1. Department of Pediatric Endocrinology, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
2. Department of Pediatrics and Neonatology, OLVG Oost, Amsterdam, the Netherlands.
3. Department of Pediatrics, Catharina Hospital, Eindhoven, the Netherlands.
4. Endocrine Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.
5. Endocrine Laboratory, Department of Clinical Chemistry, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
6. Department of Endocrinology and Metabolism, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands.