Table I.

Summary of the phenotypic features of the accelerated clearance mutants of type 1 von Willebrand disease (type 1C VWD). A predominant accelerated clearance phenotype can be documented in approximately 15% of type 1 VWD cases.

Accelerated Clearance Type 1 von Willebrand Disease: (Type 1C)
• VWF:Ag <30% often <15%
• VWF:pp to VWF:Ag ratio >2 up to >10
• Exaggerated DDAVP response >4-fold up to 10-fold
• Short term benefit from DDAVP (2–4 h)
• Plasma VWF half-lives <3 h
• Subtly abnormal VWF multimer profiles

VWF:Ag, von Willebrand antigen; VWFpp, von WiIlebrand factor propeptide; DDAVP, desmopressin.