Factor XII (Hageman factor) deficiency
Factor XII deficiency is an inherited disorder that affects a protein (factor XII) involved in blood clotting.
Causes, incidence, and risk factors
When you bleed, the body launches a series of reactions that help the blood clot. This is called the coagulation cascade. The process involves special proteins called coagulation factors. (Factor XII is a coagulation factor in this series of reactions.)
Each factor has a reaction that triggers the next reaction. The final product of the coagulation cascade is the blood clot.
A lack of factor XII does not cause the affected person to bleed abnormally, but the blood takes longer than normal to clot in a test tube.
Factor XII deficiency is a rare inherited disorder.
There are usually no symptoms.
Signs and tests
Factor XII deficiency is usually found when clotting tests are done for routine screening.
Tests may include:
Treatment is generally unnecessary.
The outcome is expected to be good without treatment.
There are usually no complications.
Calling your health care provider
This condition is usually discovered by the health care provider, when prolonged clotting is noticed in the process of running other laboratory tests.
This is an inherited disorder. There is no known way to prevent it.
Kessler C. Hemorrhagic disorders: Coagulation factor deficiencies. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 180.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997-
A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.