Factor XII (Hageman factor) deficiency

• Illustrations
• Definition
• Causes, incidence, and risk factors
• Symptoms
• Signs and tests

• Treatment
• Expectations (prognosis)
• Complications
• Calling your health care provider
• Prevention

Definition    Return to top

This is an inherited disorder with no symptoms. ItВ does not cause abnormal bleeding in the affected person, but the blood takes longer than normal to clot (coagulate) in a test tube.В It results from a deficiency of the plasma protein factor XII.

Causes, incidence, and risk factors    Return to top

Factor XII deficiency is a rare hereditary disorder that is usually found when clotting tests are done for routine screening. It is not associated with abnormal bleeding.

Symptoms    Return to top

There are usually no symptoms.

Signs and tests    Return to top

• Prolonged partial thromboplastin time
• Abnormal factor XII assay

Treatment    Return to top

Treatment is generally unnecessary.

Expectations (prognosis)    Return to top

The outcome is expected to be good without treatment.

Complications    Return to top

There are usually no complications.

Calling your health care provider    Return to top

This condition is usually discovered by the health care provider when prolonged clotting is noticed in the process of running other laboratory tests.

Prevention    Return to top

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