Factor XI Deficiency
An inherited shortage of clotting factor XI that can cause excess bleeding
Quick Facts
- Type: Inherited bleeding disorder
- Also called: Hemophilia C
- Main feature: Bleeding after surgery, injury, or dental work
- Bleeding severity: Often unpredictable, varies between people
Overview
Factor XI deficiency, sometimes called hemophilia C, is an inherited bleeding disorder caused by a shortage of clotting factor XI, one of the proteins the body uses to form blood clots. When this factor is low, the blood does not clot as effectively, which can lead to excessive bleeding.
Unlike the more familiar hemophilia A and B, factor XI deficiency often causes milder and less predictable bleeding. Many people have few or no spontaneous bleeding problems and only discover the condition when they bleed more than expected after surgery, dental procedures, or injury. It affects both males and females and is more common in certain populations. With awareness and planning around procedures, most people manage well.
Symptoms
Bleeding tendencies vary widely, and the amount of factor XI in the blood does not always predict how much a person bleeds. Possible signs include:
- Prolonged or excessive bleeding after surgery or dental work
- Heavy or prolonged bleeding after injury
- Frequent or prolonged nosebleeds
- Easy bruising
- Heavy menstrual periods
- Bleeding after childbirth
- Blood in the urine in some cases
Spontaneous bleeding into joints or muscles, which is common in hemophilia A and B, is unusual in factor XI deficiency. Bleeding is often most noticeable in areas with high clot-dissolving activity, such as the mouth, nose, and urinary tract.
Causes
Factor XI deficiency is caused by a change (mutation) in the gene that provides instructions for making clotting factor XI. This genetic change reduces the amount or function of the factor in the blood.
It is usually inherited and can be passed on by either parent, affecting males and females equally. A person may inherit the gene change from one or both parents, which can influence how low their factor XI level is. The condition is more common in some populations, where it occurs more frequently than in the general population. Rarely, low factor XI can develop from another medical condition rather than being inherited.
Risk Factors
- A family history of factor XI deficiency or a bleeding disorder
- Belonging to a population in which the condition is more common
- Inheriting the gene change from one or both parents
- Upcoming surgery or dental procedures, which raise the chance of noticeable bleeding
Diagnosis
Factor XI deficiency is often suspected after unexpected bleeding or an abnormal routine clotting test, and confirmed with specific blood tests.
- Clotting screening tests: Such as the activated partial thromboplastin time (aPTT), which may be prolonged.
- Factor XI activity test: Measuring the level and function of factor XI directly to confirm the diagnosis.
- Tests to exclude other disorders: Checking other clotting factors to rule out similar conditions.
- Family and personal bleeding history: An important part of the assessment.
Treatment
Many people do not need regular treatment and are managed mainly around surgery, dental work, injury, or childbirth. Treatment is tailored to the situation and the person's bleeding history.
- Planning ahead for procedures: Discussing the condition with the surgical or dental team in advance.
- Factor replacement or plasma products: Used to raise factor XI levels before or after significant procedures or major bleeding.
- Antifibrinolytic medicines: Such as tranexamic acid, which help stabilize clots and are especially useful for bleeding in the mouth, nose, or during menstruation.
- Local measures: Pressure and topical agents to control minor bleeding.
Care is often coordinated through a specialized hemophilia or bleeding-disorder treatment center.
Prevention
- Tell all your healthcare providers and dentists about your bleeding disorder before any procedure
- Plan ahead with a specialist before surgery, dental work, or delivery
- Avoid medicines that increase bleeding, such as aspirin and certain anti-inflammatory drugs, unless approved by your doctor
- Carry medical identification noting your condition
- Consider genetic counseling if you are planning a family
When to See a Doctor
See a doctor if you have a personal or family history of unusual bleeding, bleed more than expected after procedures or injury, or have frequent nosebleeds, easy bruising, or heavy periods, so the cause can be evaluated.
Seek emergency care for severe or uncontrolled bleeding, bleeding after a major injury, signs of internal bleeding such as severe pain, dizziness or fainting, or any head injury, as bleeding can be more serious with this condition and may need urgent treatment.
Frequently Asked Questions
Is factor XI deficiency the same as hemophilia A or B?
No. It is a separate disorder, sometimes called hemophilia C, caused by low clotting factor XI rather than factor VIII or IX. It tends to cause milder and less predictable bleeding, and unlike hemophilia A and B, it usually does not cause spontaneous joint bleeding.
Does a low factor XI level mean severe bleeding?
Not necessarily. In factor XI deficiency the level of the factor does not reliably predict how much a person bleeds. Some people with low levels bleed little, while others bleed more, so management is based on a person's actual bleeding history as well as their level.
How is the bleeding treated?
Many people need treatment only around surgery, dental work, injury, or childbirth. Options include factor replacement or plasma products to raise factor XI, and antifibrinolytic medicines such as tranexamic acid, which are helpful for bleeding in the mouth, nose, and during periods.
Is factor XI deficiency inherited?
Yes, it is usually inherited and can be passed on by either parent, affecting males and females equally. It is more common in some populations. Genetic counseling can help families understand the risk of passing it on.
What should I do before surgery or dental work?
Tell your surgeon and dentist about your condition well in advance so they can plan with a bleeding-disorder specialist. Preventive treatment before the procedure can greatly reduce the risk of excessive bleeding.
References
- National Hemophilia Foundation / Bleeding Disorders organizations.
- National Heart, Lung, and Blood Institute (NHLBI).
- MedlinePlus, U.S. National Library of Medicine. Factor XI deficiency.
- World Federation of Hemophilia.