Willebrand's disease (VWD) is a genetic and hereditary disease which causes a qualitative or quantitative alteration of VWF causing more or less severe bleeding. VWDs are categorized into 3 types according to their faults :
Type 1 : the level of VWF is in lower quantity or having a shorter lifespan in the bloodstream, inducing a partial quantitative defect.
Type 2 : the level of VWF is in normal quantity or slightly reduced but it is altered in its structure inducing a qualitative deficit.
Type 3 : this is the most serious type because the VWF level is greatly reduced <1% of the normal associated with a decreased level of FVIII.