1. Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
2. University of Utah, Salt Lake City, Utah, USA
3. Children’s National Medical Center, Washington, DC, USA
4. Children’s Hospital of Michigan, Detroit, Michigan, USA
5. Le Bonheur Children’s Hospital, Memphis, Tennessee, USA
6. Seattle Children’s Hospital, Seattle, Washington, USA
7. Children’s Hospital Los Angeles, Los Angeles, California, USA
8. Mattel Children’s Hospital at University of California, Los Angeles, California, USA
9. Children’s Hospital of Richmond, Richmond, Virginia, USA
10. Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA
11. Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
12. C. S. Mott Children’s Hospital, Ann Arbor, Michigan, USA
13. Phoenix Children’s Hospital, Phoenix, Arizona, USA
14. St Louis Children’s Hospital, St Louis, Missouri, USA