Talassemias alfa e beta: revisão

Abstract

The human hemoglobins are proteins that are both studied and known genet ically. The genet ic systems, which part icipate in the human hemoglobin’s syntheses, are located in the 16 and 11 chromosomes. Each one of them has the groupings of alpha and beta genes. Each one of these groupings has genes that act specifically in the embryonic and fetal phases and soon after the birth.The group of clinical symptoms and laboratory alterations result ing from mutat ions that affected the quant itative synthesis in the product ion of normal globins chains was named Thalassaemia. It const itutes a heterogeneous group of genet ic diseases, which are characterized by the lack or reduct ion of the hemoglobin production. It occurs an imbalance between the alpha and beta globins because of the alpha or beta globins decrease. The clinical manifestat ions can vary from serious hereditary anemia incompat ible with life (e.g. major thalassaemia) to the intermediary thalassaemia and even benign forms pract ically without symptoms as, for example, the heterozygous. However, it can be detected by laboratory exams. The most serious symptomat ic forms are characterized by hemolyt ic anemia and they cause weakness, jaundice, esplenomegaly, erythroid hyperplasia of the bone medulla, hepatomegaly, retard of the somat ic and sexual development and hypocromic forms. The blood transfusions are necessary for the treatment of serious thalassaemia, but they cause an excessive accumulat ion of iron in the body due to periodic transfusions. So, it should be made the iron break by a drug called deferoxamin (DFO). This drug reduces the iron excess in the organism as well as the morbidity and mortality of the pat ients. The distribut ion of thalassaemia in Brazil is related to the races that compose our populat ion.