Hemophilia – Factor VIII or IX Deficiency

Hemophilia A and hemophilia B are bleeding disorders caused by genetic variants in the F8 or F9 gene that result in deficiencies of factor VIII (FVIII) in hemophilia A or factor IX (FIX) in hemophilia B, respectively.  These disorders are clinically indistinguishable and present with bleeding symptoms that range from mild to severe, depending on the underlying defect (ie, the frequency and severity of bleeding is based on the level of factor activity ). Hemophilia occurs in an estimated one in 10,000 births worldwide, and 80-85% of cases are hemophilia A.  Both hemophilia A and B are rare in females. Acquired hemophilia, an autoimmune disorder, is rarer, occurring in one to two individuals per million.  Carriers of hemophilia and those with subhemophilia (in which FVIII activity is reduced, but not to the extent seen in mild hemophilia) are also at risk for bleeding complications during surgical procedures  and can pass hemophilia to offspring. A workup for hemophilia typically involves tests such as prothrombin time (PT), partial thromboplastin time (PTT), mixing studies, and factor assays to identify the factor deficiency.

Tabs Content
Content Review: 
September 2018

Last Update: December 2019