The purpose of this study is to demonstrate that a sufficient number of iron-overloaded thalassemia (THAL), Sickle Cell Disease (SCD)and Diamond Blackfan Anemia (DBA) populations with similar duration of chronic transfusion, and age at start of transfusions would be available for a confirmatory study. The study will examine the hypothesis that a chronic inflammatory state in SCD leads to hepcidin- and cytokine-mediated iron withholding within the RES (reticuloendothelial system), lower plasma NTBI (non-transferrin bound iron) levels, less distribution of iron to the heart in SCD.