<prompt> Von willebrands disease all are true except a Factor VIII C deficiencyb B.T. Prolongedc Normal Ristocetin testd Defective aggregationabcacb  <response>: Von Willebrand disease is characterized by the deficiency of vWF, while the synthesis of factor VIIIc is normal.VWF has two major functions -Helps in platelet adhesionStabilizes factor VIIIcSo, deficiency of vWF results in manifestation of both -1 Platelet adhesion defectBleeding from small venules and capillaries of skin and mucous membrane e.g. epistaxis. a Menorrhagia and GI bleedingProlonged bleeding time2 Coagulation defect due to factor VIII dysfunctionBleeding into weight bearing jointsLarge post traumatic ecchymoses or hematomaProlonged bleeding after any form of surgical procedure or a laceration.Prolonged PTTVWF can be assayed by ristocetin agglutination test which measures the ability of ristocetin to promote the interaction between VWF and platelet membrane glycoprotein Ib-IX. 