Alpha-thalassemia

Alpha-thalassemia is an inherited blood disorder and a form of thalassemia, a group of inherited conditions that impair the production of hemoglobin, the molecule that carries oxygen in the blood. Symptoms depend on how deficient hemoglobin is and include anemia, pallor, tiredness, an enlarged spleen, iron overload, abnormal bone structure, jaundice and gallstones; in severe cases death follows, often in infancy or before birth. The disease is characterised by reduced production of the alpha-globin component of hemoglobin, caused by inherited mutations affecting the genes HBA1 and HBA2. Management centres on blood transfusion every three to four weeks, with folate supplementation, iron chelation and removal of the spleen as further measures, and bone marrow transplant from a well matched donor can also treat it. Thalassemias were first identified in severely sick children in 1925, with the alpha and beta subtypes distinguished in 1965. A mild form protects against malaria, which may be an advantage where malaria is endemic.