HA. Pearson, Current Trends in the Management of Homozygous ß-Thalassemia. 1996; 16(5): 554-558 ß-thalassemia is a genetic disease associated with decreased production of the ß-polypeptide chains of human hemoglobin. More than 100 different mutations have been identified that produce the thalassemia phenotype. Persons with the heterozygous state, thalassemia trait, have a mild microcytic anemia, with hemoglobin levels 1 to 2 g/dL below appropriate age and gender normal levels. Individuals with thalassemia trait usually have no symptoms. In contrast, homozygosity for thalassemia genes usually results in thalassemia major (TM) or Cooley's anemia, a severe, transfusion-dependent hemolytic anemia.The management of TM has undergone significant changes over the last two decades. This review will outline the management of these patients, the therapeutic considerations currently available and possible future interventions.The lifelong management of patients with TM involves several decision points and considerations: 1) The criteria for initiating transfusions. 2) The transfusion regimen: the blood product to be used, frequency of transfusions, and desired levels of hemoglobin to be maintained. 3) The criteria for performing splenectomy and the management of postsplenectomy complications. 4) The criteria for initiating chelation therapy with deferoxamine (DF) and the regimen to be used. 5) The periodic evaluation of DF therapy. 6) Results of modern transfusion and chelation therapy. 7) The status of oral iron chelating agents. 8) Prenatal diagnosis. 9) Bone marrow transplantation. 10) Pharmacological treatment. 11) The prospects for gene therapy.
Criteria for TransfusionsAlmost all patients with TM require blood transfusion within the first two to three years of life to prevent severe anemia and its physical consequences. TM patients who are not transfused will only survive for a few years, although there is some variability in the age at which transfusions become necessary.1 More than 70% of patients require transfusions by two years of age, and more than 90% require transfusions by five years of age. However, 5% to 10% of patients, who are usually designated as having "thalassemia intermedia" (TI), are able to maintain reasonable levels of hemoglobin (>70 g/L) without regular transfusions. Such TI patients usually have genetic mutations that result in less severe hematological disease.