From the Human Genetics Center (M.F., E.B.) and the Institute of Molecular Medicine (E.B.), University of Texas at Houston Health Science Center; the Department of Epidemiology, University of Texas M.D. Anderson Cancer Center, Houston (C.I.A.); the Department of Human Genetics, University of Michigan, Ann Arbor (S.K., C.F.S.); and the Division of Hypertension, Department of Internal Medicine, Mayo Clinic, Rochester, Minn (S.T.T.). (At 1998-05-12)