Hemoglobin is composed of heme and globin. The function of hemoglobin is to transport oxygen from the lungs to the tissues. Three main types of normal hemoglobin are found in adults: hemoglobin A, hemoglobin A2 and hemoglobin F, namely alpha, beta, gamma or delta, which determine the type of hemoglobin. All normal hemoglobin is a combination of alpha chain and non-alpha chain. The alpha globin gene is located on chromosome 16. Hemoglobin A consists of a pair of alpha globin chains and a pair of beta globin chains, which produce 95% to 98% of adult hemoglobin.
