1. From the Division of Nephrology and Hypertension (S.T.T., G.L.S.), Department of Medicine, and Divisions of Biostatistics (K.R.B., B.L.F.) and Biomedical Informatics (H.S.C., H.S., J.-P.K.), Department of Health Sciences Research, Mayo Clinic, College of Medicine, Rochester, Minn; the Renal Division (A.B.C.), Department of Medicine, Emory University, Atlanta, Ga; and the Human Genetics Center (A.S.R., E.B.), School of Public Health, University of Texas-Houston Health Science Center.