1. Division of Hematology and Oncology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN;
2. McKusick-Nathans Institute of Genetic Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD;
3. Division of Blood Disorders, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, GA;
4. Department of Medicine,
5. Department of Pediatrics, and
6. Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA;
7. Department of Biostatistics, Boston University School of Public Health, Boston, MA;
8. Division of Pediatric Hematology, Department of Pediatrics, School of Medicine, Johns Hopkins University, Baltimore, MD; and
9. Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN