1. Division of Medical Genetics; A. I. duPont Hospital for Children; Wilmington; Delaware
2. Division of Genetics and Metabolism; Children's National Medical Center; Washington; District of Columbia
3. Division of Clinical Genetics; Levine Children's Hospital; Charlotte; North Carolina
4. Section of Clinical Genetics; St. Christopher's Hospital for Children; Philadelphia; Pennsylvania
5. Center for Integrative Brain Research; Seattle Children's Research Institute; Seattle; Washington
6. Division of Genetics; The Children's Hospital of Philadelphia; Philadelphia; Pennsylvania
7. Department of Biomedical Research; Nemours' Children's Clinic; Wilmington; Delaware