1. ; Department of Clinical Chemistry and Division Emma Children's Hospital; Academic Medical Center, University of Amsterdam; Amsterdam The Netherlands
2. ; University Children's Hospital; Marburg Germany
3. ; Laboratory of Pediatrics and Neurology; University Hospital Nijmegen; The Netherlands
4. ; Department of Pediatrics; University of Leuven; Belgium
5. ; Pediatric Clinic; University of Catania; Italy
6. Children's Clinic; Siegen Germany