1. Department of Clinical Epidemiology, Leiden University Medical Center, Leiden;
2. Academic Medical Center, Emma Children's Hospital, Amsterdam;
3. University Medical Center Utrecht, Hematology and Van Creveldkliniek, Utrecht;
4. Erasmus Medical Center, Sophia Children's Hospital, Rotterdam;
5. Rehabilitation Center “De Trappenberg,” Huizen;
6. Netherlands Hemophilia Society, Badhoevedorp;
7. Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden; and
8. Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, the Netherlands