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. When one or more of these clotting factors are missing, there is usually a higher chance of bleeding.
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.
Symptoms
There are usually no symptoms.
Signs and tests
Factor XII deficiency is usually found when clotting tests are done for routine screening.
Review Date:
2/28/2011
Reviewed By:
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.
