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': 'Which is not true regarding Bernard Soulier syndrome - \nSelect and explain. \nA. Ristocetin aggregation is normal, B. Aggregation with collagen and ADP is normal, C. Large platelets, D. Thrombocytopenia', 'role': 'user'}, {'content': "Answer: A \nExplanation: Bernard Soulier Syndrome\n\nAutosomal recessive disorder.\nDeficiency/dysfunction of Gp Ib/ IX receptor\nPlatelets cannot adhere to subendothelium because of lack of above receptors for VWF which mediates platelets adhesion.\nPlatelet, aggregation is normal in response to standard agonists ( collagen, ADP, thrombin) but platelets fail to\xa0aggregate in response to ristocetin as it acts by a different mechanism.\n\nOther laboratory parameters :\n\nThrombocytopenia may be present.\nPlatelets on smear are abnormally large.\nBleeding time is abnormally prolonged.\nVWF factor levels in plasma are normal.\n\tClinical presentation :\nRecurrent episodes of severe mucosal hemorrhage.\nGlanzman's thrombasthenia\nAutosomal recessive disorder.\nDeficiency/dysfunction of Gp IIb/ IIIa complex.\nPlatelets cannot aggregate because of lack of above receptors for fibrinogen which form bridges between platelets during aggregation.\nPlatelet aggregation is largely abnormal.Platelests fail to aggregate in response to standard agonists ( collagen, ADP, thrombin) as these require fibrinogen binding but aggregate normally to ristocetin as it causes platelet clumping by a different mechanism.\n\n\tOther laboratory parameters :\nPlatelet number is usually normal\nPlatelet morphology is usually normal..\nBleeding time is abnormally prolonged.\nVWF factor levels in plasma are normal.\xa0\n\tClinical presentation\nRecurrent episodes of severe mucosal hemorrhage.", 'role': 'assistant'}]