This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
[{'content': 'Which of the following true regarding Hemophilia A \nSelect and explain. \nA. Serum levels of factor VIII are decreased, B. Deficiency of factor IX, C. PT increased, D. FIT decreased', 'role': 'user'}, {'content': 'Answer: A \nExplanation: * Hemophilia is an X linked disorder of coagulation caused by the deficiency in a circulating plasma protein. Hemophilia A is caused by the deficiency of factor VIII, and hemophilia B is caused by the deficiency of factor IX. * It is PTT which is affected (increased) and not PT (unaffected). * Factor VIII is involved in the intrinsic pathway which is measured by PTT and not in extrinsic pathway which is measured as PT. * Bleeding is the common manifestation of hemophilia and the common bleeding manifestations are hemahoses, hematomas, mucocutaneous bleeding, intracranial bleeding, hematuria and pseudotumor. REF : HARRISONS 21ST ED', 'role': 'assistant'}]