1. Department of Paediatrics and Adolescent Medicine; The University Hospital Rigshospitalet; Copenhagen Denmark
2. Children's Hospital; Helsinki University Central Hospital; Helsinki Finland
3. Department of Pediatrics; Institution of Clinical Sciences; Sahlgrenska University Hospital; Gothenburg Sweden
4. Department of Medical Biosciences; Clinical Genetics; Umeå University; Umeå Sweden
5. Department of Pediatrics; University Hospital; Oulu Finland
6. Department of Pediatrics; Astrid Lindgrens Hospital; Stockholm Sweden
7. Department of Pediatrics; University Hospital; Reykjavík Iceland
8. Department of Paediatrics; Turku University Hospital; Turku Finland
9. Center for Oncology and Hematology; Children's Hospital; Affiliate of Vilnius University Hospital Santariskiu Klinikos; Vilnius Lithuania
10. Department of Pediatrics; St. Olavs Hospital; Trondheim University Hospital; Trondheim Norway
11. The Institute of Clinical Medicine; The Faculty of Medicine; University of Copenhagen; Denmark