Thalassemia, a genetic disorder, results in the production of abnormal hemoglobin (Hb). A mature Hb molecule is an oligomer composed of four subunits (monomers) two alpha-globin (α-globin) and two beta-globin (β-globin) polypeptides attached to a heme prosthetic group. In alpha-thalassemia (α-thalassemia), there is a decrease in the making of α-globin chains, and this results in a reduced red cell (erythrocyte) Hb level. In beta-thalassemia (β-thalassemia), there is a decline in the production of β-globin chains leading to unpaired α-globin chains as a by-product, which, being unstable erythroid precursors, precipitate and result in injury to the membrane as well as the unfolding of the protein response leading to toxicity and death of the cells. In Thalassemia major, the child inherits two defective globin genes (one each from a parent), while in Thalassemia minor, only one defective globin gene is inherited (from only one parent). Ineffective erythropoiesis is responsible for the typical symptoms of thalassemia. Classical symptoms of Thalassemia major include pallor, poor development, and abdominal enlargement in children and infants. Radiological evidence in these children and young adults includes thinning of the long bones with a “sun-ray appearance” and “dilation of the marrow cavities”. The skull also develops a “hair-on-end” appearance due to an increase in the width in the diploic space. Some patients also have enlarged maxillary sinuses along with a tendency to have a maxillary overbite.
Guidelines for the Management of Transfusion Dependent Thalassaemia. 3rd ed. TIF. 2014. Retrieved June 14, 2021. Available from: https://thalassaemia.org.cy/publications/tif-publications/guidelines-for-the-management-of-transfusion-dependent-thalassaemia-3rd-edition-2014/.