Hemophilia: Factor Deficiencies
Advanced, Organ-Based and Clinical Sciences
Hemophilia occurs with an incidence of about 1/10,000 and follows an X-linked recessive inheritance pattern. Thus, it almost always affects males. There are two major subtypes of this disease: Hemophilia A and Hemophilia B. Hemophilia A is a functional factor VIII deficiency while Hemophilia B is a functional factor IX deficiency.
Signs of hemophilia include hemarthrosis, bleeding into soft tissue/muscle after mild trauma, and hematuria. Earlier in life, it may manifest as excessive bleeding following circumcision or altered mental status due to intracranial hemorrhage. It is impossible to distinguish between these two conditions without a factor activity assay. Routine coagulation studies demonstrate normal bleeding time and protime (PT) with prolonged activated partial thromboplastin time (aPTT).
Treatment options for these conditions include replacing with the relevant factor concentrate or administering a blood product containing the defective factor. Patients with mild to moderate Hemophilia A may respond to DDAVP.