Avaliação da expressão da talassemia Beta no Brasil pela coherança com defeitos de hemocromatose
Data
2003-02-19
Autores
Carvalho, Lya Bueno [UNESP]
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ISSN da Revista
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A talassemia beta constitui um grupo heterogêneo de distúrbios genéticos da síntese de hemoglobina sendo uma das doenças monogênicas mais comums, identificada e estudada por várias décadas. É originária da região do Mediterrâneo porém, atualmente apresenta-se amplamente distribuída pelo mundo devido ao fluxo gênico pela migração das populações. No Brasil, os tipos de talassemia mais prevalentes são as talassemias alfa e beta e apresentam número variável de indivíduos portadores devido ao alto grau de miscigenação da população. As formas graves de talassemia beta são facilmente diagnosticadas entretanto, as formas mais suaves muitas vezes são interpretadas e tratadas como anemia ferropriva. O presente estudo teve como objetivo caracterizar as formas talassêmicas do tipo beta e verificar os interferentes na expressão do fenótipo como a possível co-herança com hemocromatose hereditária. Através da associação de análise hematimétrica, metodologias clássicas e análise por HPLC analisamos 332 amostras de sangue com suspeita de talassemia beta. Um total de 70 amostras foram identificadas como portadores de hemoglobinas normais (AA), 145 portadores de talassemia beta heterozigota (BTH) e 117 portadores de talassemia alfa/beta (ABT). A análise estatística por regressão linear entre as metodologias clássicas e HPLC para quantificação de hemoglobina A2 e Fetal para os três grupos foram estatisticamente significativas. A análise molecular por PCR-ASO para identificação dos mutantes para hemocromatose hereditária mostraram 11,76% de mutação C282Y e 70,58% para H63D no grupo de talassemia beta e 25% de mutação C282Y e 75% H63D para o grupo de talassemia alfa/beta. Esses resultados evidenciam a necessidade da associação de metodologias para o correto diagnóstico da talassemia beta, bem como caracterização molecular para hemocromatose...
The beta-thalassemia constitutes a heterogeneous group of genetic disorders of hemoglobin synthesis. It has been one of the most common monogenic diseases identified and studied for many decades. Its origins are from Mediterranean region, although nowadays it is spread for the whole world due to gene flow of migration populations. In Brazil, the most prevalent types of thalassemia are the alpha-thalassemia and beta-thalassemia. They present a variable number of individual carriers due to high degree of miscigenation. The serious forms of beta-thalassemia are easily identified, but the milder forms are many times diagnosed and treated as iron deficiency anemia. The objective of the present study was to characterize the thalassemic forms and verify the interferents in the expression of the phenotype as the possible co-inheritance with hereditary hemochromatosis. It was analysed, utilizing hematimetric analysis, classic methodologies and HPLC analysis, 332 blood samples suspect of beta-thalessemia. The total of 70 samples were identified as carriers of normal hemoglobins (AA), 145 carriers of beta-thalassemia heterozigote (BTH) and 117 carriers of alpha/beta-thalassemia (ABT). The statistic analysis by linear regression between classic methodologies and HPLC for quantification of hemoglobin A2 and Fetal hemoglobin were statistically differents and significants. The molecular analysis by PCR-ASO to identify the mutants with hereditary hemochromatosis showed 11,76% of mutation C282Y and 70,58% to H63D in the beta-thalassemia group and 25% of mutation C282Y and 75% of H63D in the alpha/beta- thalassemia group. These results prove the necessity of association of methodologies in order to achieve the correct diagnosis of beta-thalassemia, as well as the molecular characterization of hemochromatosis, due to the fact of its possible co-inheritance with beta-thalassemia in the vast genotypic diversity found in Brazil.
The beta-thalassemia constitutes a heterogeneous group of genetic disorders of hemoglobin synthesis. It has been one of the most common monogenic diseases identified and studied for many decades. Its origins are from Mediterranean region, although nowadays it is spread for the whole world due to gene flow of migration populations. In Brazil, the most prevalent types of thalassemia are the alpha-thalassemia and beta-thalassemia. They present a variable number of individual carriers due to high degree of miscigenation. The serious forms of beta-thalassemia are easily identified, but the milder forms are many times diagnosed and treated as iron deficiency anemia. The objective of the present study was to characterize the thalassemic forms and verify the interferents in the expression of the phenotype as the possible co-inheritance with hereditary hemochromatosis. It was analysed, utilizing hematimetric analysis, classic methodologies and HPLC analysis, 332 blood samples suspect of beta-thalessemia. The total of 70 samples were identified as carriers of normal hemoglobins (AA), 145 carriers of beta-thalassemia heterozigote (BTH) and 117 carriers of alpha/beta-thalassemia (ABT). The statistic analysis by linear regression between classic methodologies and HPLC for quantification of hemoglobin A2 and Fetal hemoglobin were statistically differents and significants. The molecular analysis by PCR-ASO to identify the mutants with hereditary hemochromatosis showed 11,76% of mutation C282Y and 70,58% to H63D in the beta-thalassemia group and 25% of mutation C282Y and 75% of H63D in the alpha/beta- thalassemia group. These results prove the necessity of association of methodologies in order to achieve the correct diagnosis of beta-thalassemia, as well as the molecular characterization of hemochromatosis, due to the fact of its possible co-inheritance with beta-thalassemia in the vast genotypic diversity found in Brazil.
Descrição
Palavras-chave
Beta-thalassemia, Hemoglobinopathies, Hemochromatosis, Talassemia, Anemia, Talassemia beta, Anemia hereditária, Hemocromatose hereditária
Como citar
CARVALHO, Lya Bueno. Avaliação da expressão da talassemia Beta no Brasil pela coherança com defeitos de hemocromatose. 2003. 121 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2003.