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Hemoglobinopatias e talassemias
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As alterações estruturais na hemoglobina, conhecidas como hemoglobinopatias, são normalmente causadas pela substituição de um único aminoácido de uma cadeia globínica. Embora a maioria seja de importância clínica limitada, alguns subtipos importantes foram identificados com alguma frequência. Homozigotos Hb C e Hb S (anemia falciforme) produzem manifestações clínicas significativas, enquanto que homozigotos Hb D E Hb E podem ser levemente sintomáticos. O diagnóstico genético é assim essencial. As talassemias, em contraste, são resultado das reduções quantitativas na síntese da cadeia de globina. Os indivíduos com diminuição de cadeias p-globina sofrem de p-talassemias, enquanto aqueles com diminuição da produção de cadeia a apresentam a-talassemias. As menores síndromes talassémicas são caracterizadas clinicamente por anemia leve com microcitose persistente. As principais talassemias provocam anemia grave, com risco de vida. A a-talassemia major geralmente é incompatível com a vida extra-uterina. Estas condições patológicas requerem muitas vezes tratamento ao longo da vida, transfusão e/ou transplante de medula óssea para o sucesso do controle da doença. Vários trabalhos foram publicados que descrevem as etapas necessárias para a investigação das hemoglobinopatias e talassemia.
Structural changes in hemoglobin are usually a single substitution of an amino acid of a globin chain. Although most are of limited clinical importance, few important subtypes have been identified with some frequency. Homozygous Hb C and Hb S (sickle cell anemia) produce significant clinical manifestations, whereas homozygous Hb A Hb E may be mildly symptomatic. Genetic diagnosis is therefore essential. The thalassemias, in contrast, are the result of quantitative reductions in globin chain synthesis. Those with decreased 0-globin chains are suffering from 13-thalassemia, while those with decreased production of a chain a-thalassemia present minors thalassemic syndromes, characterized clinically by mild anemia with persistent microcytosis. Thalassemia major causes severe anemia, life-threatening. a-Thalassemia major is usually incompatible with life outside the womb. These pathological conditions often require lifelong treatment transfusion and / or bone marrow transplantation for successful disease control. Several guidelines have been published that describe the steps necessary for the investigation of hemoglobinopathies and thalassemias.
Structural changes in hemoglobin are usually a single substitution of an amino acid of a globin chain. Although most are of limited clinical importance, few important subtypes have been identified with some frequency. Homozygous Hb C and Hb S (sickle cell anemia) produce significant clinical manifestations, whereas homozygous Hb A Hb E may be mildly symptomatic. Genetic diagnosis is therefore essential. The thalassemias, in contrast, are the result of quantitative reductions in globin chain synthesis. Those with decreased 0-globin chains are suffering from 13-thalassemia, while those with decreased production of a chain a-thalassemia present minors thalassemic syndromes, characterized clinically by mild anemia with persistent microcytosis. Thalassemia major causes severe anemia, life-threatening. a-Thalassemia major is usually incompatible with life outside the womb. These pathological conditions often require lifelong treatment transfusion and / or bone marrow transplantation for successful disease control. Several guidelines have been published that describe the steps necessary for the investigation of hemoglobinopathies and thalassemias.