The authors are grateful to their Clinical Advisory Board for valuable contributions: Anne Bassett, Prudence Fisher, Ellen Leibenluft, Deborah Levy, Michel Maziade, Kathleen Merikangas, Joe Piven, and Peter Szatmari. John Burian and William Valentine-Cooper contributed extensive and essential programming support. The authors also thank the investigators who contributed these data sets to the Human Genetics Initiative (HGI) and the families who participated in these studies, as well as HGI staff at Washington University for their assistance throughout the data review process.