1. ; Division of Medical Genetics, Department of Pediatrics; Duke University Medical Center; Durham North Carolina
2. ; Barbara Bush Children's Hospital; Portland Maine
3. North Carolina State Laboratory of Public Health; Raleigh North Carolina
4. ; Division of Genetics and Metabolism, Department of Pediatrics; University of North Carolina; Chapel Hill North Carolina
5. Division of Public Health, Department of Health and Human Services; Women's and Children's Health; Raleigh North Carolina, USA