A detailed iron burden, transfusion and chelation history will be obtained from chart review or from participant recall.
Iron burden data will include: 1) documentation of liver iron, and 2) average annual ferritin values.
Transfusion data will include: (1) age at onset of regular transfusions, (2) years of chronic transfusion therapy, and (3) pre-transfusion Hb calculated as average of all assessments for each year.
