1. From the National Heart, Lung, and Blood Institute (J.J.C.), and the National Human Genome Research Institute (T.A.M.), National Institutes of Health, Bethesda, Md; University of Washington, Seattle (A.M.A., B.M.P.); University of California at Davis (C.H.H.); New England Medical Center, Tufts University, Boston, Mass (J.F.P.); University of Pittsburgh, Pittsburgh, Pa (L.H.K.); and University of Vermont, Burlington (M.C.).