Polymorphisms in the heme oxygenase-1 and bone morphogenetic protein receptor type 1b genes and estimated glomerular filtration rate in Brazilian sickle cell anemia patients

ABSTRACT Introduction Mutations affecting genes involved in oxidative and signaling pathways may be associated with kidney disease in sickle cell anemia. We determined the allele and genotype frequencies of some polymorphisms in the promoter regions of the Heme Oxygenase-1 (HMOX1) [rs2071746 (A > T) and (GT)n repeats, short (S) and long (L) alleles] and Bone Morphogenetic Protein Receptor type-1B (BMPR1B) [rs17022863 (A > G), rs4331783 (A > G) and rs1470409 (A > G)] genes in 75 adult patients with sickle cell anemia and 160 healthy controls and investigated whether these polymorphisms may influence the estimated glomerular filtration rate for the patients. Methods The single nucleotide polymorphisms were genotyped using the TaqMan assays, the HMOX1(GT)n repeats were determined by polymerase chain reaction fragment size analysis and the estimated glomerular filtration rate was calculated by the Modification of Diet in Renal Disease formula. Results Regarding the HMOX1rs2071746, the estimated glomerular filtration rate median was significantly higher in TT patients (p = 0.019), including when TT was compared with AT + AA (p = 0.009); for the (GT)n repeats, the estimated glomerular filtration rate medians of SS, SL and LL significantly differed (p = 0.009), being the LL estimated glomerular filtration rate median significantly higher, when compared with the LS + SS (p = 0.005). These results suggest that both the homozygotes, TT for rs2071746 and LL for (GT)n repeats, lead to a higher risk of developing renal complications. Concerning the BMPR1B, the frequencies of GG for rs17022863 and AA for rs4331783 were significantly higher in patients than in controls (p = 0.002 and p = 0.008, respectively), however no association with estimated glomerular filtration rate was found. Conclusion These results contribute to a better understanding of the genetic factors related to the development of nephropathy in sickle cell anemia patients.

Combined genotypes of the MBL2 gene related to low mannose-binding lectin levels are associated with vaso-occlusive events in children with sickle cell anemia

Abstract Sickle cell anemia (SCA) presents heterogenous clinical manifestations that cannot be explained solely by alterations to hemoglobin (Hb); other components such as endothelial adhesion, thrombosis and inflammation may be involved. The mannose-binding lectin (MBL) has an important role in innate immunity and inflammatory diseases. In this report, we describe an association between MBL2 polymorphism related to low production of serum MBL and the frequency of vasoocclusive events (FVOE) in children ≤ 5 years old with SCA (p = 0.0229; OR 5.55; CI 1.11-27.66). Further studies are needed to explore the role of low MBL2 in the pathophysiology of vasoocclusive events in SCA.

Follow-up of children with hemoglobinopathies diagnosed by the Brazilian Neonatal Screening Program in the State of Pernambuco

OBJECTIVE: To determine the geographical distribution of hemoglobinopathies in the State of Pernambuco, to characterize the children with these diseases and to describe factors associated with their follow-up at the referral center during the period from 2003 to 2010. METHODS: A retrospective, cross-sectional, descriptive study was carried out of 275 medical records from a total of 302 children with hemoglobinopathies diagnosed by the National Neonatal Screening Program in the State of Pernambuco in the study period. Microsoft Excel was used for data processing and analysis. The chi-square and the Fisher test were used for statistical analysis. The level of significance was set at 5%. Terra View software was used to analyze the geographical distribution of hemoglobinopathies in the State. RESULTS: A total of 8.9% of the cases of hemoglobinopathies detected in the period were not followed up at the referral center. For the mothers of children with diseases, this was their second or third or more pregnancy in 64.2% and 30.2%, respectively. Regarding the influence of region of residence and regular medical appointments, the study demonstrated that children from the Zona da Mata, Sertão and Vale do São Francisco regions did not attend 45.2%, 50% and 55.6% of their appointments in the outpatient department, respectively. CONCLUSIONS: This study shows that a significant number of children do not begin consultations in the outpatient clinic and even those who started treatment early and who have the most severe form of the disease, usually miss medical appointments...

Mannose-binding lectin 2 (MBL2) gene polymorphisms do not influence frequency of infections in chronic lymphocytic leukemia patients

Background: Infectious complications represent the main cause of morbidity and mortality in chronic lymphocytic leukemia. It has been reported that polymorphisms of the mannosebinding lectin 2 (MBL2) genes are correlated with MBL protein serum levels and, consequently, are associated with the development of infectious diseases. Objective: The purpose of this study was to investigate the possible association between MBL2 gene polymorphisms and risk of infection in chronic lymphocytic leukemia patients. Methods: Peripheral blood samples from 116 chronic lymphocytic leukemia patients were collected; after genomic DNA extraction, real time polymerase chain reaction was used to determine the polymorphisms of the promoter region and exon 1 of the MBL2 gene. Results: A high frequency of Binet stage A (p-value = 0.005) and absence of splenomegaly (p-value = 0.002) were observed in patients with no infection; however, variant alleles/ genotypes and haplotypes of this gene had no impact on the risk of infection. Conclusion: To the authors' knowledge, this is the first study describing the association between MBL2 polymorphisms and infectious disease in chronic lymphocytic leukemia. Although it was not possible to demonstrate any influence of MBL2 polymorphisms as a genetic modulator of infection in chronic lymphocytic leukemia, the authors believe that the present data are clinically relevant and provide the basis for future studies. .

