1. Sickle Cell Branch, National Heart, Lung, and Blood Institute (NHLBI),
2. Molecular and Clinical Hematology Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and NHLBI,
3. Office of the Clinical Director, NIDDK, and
4. Division of Cardiovascular Sciences, Office of Biostatistics Research, NHLBI, National Institutes of Health, Bethesda, MD; and
5. Sidney Kimmel Comprehensive Cancer Research Center, Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD