: The defect function of the
von Willebrand factor (VWF) in carrying
factor VIII (FVIII) leads to
von Willebrand disease type 2N (VWD 2N) which could be easily misdiagnosed as
hemophilia A. Differentiating of VWD 2N from
hemophilia A is crucial for patient treatment and genetic counseling. As a retrospective study, we aimed to evaluate the current diagnostic work-up of Iranian patients with mild/moderate deficiency of FVIII levels and the possibility of misdiagnosis of VWD 2N as
hemophilia A. All patients who referred to the reference coagulation laboratory at the Iranian
Blood Transfusion Organization in a 10-months period for
bleeding diathesis work-up with the request of FVIII activity level were included. Clinical and laboratory phenotypes including International Society on
Thrombosis and Hemostasis -
Bleeding Assessment Tool, FVIII activity, VWF
antigen, VWF
ristocetin cofactor, and FVIII binding capacity of VWF were assessed on suspected cases for VWD 2N. In total, the results of 896 patients for investigation of VWD 2N were evaluated and five new patients were identified within unrelated families with abnormal VWF:FVIIIB levels. Four were heterozygous for VWD 2N and one homozygous whom all were misdiagnosed as
hemophilia A and underwent inappropriate treatments. The median
bleeding score of the VWD 2N population was nine (4-13). In Iran, probably a significant number of VWD 2N patients are misdiagnosed as
hemophilia A due to insufficient test panel for subtyping of
von Willebrand disease. This study also emphasized the need for inclusion of the VWF:FVIIIB in suspected
hemophilia A to achieve an optimal treatment strategy.