The following hereditary bleeding disorders were studied: severe deficiency of vWF, known as von Willebrand disease (vWD subtype III), the vWD subtypes vWD I, vWD IIa, vWD IIb and vWD 2M, deficiency of the platelet receptors GPIa, GPIb and GPIIb–IIIa, and polymorphisms of GPIa, GPIb and GPIIb–IIIa. Here, VWF is linked to hemorrhagic disease.