1. Department of Clinical Chemistry and Transfusion Medicine, University of Gothenburg, Gothenburg, Sweden;
2. Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden;
3. Center of Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway;
4. Laboratory of Immunohematology, Department of Hematology, Aarhus University Hospital, Aarhus, Denmark;
5. Department of Pediatrics, Sahlgrenska University Hospital, Gothenburg, Sweden;
6. Department of Medical Biosciences, Umeå University, Umeå, Sweden;
7. Department of Pediatrics, University Central Hospital of Helsinki, Helsinki, Finland;
8. Department of Pediatrics, University Hospital, Reykjavik, Iceland;
9. Department of Pediatrics, Oslo University Hospital, Oslo, Norway;
10. Department of Women's and Children's Health, University Children's Hospital, Uppsala, Sweden;
11. Department of Pediatrics, Aarhus University Hospital Skejby, Aarhus, Denmark; and
12. Department of Clinical Genetics, Lund University, Lund, Sweden