1. From the Seattle Children's Research Institute (M.W.M., X.R.D., V.J.H.) and Departments of Pediatrics and Pathology (M.W.M.), University of Washington, Seattle; Curriculum in Genetics and Molecular Biology (M.W.M., V.J.H.), Department of Genetics, University of North Carolina, Chapel Hill; and Department of Medicine (J.N.R.), Division of Endocrinology & Metabolism, Washington University, St Louis, MO.