The current observational trial, Follow-Up Study ((FUS) II includes enhanced neuropsychological, brain, cardiac, and pulmonary evaluations for this very well characterized cohort of subjects. Measures of spleen and renal function and markers of DNA damage will continue to be collected. Assessment of other target organs in sickle cell disease including pulmonary and cardiac function will be performed in addition to evaluation of developmental aspects of sickle cell disease (SCD) and potential HU toxicity.