Prevalência de dislipidemia em adultos de meia-idade com polimorfismo do gene NOS3 e baixa aptidão cardiorrespiratória / Prevalence of dyslipidemia in middle-aged adults with NOS3 gene polymorphism and low cardiorespiratory fitness

OBJETIVO: Analisar a influência da associação dos polimorfismos do gene da sintase do óxido nítrico endotelial (NOS3) para as posições -786T>C, Glu298Asp e íntron 4b/a e a aptidão cardiorrespiratória sobre as concentrações de nitrito/nitrato, pressão arterial, perfil lipídico e prevalência de doenças cardiometabólicas em adultos. SUJEITOS E MÉTODOS: Noventa e duas pessoas foram divididas de acordo com o genótipo: não polimórficas (NP) e polimórficas (P). Posteriormente, foram subdivididas pela aptidão cardiorrespiratória associada ao genótipo: alta (ANP e AP) ou baixa (BNP e BP). RESULTADOS: Os indivíduos que apresentavam polimorfismo para as posições Glu298Asp+Íntron 4b/a e Glu298Asp+-786T>C e baixa aptidão cardiorrespiratória apresentaram maiores valores de colesterol total e maior prevalência de dislipidemia. CONCLUSÃO: Nossos dados demonstram que os polimorfismos do gene da NOS3 para essas duas associações influenciam os níveis de colesterol plasmático, e essa associação foi mais claramente observada quando os indivíduos apresentavam menor nível de aptidão cardiorrespiratória.

OBJECTIVE: To evaluate the influence of the interaction between endothelial nitric oxide synthase gene (NOS3) polymorphisms at positions -786T>C, Glu298Asp and intron 4b/a, and cardiorespiratory fitness on plasma nitrite/nitrate levels, blood pressure, lipid profile, and prevalence of cardiometabolic disorders. SUBJECTS AND METHODS: Ninety-two volunteers were genotyped for NOS3 polymorphisms at positions (-786T>C and Glu298Asp) and (intron 4b/a) and divided according to the genotype: non-polymorphic (NP) and polymorphic (P). After that, they were subdivided according to the cardiorespiratory fitness associated with genotype: high (HNP and HP) and low (LNP and LP). RESULTS: The subjects with polymorphism for the interactions at positions Glu298Asp + intron 4b/a, and Glu298Asp+-786T>C showed the highest values in total cholesterol, as well as dyslipidemia. CONCLUSION: Our findings show that NOS3 gene polymorphisms at positions -786T>C, Glu298Asp, and intron 4b/a exert negative effects on the lipid profile compared with those who do not carry polymorphisms.

Triagem familiar para o gene HBB*S e detecção de novos casos de traço falciforme em Pernambuco / Family screening for HBB*S gene and detection of new cases of sickle cell trait in Northeastern Brazil

OBJETIVO: Estimar o incremento no número adicional de afetados com base na prevalência de síndromes falciformes em familiares de casos-índice. MÉTODOS: Estudo transversal em familiares de amostra aleatória dos casos-índice identificados por programa de triagem neonatal em Pernambuco, no período de 2001 a 2005. O modelo de triagem familiar ampliado incluiu 463 membros familiares de 21 casos-índice. Os familiares foram categorizados como: núcleo reduzido (NR -pai, mãe e irmãos); de primeiro grau (N1 - avós, tios e primos de primeiro grau); de segundo grau (N2 - filhos dos primos de primeiro grau); ampliado (NA - NR+N1+N2) e ampliado de primeiro grau (NA1 -NR+N1). A confirmação da presença de HBB*S e detecção de hemoglobinas anormais foram realizadas por meio da High Performance Liquid Chromathgraphy. A associação entre a presença de HBB*S e variáveis foi testada pelo cálculo da razão de prevalência e respectivos IC 95 por cento e a diferença entre médias verificadas pelo teste t de Student, ao nível de significância de 5 por cento. RESULTADOS: A anemia falciforme era desconhecida por 81 por cento dos familiares; o gene HBB*S esteve presente em 114 familiares. Observou-se que 53,3 por cento da população estudada estava na faixa considerada reprodutiva e 80 por cento das pessoas portadoras do gene HBB*S já tinham gerado filhos. A freqüência foi maior no núcleo NR (69 por cento), mas também elevada no N1 (22,8 por cento). O NA1 resultou na detecção de 69 portadores adicionais (aumento de 172 por cento). CONCLUSÕES: Os resultados indicam que a triagem familiar para identificação de portadores de síndrome falciforme deve ser estendida para os familiares até o primeiro grau.

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 percent confidence intervals, and differences between means were calculated using Student's t test with a 5 percent significance level. RESULTS: Of relatives, 81 percent had no knowledge of sickle-cell anemia and HBB*S was present in 114 family members. A total of 53.3 percent of the studied population was considered as of reproductive age, and 80 percent of HBB*S carriers had already had children. Frequency was higher among NF (69 percent), but was also high in N1 (22.8 percent). NA1 screening resulted in the detection of 69 carriers additional (a 172 percent increase). CONCLUSIONS: These results indicate that family screening for the identification of sickle-cell carriers should be extended to first degree relatives.