Thalassemias are a diverse group of inherited disorders in which the rate of production of certain hemoglobins is decreased leading to an imbalance of globin chains available for hemoglobin dimer construction. This results in the formation of abnormal amounts of structurally normal (normal amino acid sequence) hemoglobins. For instance, if inadequate numbers of b-chains were synthesized, a-chains would be in relative excess and would precipitate.