Biological diagnosis of von willebrand disease and its difficulties

ABSTRACT

Von Willebrand disease is the most common inherited bleeding disorder, with autosomal genetic transmission, dominant in most cases. It is due to quantitative and / or qualitative deficiency of Von Willebrand factor, a multimeric complex glycoprotein that plays 2 central roles in hemostasis, since it is implicated in adhesion and aggregation of platelets under conditions of high shear forces and acts as a carrier for coagulation factor VIII in plasma. Clinically, this disease is mostly characterized by mucocutaneous bleeding and marked clinical heterogeneity, even in the same family, going from severe to uncouth forms or even asymptomatic. Laboratory diagnosis is based on 3 levels of hemostasis testing. Screening tests making suspicion of the disease, must be completed by specific assays to estabilish the diagnosis. Discriminating tests allow accurate characterization of the numerous types and subtypes of the disease, a crucial step to adapt therapeutics. The classification based on the accumulating knowledge of the different phenotypes, differentiate between quantitative [types 1 and 3] and qualitative deficiencies [types 2]. Von Willebrand disease's diagnosis is not, often easy. In fact, several technical or genetic factors and different physiopathological circumstances interfere in the interpretation of explorations results and cause diagnostic difficulties that will be discussed