<prompt> Which of the following true regarding Hemophilia ASerum levels of factor VIII are decreasedDeficiency of factor IXPT increasedFIT decreased  <response>: 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 