Flavia Miranda Gomes de Constantino Bandeira

Molecular Variations Linked to the Grouping of β- and α-Globin Genes in Neonatal Patients with Sickle Cell Disease in the State of Pernambuco, Brazil

Various factors have been described as phenotypic modulators of sickle cell disease, such as levels of fetal hemoglobin (Hb F), presence of α-thalassemia (thal), and haplotypes of the β-globin genes. In order to characterize and determine the frequency of the βS and βC mutations and the prevalence of −α3.7-thal, 74 patients with sickle cell disease detected during neonatal screening in the State of Pernambuco, Brazil, were studied. The haplotypes of the β gene and −α3.7-thal were determined using polymerase chain reaction (PCR), and specific restriction endonucleases were used to establish the polymorphic sites of the haplotypes. The results showed the high frequency of the Central African Republic (CAR) or Bantu haplotype in the State of Pernambuco, Brazil. The low frequency of the Benin haplotype recorded in this study, in comparison with other states in northeast Brazil, suggests the diversity of origins of Afro-Brazilians in this region.

Triagem familiar para o gene HBB*S e detecção de novos casos de traço falciforme em Pernambuco

OBJECTIVE To estimate the additional number of affected individuals based on the prevalence of sickle-cell syndromes among relatives of index cases. METHODS Cross-sectional study of relatives of a random sample of index cases identified through a neonatal screening program in Northeastern Brazil, between 2001 and 2005. The extended family trial model included 463 relatives of 21 index cases. Relatives were classified as nuclear family (NF: father, mother, and siblings); first degree extended family (N1: grandparents, uncles and aunts, and first cousins); second degree extended family (N2: children of first cousins); extended family (NA: NF+N1+N2); and extended nuclear family (NA1: NF+N1). The presence of HBB*S and other abnormal hemoglobins was confirmed by high-performance liquid chromatography. The association between the presence of HBB*S and other variables was calculated using prevalence ratios and their respective 95% confidence intervals, and differences between means were calculated using Students t test with a 5% significance level. RESULTS Of relatives, 81% had no knowledge of sickle-cell anemia and HBB*S was present in 114 family members. A total of 53.3% of the studied population was considered as of reproductive age, and 80% of HBB*S carriers had already had children. Frequency was higher among NF (69%), but was also high in N1 (22.8%). NA1 screening resulted in the detection of 69 carriers additional (a 172% increase). CONCLUSIONS These results indicate that family screening for the identification of sickle-cell carriers should be extended to first degree relatives.OBJECTIVE: To estimate the additional number of affected individuals based on the prevalence of sickle-cell syndromes among relatives of index cases. METHODS: Cross-sectional study of relatives of a random sample of index cases identified through a neonatal screening program in Northeastern Brazil, between 2001 and 2005. The extended family trial model included 463 relatives of 21 index cases. Relatives were classified as nuclear family (NF: father, mother, and siblings); first degree extended family (N1: grandparents, uncles and aunts, and first cousins); second degree extended family (N2: children of first cousins); extended family (NA: NF+N1+N2); and extended nuclear family (NA1: NF+N1). The presence of HBB*S and other abnormal hemoglobins was confirmed by high-performance liquid chromatography. The association between the presence of HBB*S and other variables was calculated using prevalence ratios and their respective 95% confidence intervals, and differences between means were calculated using Students t test with a 5% significance level. RESULTS: Of relatives, 81% had no knowledge of sickle-cell anemia and HBB*S was present in 114 family members. A total of 53.3% of the studied population was considered as of reproductive age, and 80% of HBB*S carriers had already had children. Frequency was higher among NF (69%), but was also high in N1 (22.8%). NA1 screening resulted in the detection of 69 carriers additional (a 172% increase). CONCLUSIONS: These results indicate that family screening for the identification of sickle-cell carriers should be extended to first degree relatives.

