We conclude that vWF mutation may be an under recognized cause of hemophilia, especially in cases where the inheritance pattern is not consistent with X-linked transmission.
Results from 22 International Haemophilia Training Centres (IHTCs) provide target values for the prothrombin time (PT), activated partial thromboplastin time (APTT), factor VIII:C, IX:C and von Willebrand factor assays, against which the performance of haemophilia centres (HCs) in developing countries can be assessed.
Patients presenting with a low FVIII:C and with normal VWF levels are usually presumed to have hemophilia (males) or be carriers for hemophilia (females).
Non-mixing led to substantial reduction in VWF and factors in about 25% of samples, that in some cases could lead to misdiagnosis of VWD or haemophilia.
Several studies of ITI therapy are ongoing with the aim of clarifying unresolved issues in haemophilia management including the role of von Willebrand factor in inhibitor eradication.