The current classification includes types 1 and 3, which are characterized by quantitative deficiencies of von Willebrand
factor (VWF), as well as types 2A, 2B, 2M, and 2N, which are qualitative variants.
Three main types are:
- Type 1 – partial quantitative deficiency of vWF.
- Type 2 – qualitative abnormalities of VWF; 4 subtypes:
- 2A – characterized by reduced or absent high-molecular-weight vWF.
- 2B – gain of function in VWF that increases its affinity for platelets.
- 2M – caused by reduced VWF interactions with platelets or collagen.
- 2N – results from reduced binding of VWF to FVIII.
- Type 3 – virtual absence of the VWF protein with associated very low FVIII levels.