1. Division of Cancer Genetics and Epidemiology, Lombardi Comprehensive Cancer Center, Division of Endocrinology and Metabolism, Georgetown University School of Medicine, Washington, D.C.
2. Department of Biomathematics and Biostatistics, Georgetown University School of Medicine, Washington, D.C.
3. Department of Pediatrics, University of Kansas Medical Center, Kansas City, Kansas.
4. Division of Endocrinology and Metabolism, Georgetown University School of Medicine, Washington, D.C.
5. Bioanalytical Core Laboratory, Georgetown Clinical Research Center, Georgetown University Medical Center, Washington, D.C.
6. Department of Laboratory Medicine, Children's National Medical Center and Departments of Pediatrics and Pathology, The George Washington University School of Medicine, Washington, D.C.