Which statement best describes Type 3 von Willebrand disease?

Which statement best describes Type 3 von Willebrand disease?

• A. Type 1 deficiency
• B. Type 2 defective
• C. Type 3 complete absence of vWF
• D. Type 4 abnormal expression

Answer: (C)

Understanding von Willebrand disease types hinges on how much von Willebrand factor (VWF) is present and how well it works. Type 3 represents the most severe scenario: there is essentially no VWF in the circulation. That means both the amount and activity of VWF are profoundly reduced, so platelets can’t bind properly to subendothelial collagen, and the stabilization of factor VIII in plasma is lost, leading to significantly prolonged bleeding and more severe mucosal bleeding. Because VWF is nearly absent in this type, tests show very low VWF antigen and VWF activity, and factor VIII levels are also markedly reduced. Desmopressin, which releases stored VWF from endothelial cells, is usually ineffective when there’s little to no VWF to release, so treatment relies on replacing VWF with concentrates that contain the protein. The other types reflect partial deficiency (Type 1) or qualitative defects (Type 2) where some VWF is present or it’s present but dysfunctional, not a complete absence. Type 4 isn’t a standard modern category.

Understanding von Willebrand disease types hinges on how much von Willebrand factor (VWF) is present and how well it works. Type 3 represents the most severe scenario: there is essentially no VWF in the circulation. That means both the amount and activity of VWF are profoundly reduced, so platelets can’t bind properly to subendothelial collagen, and the stabilization of factor VIII in plasma is lost, leading to significantly prolonged bleeding and more severe mucosal bleeding.

Because VWF is nearly absent in this type, tests show very low VWF antigen and VWF activity, and factor VIII levels are also markedly reduced. Desmopressin, which releases stored VWF from endothelial cells, is usually ineffective when there’s little to no VWF to release, so treatment relies on replacing VWF with concentrates that contain the protein.

The other types reflect partial deficiency (Type 1) or qualitative defects (Type 2) where some VWF is present or it’s present but dysfunctional, not a complete absence. Type 4 isn’t a standard modern category.