Thalassemia
Introduction Thalassemia syndromes encompasses a spectrum of haemoglobin disorders that arise from impaired production of globin chains. A normal haemoglobin consists of two α chain (encoded by two closely linked genes on chromosome 16) and two β chain (encoded by a single gene on chromosome 11). Pathophysiology The imbalance of globin production is variable, and the degree of accumulation of the unpaired globin chains is directly related to the severity of the disease phenotype. In general, α-thalassemia occurs as a result of gene deletion. α-thalassemia trait 2 (loss of one α globin gene [αα/α−]); α-thalassemia trait 1, also referred to as α-thalassemia minor (loss of two α globin genes [αα/− − or α−/α−]); Hemoglobin H (HbH) disease (loss of three alleles [α−/− −]); and Hemoglobin Barts hydrops fetalis (loss of all four α globin loci [− −/− −]). β-thalassemia occurs as a result of mutations Subdivided into major, intermedia, and minor types. The hallmark of thalassemia is anaemia t...