Association of FOXO3 polymorphism (rs3800231) and clinical subphenotypes of beta thalassemic individuals

Abstract Introduction Studies have shown that the loss of the FOXO3 transcriptional function is involved in the pathophysiology of some chronic erythroid disorders, including beta-thalassemia (β-thal). Therefore, the single nucleotide polymorphism (SNP) rs3800231 (35-2764A > G) could contribute to alterations in its transcriptional activity, acting as a modifier of β-thal phenotypic manifestations. Objective and method In order to better understand the genotypic and/or allelic distributions among β-thal patients, we evaluated 83 β-thal heterozygous and 20 homozygous, compared to 117 individuals without hemoglobinopathies (control group). Additionally, we verified any influence of the FOXO3 polymorphism on clinical manifestations among β-thal homozygotes. Results We obtained higher frequencies of the wild-type homozygous (AA) and the wild-type allele (A) in the β-thal group (p< 0.0001 and p= 0.00014, respectively). The most common clinical manifestations found among β-thal homozygotes were iron overload (90%), splenomegaly (65%) and bone complications (35%), e.g., osteopenia/osteoporosis. We observed that close to 80% of the patients presenting such manifestations had the genotype AA. However, we did not find any significant involvement of the FOXO3 polymorphism in clinical manifestation occurrences. Conclusion Thus, we concluded that the SNP rs3800231 did not play a significant role as a modifier of the clinical manifestations observed in the β-thal homozygotes studied.

A interação entre Hb B2, Hb S e beta talassemia: um relato de caso familiar

As hemoglobinopatias são doenças hereditárias que incluem talassemia e doença falciforme. O objetivo do presente estudo foi destacar a interação entre a variante Hb S, formas talassêmicas (beta talassemia por IVS1-6) e a variante Hb B2. Os exames realizados foram hemograma completo, eletroforese de hemoglobina em pH ácido e alcalino, dosagem de hemoglobina A2, Cromatografia Líquida de Alta Performance e investigação molecular. Esse relato evidencia a interação entre os polimorfismos de hemoglobina na população brasileira e a necessidade de adequada interpretação dos resultados de testes clássicos para a melhor compreensão dos casos.

Hemoglobinopathies are a hereditary disease that includes thalassemia and sickle cell disease. The present study aimed to show the interaction between the Hb S variant, thalassemia forms (Beta-thalassemia by IVS1-6), and the Hb B2 variant. The tests performed were complete blood count, hemoglobin electrophoresis at acid and alkaline pH, hemoglobin A2 dosage, High-Performance Liquid Chromatography, and molecular investigation. This report highlights the interaction between hemoglobin polymorphisms in the Brazilian population and the need for an adequate interpretation of the results of classical tests for a better understanding of the cases.

Association of HMIP1 C-893A polymorphism and disease severity in patients with sickle cell anemia

Abstract Introduction: Sickle cell anemia (SCA) is a Mendelian disorder with a heterogeneous clinical course. The reasons for this phenotypic diversity are not entirely established, but it is known that high fetal hemoglobin levels lead to a milder course of the disease. Additionally, genetic variants in the intergenic region HBS1L-MYB promote high levels of fetal hemoglobin into adulthood. Objective: In the present study, we investigated the HMIP1 C-839A (rs9376092) polymorphism, located at the HBS1L-MYB intergenic region block 1, in SCA patients. Method: We analyzed 299 SCA patients followed in two reference centers in Brazil. The HMIP1 C-839A (rs9376092) genotypes were determined by allele specific polymerase chain reactions. Clinical and laboratory data were obtained from patient interviews and medical records. Results: The median fetal hemoglobin levels were higher in patients with the HMIP1 C-839A (rs9376092) AA genotype (CC = 6.4%, CA = 5.6% and AA = 8.6%), but this difference did not reach significance (p = 0.194). No association between HMIP1 C-839A (rs9376092) genotypes and other clinical and laboratorial features was detected (p > 0.05). Conclusion: In summary, our data could not support the previously related association between the HMIP1 C-893A (rs9376092) polymorphism and differential fetal hemoglobin levels.

Rastreamento de hemoglobinas variantes e talassemias com associação de métodos de diagnóstico / Tracking of variant hemoglobins and thalassemias by association of diagnosis methodologies

O diagnóstico neonatal de hemoglobinopatias permite a melhoria na qualidade de vida do doente com a implementação de medidas profiláticas, acompanhamento clínico e aconselhamento genético. Objetivou-se no presente estudo o diagnóstico das hemoglobinas variantes e talassemias em amostras de sangue de cordão umbilical de neonatos da região noroeste do estado de São Paulo por Cromatografia Líquida de Alta Performance (HPLC), associada a procedimentos eletroforéticos, bioquímicos e citológicos, visando adaptar a melhor metodologia de análise à freqüência dos defeitos de hemoglobina na população brasileira. Foram analisadas 3.048 amostras de janeiro de 2001 a dezembro de 2002, e 13,12 por cento apresentaram alterações de hemoglobinas, sendo 1,84 por cento com presença de Hb S; 0,6 por cento com Hb C; 0,65 por cento com resultados sugestivos de beta talassemia e 9,48 por cento sugestivos de alfa talassemia. Dentre as hemoglobinas anormais encontradas, 0,33 por cento das amostras apresentaram resultados discordantes nas metodologias aplicadas. A HPLC mostrou-se eficiente para a identificação de variantes de hemoglobinas e permitiu a análise de grande número de amostras em curto espaço de tempo e agilidade nas triagens. Entretanto, foi necessário associar outros métodos de análise para a caracterização das formas talassêmicas.

The neonatal diagnosis hemoglobinopathies improves the quality of life by prophylactic measures and genetic counseling. The diagnosis of variant hemoglobins and thalassemias was considered in the present study. Cord blood samples of newborn babies from the northwestern region of São Paulo state were analyzed by High Performance Liquid Chromatography (HPLC) associated with electrophoretic, biochemical and cytologic procedures aiming to adapt the best methodology to analyze the frequency of hemoglobin defects in the Brazilian population. Three thousand and forty-eight samples were analyzed from January 2001 to December 2002 with 13.12 percent presenting hemoglobin alterations; 1.84 percent had Hb S; 0.6 percent had Hb C; 0.65 percent were suggestive of thalassemia beta and 9.48 percent were suggestive of thalassemia alpha. Among the abnormal hemoglobins, 0.33 percent of the samples presented different results in the methodologies used. HPLC was efficient to identify variant hemoglobins and enable the analysis of several samples in a short period of time with agility in screenin. However, an association of other methods was necessary for the characterization of the thalassemic forms.