talassemier

Talassemier, also known as thalassemias, are a group of inherited blood disorders characterized by reduced or absent production of alpha or beta globin chains, leading to imbalanced hemoglobin synthesis. They are usually inherited in an autosomal recessive pattern; individuals who inherit one mutant gene are carriers and may have mild symptoms.

Alpha-thalassemia results from deletions of HBA1 and HBA2 genes on chromosome 16, with a spectrum from silent carrier to Hb H disease to hydrops fetalis. Beta-thalassemia arises from mutations in the HBB gene on chromosome 11, with beta-thalassemia major (Cooley’s anemia), intermedia, and minor phenotypes.

The globin imbalance causes ineffective erythropoiesis and hemolysis, yielding a chronic, often microcytic and hypochromic anemia. In beta-thalassemia, HbA2 levels are typically elevated; in newborns, Hb Bart’s (gamma4) may be seen in severe alpha-thalassemia.

Signs include pallor, fatigue, hepatosplenomegaly, and bone changes due to expanded marrow. Severe forms cause growth retardation and transfusion dependence.

Diagnosis involves complete blood count showing microcytic anemia, hemoglobin electrophoresis or HPLC to identify HbA2 and HbF, and genetic testing for definitive confirmation.

Management includes regular red cell transfusions for severe disease, iron chelation therapy to prevent iron overload, folic acid supplementation, and splenectomy in selected cases. Curative options include hematopoietic stem cell transplantation in appropriately matched patients. Prenatal and carrier screening and genetic counseling reduce risk.

Epidemiology: talassemier are most common in the Mediterranean, Middle East, South Asia, and parts of Africa, with variable prevalence worldwide.