition should be taught, especially during the reproductive age²¹21. Brasil. Ministério da Saúde. Doença falciforme: diretrizes básicas da linha de cuidado [Internet]. Brasília: Ministério da Saúde ; 2015 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doenca_falciforme_diretrizes_basicas_linha_cuidado.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... ^,2222. Brasil. Ministério da Saúde. Doença falciforme: condutas básicas para tratamento [Internet]. Brasília: Ministério da Saúde ; 2012 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doenca_falciforme_condutas_basicas.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... . With regard to sickle cell anemia, in this study no case of a homozygote was found.

The first mutations in the hemoglobin molecule were described on the African continent and sickle cell disease is prevalent across Africa. Genetic mutations for thalassemia can especially be found in the Mediterranean populations, such as in the Portuguese, Italian, Greek, Arab, Syrian and Lebanese¹²12. Brasil. Ministério da Saúde. Orientações para diagnóstico e tratamento das Talassemias Beta [Internet]. Brasília: Ministério da Saúde ; 2016 [acessado em 9 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/orientacoes_diagnostico_tratamento_talassemias_beta.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... , yet the phenomena of population migration and miscegenation has provided for the heterogeneous distribution of hemoglobinopathies to most countries of the world²³23. Weatherall DJ. The inherited diseases of hemoglobin are an emerging global health burden. Blood 2010; 115(22): 4331-6. http://dx.doi.org/10.1182/blood-2010-01-251348
http://dx.doi.org/10.1182/blood-2010-01-... . The dispersion of genes for variant hemoglobin in Brazil is related to the process of colonization and migration²⁴24. Calvo-Gonzalez E. Hemoglobinas variantes na área médica e no discurso cotidiano: um olhar sobre raça, nação e genética no Brasil contemporâneo. Saúde Soc 2017; 26(1): 75-87. http://dx.doi.org/10.1590/s0104-12902017157821
http://dx.doi.org/10.1590/s0104-12902017... ^,2525. Melo-Reis PR, Naoum PC, Diniz-Filho FJA, Dias-Penna KGB, Mesquita MM, Balestra FA, et al. Prevalência de talassemias e hemoglobinas variantes no estado de Goiás, Brasil. J Bras Patol Med Lab 2006; 42(6): 425-30. http://dx.doi.org/10.1590/S1676-24442006000600004
http://dx.doi.org/10.1590/S1676-24442006... , as well as the miscegenation of black people from different African ethnic groups with the white population of Portuguese origin and, also, with the native indigenous population²⁶26. Brasil. Ministério da Saúde. Manual de doenças mais importantes, por razões étnicas, na população brasileira afro-descendente [Internet]. Brasília: Ministério da Saúde ; 2001 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doencas_etnicas.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... .

It was found in the study that the frequency of the sickle cell trait tended to be higher in the North and Northeast, which is justified because the population of light-skinned black people is more common in these regions, while dark-skinned black people are more present in the Northeast, especially in Bahia²⁷27. Instituto Brasileiro de Geografia e Estatística. Censo 2010 mostra as características da população brasileira [Internet]. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2015 [acessado em 1º fev. 2018]. Disponível em: Disponível em: http://www.brasil.gov.br/educacao/2012/07/censo-2010-mostra-as-diferencas-entre-caracteristicas-gerais-da-populacao-brasileira
http://www.brasil.gov.br/educacao/2012/0... . This finding coincides with the literature, which indicates a higher prevalence of sickle cell trait in the black population²⁶26. Brasil. Ministério da Saúde. Manual de doenças mais importantes, por razões étnicas, na população brasileira afro-descendente [Internet]. Brasília: Ministério da Saúde ; 2001 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doencas_etnicas.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... .

