DISCOVERY OF TYPE 3 VON WILLEBRAND DISEASE IN A COHORT OF PATIENTS WITH SUSPECTED HEMOPHILIA A IN CÔTE D’IVOIRE

Aim : Type 3 von Willebrand disease (VWD) is the most severe form of VWD, characterized by a near-total absence of von Willebrand factor (vWF) leading to a huge deficiency in plasmatic factor VIII (FVIII). VWD may be confused with hemophilia A, sometimes leading to misdiagnosis. The purpose of this work was to finalize the biological diagnosis of patients with FVIII activity deficiency in Abidjan, in order to guide the best type of management. Methods: We conducted a cross-sectional descriptive study from June 2018 to April 2019. Forty-nine patients, all of whom had lower FVIII levels or had been referred for bleeding disorder, were monitored in the clinical hematology service. Pro-coagulant activity of coagulation factors was performed in Abidjan. The assays for von Willebrand antigen and activity were performed at Nîmes University Hospital in France. Results: The mean age of patients was 13.8 years (1 – 65) and 86% were Ivorian. FVIII deficiency was discovered during a biological checkup, circumcision or post-traumatic bleeding, in 33%, 31% and 29% respectively. The FVIII level of patients was classified as severe (89.8%), moderate (8.2%) and mild (2%). Only one patient had a quantitative deficiency of von Willebrand factor (vWF: Ag <3%) with undetectable von Willebrand factor activity (vWF: Ac) and an FVIII level <1%. Conclusion: Not all of the constitutive deficits of FVIII are hemophilia A. It was very important to assess the Willebrand factor of these patients followed in Côte d'Ivoire for whom hemophilia A had been suspected.