1. Division of Pediatric Endocrinology (P.F.-P.), Diabetes and Obesity Unit, Department of Pediatrics and Adolescent Medicine, Ulm University, 89081 Ulm, Germany
2. Touchstone Diabetes Center (P.F.-P., Q.A.W., I.W.A., J.M.R., P.E.S.), Department of Internal Medicine
3. Department of Cell Biology (P.E.S.), The University of Texas Southwestern Medical Center, Dallas, Texas 75390-8549;