1. Children's Hospital of Michigan, Detroit, Michigan.
2. Columbia University, New York, New York.
3. Children's Hospital Los Angeles, Los Angeles, California.
4. Mattel Children's Hospital at University of California Los Angeles, Los Angeles, California.
5. Children's National Medical Center, Washington, D.C.
6. Seattle Children's Hospital, Seattle, Washington.
7. Arkansas Children's Hospital, Little Rock, Arkansas.
8. Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania.
9. University of Utah, Salt Lake City, Utah.
10. University of Virginia Children's Hospital, Charlottesville, Virginia.
11. National Institute of Child Health and Human Development, Bethesda, Maryland.