Previous research using PNTN data estimates that about 180,000 children/year with sickle cell trait are born²⁰20. Brasil. Ministério da Saúde. Doença falciforme: o que se deve saber sobre herança genética [Internet]. Brasília: Ministério da Saúde ; 2014 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doenca_falciforme_deve_saber_sobre_heranca.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... . According to state neonatal screening programs, the incidence of the sickle cell trait in live births in some states was: in Bahia, for each child with the sickle cell trait 17 did not have the trait, i.e. a 1:17 ratio; in Rio de Janeiro, 1:20; in Pernambuco and Maranhão, 1:23; in Goiás 1:25; in Espírito Santo, 1:28; in Minas Gerais, 1:30; in São Paulo 1:40; in Paraná, Rio Grande do Sul and Santa Catarina, 1:65²⁰20. Brasil. Ministério da Saúde. Doença falciforme: o que se deve saber sobre herança genética [Internet]. Brasília: Ministério da Saúde ; 2014 [acessado em 5 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/doenca_falciforme_deve_saber_sobre_heranca.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... . Thus, a greater presence of the sickle cell trait is confirmed in Bahia, the state with the largest black population²⁷27. Instituto Brasileiro de Geografia e Estatística. Censo 2010 mostra as características da população brasileira [Internet]. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2015 [acessado em 1º fev. 2018]. Disponível em: Disponível em: http://www.brasil.gov.br/educacao/2012/07/censo-2010-mostra-as-diferencas-entre-caracteristicas-gerais-da-populacao-brasileira
http://www.brasil.gov.br/educacao/2012/0... , as indicated in the present study.

It is important to emphasize that early diagnosis of hemoglobinopathies in the first week of life is essential to identify and ensure timely and continuous treatment and follow-up. Diagnoses are made by the State Neonatal Screening Programs (Programas Estaduais de Triagem Neonatal - PETN), which are regulated by the PNTN, and offered by the Public Health System (Sistema Único de Saúde - SUS)¹²12. Brasil. Ministério da Saúde. Orientações para diagnóstico e tratamento das Talassemias Beta [Internet]. Brasília: Ministério da Saúde ; 2016 [acessado em 9 dez. 2018]. Disponível em: Disponível em: http://bvsms.saude.gov.br/bvs/publicacoes/orientacoes_diagnostico_tratamento_talassemias_beta.pdf
http://bvsms.saude.gov.br/bvs/publicacoe... . In 2015, there was 85.79% SUS coverage for neonatal screening²⁸28. Brasil. Ministério da Saúde. Teste do Pezinho: atente-se ao prazo do exame e faça a diferença no futuro de nossas crianças [Internet]. Brasil: Ministério da Saúde; 2016 [acessado em 1º fev. 2018]. Disponível em: Disponível em: http://dab.saude.gov.br/portaldab/noticias.php?conteudo=_&cod=2241
http://dab.saude.gov.br/portaldab/notici... . By 2017, there were about 5.7 million newborns screened by the Minas Gerais Neonatal Screening Program and approximately 6,000 children/young people in follow-up and treatment for diagnosed diseases (May 2017 data)²⁹29. Núcleo de Ações e Pesquisa em Apoio Diagnóstico. Programa de Triagem Neonatal de Minas Gerais. Portal [Internet]. 2017 [acessado em 1º fev. 2018]. Disponível em: Disponível em: http://www.nupad.medicina.ufmg.br/programa-e-acoes/programa-de-triagem-neonatal-de-minas-gerais/
http://www.nupad.medicina.ufmg.br/progra... .

Given the findings, it is important to devote attention, investments and studies to better characterize and identify changes in hemoglobin in the Brazilian population, as well as to reduce morbidity and mortality, improve quality of life, and provide assistance to these people, families and society. In the adult carrier population, it is important to carry out genetic counseling before conception, due to the chances that the child might inherit sickle cell anemia and thalassemia.

CONCLUSION

This is the first study to determine the prevalence of hemoglobinopathies in adults in Brazil and its regions. The most prevalent hemoglobinopathies were the sickle cell trait, minor thalassemia and suspected major thalassemia. The sickle cell trait and thalassemia between dark- and light-skinned black people predominated. The Brazilian population is characterized by a miscegenation of a diversity of races, ethnicities, peoples, social and economic segments. The racial origin and the predominance of dark- and light-skinned black people as carriers of the sickle cell gene and the presence of the thalassemia genes are important aspects when considering hemoglobinopathies from the point of view of collective health and strategies for control.

ACKNOWLEDGMENTS

We would like to thank Dr. Jarbas Barbosa Silva Júnior and Gonzalo Vecina Neto, for their support in conducting the National Health Survey.

References

Publication Dates

History