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Factor XII (Hageman factor) deficiency - All Information

Definition of 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. 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.

Tests may include:

Factor XII assay
Partial thromboplastin time (PTT)

Treatment:

Treatment is usually not needed.

Expectations (prognosis):

The outcome is expected to be good without treatment.

Complications:

There are usually no complications.

Calling your health care provider:

The health care provider usually discovers this condition after noticing prolonged clotting in the process of running other laboratory tests.

Prevention:

This is an inherited disorder. There is no known way to prevent it.

Blood clots

Reviewed last on: 2/28/2011
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.

References

Gailani D, Neff AT. Rare coagulation factor deficiencies. In: Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds. Hoffman Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingstone Elsevier;2008:chap 127.

Kessler C. Hemorrhagic disorders: Coagulation factor deficiencies. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 180.

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