1. Medical College of Wisconsin/Children's Research Institute of the Children's Hospital of Wisconsin; Milwaukee Wisconsin
2. Johns Hopkins University School of Medicine; Baltimore Maryland
3. Washington University School of Medicine; St. Louis Missouri
4. University of Missouri-Kansas City/Children's Mercy Hospital; Kansas City Missouri
5. Northwestern University-Children's Memorial Hospital; Chicago Illinois
6. Guy's and St. Thomas’ Foundation Trust; London United Kingdom
7. East Carolina University Brody School of Medicine; Greenville North Carolina
8. Children's National Medical Center/The George Washington University School of Medicine and Health Sciences; Washington District Columbia
9. Division of Hematology/Oncology, Department of Pediatrics; Vanderbilt-Meharry Center of Excellence in Sickle Cell Disease, Children's Hospital at Vanderbilt; Nashville Tennessee