<prompt> Von willebrands disease all are true except -a Factor VIII C deficiencyb BT Prolongedc Normal Ristocetin testd Defective aggregationabcacb  <response>: Von willebrand disease Von willebrand disease is characterized by the deficiency of vWF, while the synthesis of factor VIIIc is normal.vWF has two major function : -Helps in platelet adhesionStabilizes factor VIIIc.So, 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.Menorrhagia and GI bleeding.Prologed bleeding time2. Coagulation defect due to factor VIII dysfunctionBleeding into weight bearing joints.Large post traumatic ecchymoses or hematoma.Prolonged bleeding after any form of surgical procedure or a laceration.Prolonged PTT.vWF can be assayed by restocetin agglutination test which measures the ability of restocetin to promote the interaction between vWF and platelet membrane glycoprotein Ib-IX. 