VWF is synthesized in endothelial cells and megakaryocytes. Type I - by far the most common form. Inheritance is autosomal dominant. Most patients are heterozygotes. Mild to moderate decrease in plasma VWF concentrations.
Most patients have mild disease with excessive bleeding after surgery or trauma.
Type II - Rare, patients have normal levels but dysfunctional VWF, leading to decreased VWF activity. IIb - also a deficiency in high molecular weight VWF, but due to inappropriate binding of VWF to platelets. This leads to platelet aggregation and eventual clearing of the aggregates from the circulation. Type III - Inheritance is autosomal recessive. I patients and therefore homozygous.