Von Willebrand Disease Type 1 vs Type 2: Age-Related Changes

Understanding VWD Types and Their Characteristics

• Type 1 VWD is characterized by a partial quantitative deficiency of VWF, with VWF levels typically <30 IU/dL but with functionally normal VWF (VWF:RCo/VWF:Ag ratio >0.5-0.7) 1, 3
• Type 2 VWD involves qualitative defects in VWF structure or function, with subtypes including Type 2A, Type 2B, Type 2M, and Type 2N, each with distinct characteristics 1, 3

Age-Related Changes in VWD

• The defective VWF in Type 2 remains dysfunctional regardless of its concentration, explaining why symptoms typically do not improve with age 3

Diagnostic Considerations

• Laboratory testing should include VWF:RCo, VWF:Ag, and FVIII levels to distinguish between VWD types 3, 4
• Repeat testing may be necessary due to variability in VWF levels influenced by external factors 4
• The diagnostic cutoff for VWD is typically <30 IU/dL for VWF:RCo, though patients with levels between 30-50 IU/dL may still have clinically significant disease 4

Common Pitfalls and Caveats

• In Type 2 VWD, increased VWF quantity with age may create false reassurance if only quantitative (not functional) assays are performed 3
• The VWF:RCo/VWF:Ag ratio should always be assessed to distinguish between Type 1 and Type 2 VWD, especially in older patients 3, 4