1. Paediatric Department, Oslo University Hospital, Oslo, Norway
2. Intervention Centre and Department of Surgery, Oslo University Hospital, Oslo, Norway
3. Faculty of Medicine, University of Oslo, Oslo, Norway
4. Department of Surgery, Oslo University Hospital, Oslo, Norway
5. Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
6. Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
7. Institute of Biomedical & Clinical Science, University of Exeter Medical School, Exeter, U.K.
8. Department of Virology, School of Medicine, University of Tampere, Tampere, Finland
9. Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland
10. Division of Paediatrics, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
11. Department of Endocrinology, Oslo University Hospital, Oslo, Norway