Hidroxiuréia em pacientes com síndromes falciformes acompanhados no Hospital Hemope, Recife, Brasil

The use of hydroxyurea increases concentrations of fetal hemoglobin (Hb F) in sickle cell disease patients. It has been used in adults and in trials with children with the aim of preventing events such as episodes of pain or stokes. The objective of this study was to analyze the efficacy and side effects of Hydroxyurea in children with ages ranging from 5 to 17 years and also in young adults with SS or Sβ0 hemoglobinopathies. The patients were treated in the outpatient clinic of the Hemope Hospital. Young patients were treated with hydroxyurea at 10 mg/kg/day which was increased by 5 mg/kg/day at 8-week intervals until reaching a maximum dose of 25 mg/kg/day. For adults, the treatment started at 500 mg/day and increased until a dose of 1000 mg/day was reached. Total Hb F levels and the Mean Corpuscular Volume rose with hydroxyurea therapy and there was a reduction of events involving pain as well as the necessity of hospitalization among the pediatric patients. With the over 18year-old patients, a better clinical state was noticed together with a rise in hemoglobin levels and a reduction in the reticulocyte, leukocyte and platelet counts. No signs or symptoms in respect to drug toxicity were evidenced in either group. The use of hydroxyurea seems to be safe and effective in both children and young adults with sickle cell disease. The drug also improves theO uso de hidroxiureia promove a elevacao dos niveis de hemoglobina fetal (Hb F) em pacientes portadores de sindromes falciformes (SF) e o medicamento vem sendo estudado em varios grupos de pacientes, incluindo adultos e criancas. O presente trabalho analisou a eficacia e tolerabilidade do uso de hidroxiureia em criancas na faixa etaria entre 5 e 17 anos de idade e em adultos jovens acima de 18 anos, portadores de hemoglobinopatia SS ou Sb0 que foram acompanhados regularmente no ambulatorio do Hospital Hemope. Os pacientes pediatricos foram tratados com dose inicial de hidroxiureia de 10 mg/kg/dia, a qual era aumentada em 5 mg/kg por dia em intervalos de oito semanas, ate a dose maxima de 25 mg/kg/dia. Para os adultos, o tratamento foi iniciado com 500 mg/dia de hidroxiureia ate a dose maxima de 1g/dia. Foi observada reducao do numero de crises algicas assim como do numero de internacoes hospitalares, elevacao do nivel de Hb F e do Volume Corpuscular Medio, no grupo pediatrico. Entre os pacientes maiores de 18 anos, tambem se observou melhora clinica e significância estatistica com aumento dos valores da hemoglobina e reducao dos valores de reticulocitos, leucocitos e plaquetas. Nao foram observados sinais ou sintomas sugestivos de toxicidade medicamentosa em ambos os grupos. O uso de hidroxiureia em todos os pacientes parece ser seguro e eficaz e assegura melhora da qualidade de vida e beneficios a seus familiares. Ademais, as doses preconizadas de hidroxiureia aparentemente nao foram mielotoxicas, nao tendo sido necessaria a suspensao do tratamento em nenhum dos pacientes.

Importância dos programas de triagem para o gene da hemoglobina S

Sickle cell anemia is a hereditary condition that evolves to a chronic illness, causing physical and emotional disorders to those involved. As yet there is no cure except for bone marrow transplantation which is still in the experimental stage. Neonatal screening for hemoglobin disorders, particularly sickle cell anemia, has been crucial for ensuring early diagnosis and the application of preventive and health-promoting measures. The Brazilian Health Ministry recommends testing parents thereby identifying heterozygotes, but does not propose extending this screening to other family members. A family that has a child affected by one of these syndromes is a marker for an at-risk group. In this case extending screning to close relatives (grandparents, siblings, aunts and uncles, and cousins) may identify individuals affected by the disease or couples at risk before marriage and reproduction and serve as the basis for programs providing genetic evaluation and epidemiological control of hemoglobin diseases that are relatively common in the Brazilian population.

