Von Willebrand's disease is caused by a gene that results in an inadequate production of von Willebrand's factor in the bloodstream. The Von Willebrand factor is necessary for platelets to form a blood clot.

Normal Blood Coagulation
Normal blood coagulation requires the complex interaction of as many as 20 different plasma proteins. Many of these factors are manufactured in the liver and are regulated by the activities of enzymes and other cofactors.