1. Research Institute Children's Cancer Center, Hamburg, Germany;
2. Department of Pediatric Hematology and Oncology, University Medical Center Hamburg Eppendorf, Hamburg, Germany;
3. University Children's Hospital Münster, Pediatric Hematology and Oncology, Albert-Schweitzer-Campus 1, Münster, Germany;
4. Centre of Chronic Immunodeficiency, University of Freiburg, Freiburg, Germany;
5. Department of Voice, Speech and Hearing Disorders, University Medical Center Hamburg Eppendorf, Hamburg, Germany;
6. Section of Pediatric Stem Cell Transplantation, Department of Pediatric Hematology-Oncology, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia;
7. Department of Pediatric Hematology and Oncology, Medical School Hannover, Hannover, Germany;
8. Department of Clinical Genetics, Odense University Hospital, Odense, Denmark;
9. Pediatric Hematology, Oncology and Immunology, Klinikum Stuttgart/Olga Hospital, Stuttgart, Germany;
10. Gilead Children's Hospital, Bielefeld, Germany;
11. Pediatric Hematology, Oncology, University of Essen, Essen, Germany;
12. Prof Hess Children's Hospital, Bremen, Germany;
13. Department of Pediatrics, University of Ulm, Ulm, Germany;
14. Department of Pediatric Hematology and Oncology, Teaching Hospital Motol and 2nd Medical School, Charles University, Prague, Czech Republic;
15. Department of Pediatrics, Technical University Munich, Munich, Germany; and
16. University Medical Center Hamburg Eppendorf, Center for Diagnostic, Hamburg, Germany