1. Departments of Pediatrics (M.J.E.W., W.O., W.H.S.-B., J.M.W.), Leiden University Medical Center, 2300 RC Leiden, The Netherlands
2. Endocrinology and Metabolic Diseases (A.M.P.), Leiden University Medical Center, 2300 RC Leiden, The Netherlands
3. Hospital for Children and Adolescents (R.W.P.), University of Leipzig, 04317 Leipzig, Germany
4. Department of Pediatric Endocrinology (O.B.), Charité-Universitätsmedizin Berlin, D-13353 Berlin, Germany