Factor XI Deficiency

National Organization for Rare Disorders, Inc.

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It is possible that the main title of the report Factor XI Deficiency is not the name you expected.

Disorder Subdivisions

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General Discussion


Factor XI deficiency is a rare genetic bleeding disorder caused by reduced levels and insufficient activity of a blood protein called factor XI. Factor XI is a clotting factor. Clotting factors are specialized proteins that are essential for proper clotting, the process by which blood solidifies like glue to plug the site of a wound to stop bleeding. Individuals with factor XI deficiency do not bleed faster or more profusely than healthy individuals, but, because their blood clots poorly, they may have difficulty stopping the flow of blood from a deep or surgical wound. This may be referred to as prolonged bleeding or a prolonged bleeding episode. The severity of factor XI deficiency can vary from one person to another. In many cases, prolonged bleeding episodes only occur after surgery, dental procedures or trauma. Bleeding tendencies in factor XI deficiency are unpredictable and inconsistent, making the disorder difficult to manage in some cases. Factor XI deficiency is caused by disruptions or changes (mutations) to the F11 gene. Factor XI deficiency is inherited autosomally and can occur in people of either sex.


Factor XI deficiency was first described in the medical literature in 1953. It used to be also referred to as hemophilia C in order to distinguish it from the better known hemophilia types A and B. In rare cases, factor XI deficiency can be acquired during life (acquired factor XI deficiency). This report deals with the genetic form. Although the genetic form is present at birth, as it is a mild bleeding disorder symptoms do not usually occur until later in life.

Supporting Organizations

Canadian Hemophilia Society

301-666 Sherbrooke Street West
Montreal, QC H3A 1E7
Tel: 5148480503
Fax: 5148489661
Tel: 8006682686
Email: chs@hemophilia.ca
Website: http://www.hemophilia.ca

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
Website: http://rarediseases.info.nih.gov/GARD/

Hemophilia Federation of America

210 7th St. SE
Suite 200B
Washington, DC 20003
Tel: (202)675-6984
Fax: (202)675-6983
Tel: (800)230-9797
Email: info@hemophiliafed.org
Website: http://www.hemophiliafed.org

NIH/National Heart, Lung and Blood Institute

P.O. Box 30105
Bethesda, MD 20892-0105
Tel: (301)592-8573
Fax: (301)251-1223
Email: nhlbiinfo@rover.nhlbi.nih.gov
Website: http://www.nhlbi.nih.gov/

National Hemophilia Foundation

116 West 32nd Street, 11th Floor
New York, NY 10001
Tel: (212)328-3700
Fax: (212)328-3777
Tel: (800)424-2634
Email: handi@hemophilia.org
Website: http://www.hemophilia.org

World Federation of Hemophilia

1425, boul. René-Lévesque O.
Bureau 1010
Montréal, Québec, H3G 1T7
Tel: +1 (514) 875-7944
Fax: +1 (514) 875-8916
Email: wfh@wfh.org
Website: http://www.wfh.org/en/page.aspx?pid=492

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

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This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  8/28/2012
Copyright  2012 National Organization for Rare Disorders, Inc.