Factor XII deficiency is an inherited disorder that affects a protein (factor XII) involved in blood clotting.
When you bleed, the body a series of reactions takes place to help the blood clot. This is called the coagulation cascade. Factor XII is a special protein, called a coagulation factor, which helps in this process.
Each factor in the process triggers the next reaction. The final product is the blood clot. There is a higher chance of excess bleeding when one or more of these clotting factors are missing.
A lack of factor XII does not cause you to bleed abnormally. However, 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.
Exams and Tests
Factor XII deficiency is most often found when clotting tests are done for routine screening.