1. From the Department of Nephrology (H.C., J.A.J., H.A.R.B., H.A.K., B.B.), University Medical Center, Utrecht, The Netherlands; Department of Internal Medicine (C.A.J.M.G.) and Department of Clinical Chemistry (B.B.v.d.M., H.M.D., R.J.K.), Meander Medical Center, Amersfoort, The Netherlands; and Genomics Laboratory (D.v.L., F.C.P.H.), University Medical Center, Utrecht, The Netherlands.