THALASSEMIA - A genetic disease that results when there is a defect in the synthesis of one (or more) of the subunits of hemoglobin. The subunits are referred to as alpha or beta globin chains. As a result of a genetic defect red blood cells are small and hypochromic (low hemoglobin in the cell). Anemia is common. Incidence is approximately 4 out of 100,000 individuals. Genetic testing is recommended in pregnant females of Mediterranean descent for the purpose of identifying carriers of this potentially serious genetic disease.