1. Endocrine Unit, Department of Medicine (J.S.F., J.J.W., B.Z.L., S.M.B., H.J., R.M.N.), Massachusetts General Hospital, Boston, Massachusetts 02114
2. Biostatistics Center (H.L.), Massachusetts General Hospital, Boston, Massachusetts 02114
3. Pediatric Nephrology Unit, Department of Pediatrics (H.J.), Massachusetts General Hospital, Boston, Massachusetts 02114