1. Department of Genetics and Institute for Diabetes, Obesity, and Metabolism (S.R., J.Z., Z.L., K.H.K.), 12-126 Translational Research Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-5156;
2. Department of Transplantation (C.L., A.N.), University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104;
3. Division of Endocrinology and Metabolism (K.K.T., N.M.F.-T., A.F.S.), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261;
4. Department of Pediatric Diabetes and Endocrinology (J.A.K.), Baylor College of Medicine, Houston, Texas 77030