This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Von willebrands disease all are true except -a) Factor VIII C deficiencyb) BT Prolongedc) Normal Ristocetin testd) Defective aggregation \nSelect and explain. \nA. a, B. bc, C. ac, D. b', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Von willebrand disease \n\nVon willebrand disease is characterized by the deficiency of vWF, while the synthesis of factor VIIIc is normal.\nvWF has two major function : -\n\n\nHelps in platelet adhesion\nStabilizes factor VIIIc.\n\n\nSo, deficiency of vWF results in manifestation of both.\n\n1. Platelet adhesion defect\n\nBleeding from small venules and capillaries of skin and mucous membrane e.g., epistaxis.\nMenorrhagia and GI bleeding.\nProloged bleeding time\n\n2. Coagulation defect (due to factor VIII dysfunction)\n\nBleeding into weight bearing joints.\nLarge post traumatic ecchymoses or hematoma.\nProlonged bleeding after any form of surgical procedure or a laceration.\nProlonged PTT.\n\n\nvWF 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.', 'role': 'assistant'}]