1. Department of Pediatric Hematology Emma Children's Hospital, Amsterdam UMC, University of Amsterdam Amsterdam the Netherlands
2. Center for Benign Hematology, Thrombosis and Hemostasis—Van Creveldkliniek Wilhelmina Children's Hospital, University Medical Center Utrecht Utrecht the Netherlands
3. Department of Epidemiology and Data Science Amsterdam UMC, University of Amsterdam Amsterdam the Netherlands
4. Department of Pediatric Hematology Amalia Children's Hospital, Radboud University Nijmegen Medical Center Nijmegen the Netherlands
5. Department of Pediatric Hematology Beatrix Children's Hospital, University Medical Center Groningen Groningen the Netherlands
6. Department of Pediatric Hematology and Stem Cell Transplantation Unit Willem‐Alexander Children's Hospital, Leiden University Medical Center Leiden the Netherlands
7. Department of Pediatric Hematology Mosakids Children's Hospital, Maastricht UMC+ Maastricht the Netherlands
8. Department of Pediatrics Juliana Children's Hospital, Hagaziekenhuis Den Haag the Netherlands
9. Department of Pediatric Hematology and Oncology Erasmus MC Sophia Children's Hospital, University Medical Center Rotterdam Rotterdam the Netherlands