Diagnóstico da hemoglobina S: análise comparativa do teste de solubilidade com a eletroforese em pH alcalino e ácido no período neonatal

OBJECTIVES: to evaluate the efficacy of the solubility test as a screening method for hemoglobin S detection in newborns compared to alkaline and acid hemoglobin electrophoresis . METHODS: a total of 1.988 cord blood samples from newborns at Instituto Materno Infantil de Pernambuco (IMIP) during the period of October 1996 to March 1997 were submitted to alkaline hemoglobin electrophoresis and solubility test. Following this, acid hemoglobin electrophoresis was performed as a confirmatory test, when Hb S was present in the first two tests mentioned. RESULTS: Hb S was detected in 105 (5,3%) of the 1.988 samples by alkaline electrophoresis and were confirmed by acid electrophoresis in 98 (93,3%). Solubility test has detected Hb S in only one sample. CONCLUSIONS: alkaline hemoglobin electrophoresis has been effective for Hb S screening in newborn period and can be used in places where more sophisticated techniques are not available. Solubility test must not be used as a screening method in this period of life.

Saúde pública e ética na era da medicina genômica: rastreamentos genéticos

This article has the objective to bring the field of public health into context in the face of the great advances of biotechnology and applied genetics, focusing on issues related to the theme such as benefits and ethics concerning genetic screening. The Human Genome Project has generated many expectations among which the possibility of screening genes associated to diseases and behaviors, moreover, the possibility of genetic interventions on humans, creating concerns related to the resurgence of Eugenia, of genetic counseling and the use of genetic information as a standard for access to healthcare clinics and jobs. The discussion of all these issues is essential to benefit public health with information obtained through population genomic analysis.

Triagem familiar ampliada para o gene da hemoglobina S

Objetivou-se determinar a prevalencia de sindromes falciformes em familiares selecionados a partir de casos indice, com particular interesse em determinar o numero de afetados adicionais detectados pelo modelo de triagem familiar ampliado. Utilizou-se um estudo de corte transversal de base populacional, realizado em familiares dos casos-indice identificados pela triagem neonatal no Recife, regiao metropolitana do Recife e em algumas cidades do interior do estado de Pernambuco. Foram estudados os membros familiares dos casos-indice recrutados a partir da listagem fornecida pelo Programa de Triagem Neonatal de Pernambuco alocados em nucleos definidos como: 1) nucleo reduzido (NR): constituido de pai, mae e irmaos; 2) nucleo de primeiro grau (N1): constituido de avos, tios e primos de primeiro grau; 3) nucleo de segundo grau (N2): filhos dos primos de primeiro grau; 4) nucleo ampliado (NA): NR+N1+N2 e 5) nucleo ampliado de primeiro grau (NA1): NR+N1. Foram coletadas de agosto de 2004 a junho de 2005, informacoes e amostras de sangue periferico de 463 membros familiares pertencentes a 21 casos-indice. A mediana de idade foi de 22 anos onde 81,5 por cento desconheciam o que era anemia falciforme. Destes, 90,5 por cento eram do Recife e regiao metropolitana. O gene HBB*S esteve presente em 114 individuos. A frequencia deste gene foi maior no NR (69 por cento), mas tambem elevada no N1 (22,8 por cento). De fato, o NA1 resultou na deteccao de 69 portadores adicionais (cerca de 172 por cento de casos adicionais). Tambem ocorreu um incremento de 73 por cento na media comparando o NR com o N1. Esses resultados indicam que um numero relevante de individuos portadores do gene HBB*S seria detectado com a ampliacao do NR atraves da inclusao do N1. Observou-se que 53,3 por cento da populacao estudada, estava na faixa considerada reprodutiva e 80 por cento das pessoas que carregavam o gene HBB*S ja tinham gerado filhos. Os resultados permitem as seguintes recomendacoes: 1) A triagem para hemoglobinopatias deve permanecer de maneira universal no estado de Pernambuco. 2) A triagem familiar ampliada, para identificacao de portadores de sindrome falciforme deve ser estendida para os familiares ate o primeiro grau. 3) E recomendavel que acoes educativas sobre as sindromes falciformes ocorram de forma sistematica em Pernambuco. 4) E necessario o envolvimento dos atores do sistema de atencao basica a saude no tocante a multiplicacao do conhecimento sobre estas sindromes.