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Factor XI deficiency
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Factor XI deficiency

Factor XI deficiency is a rare bleeding disorder caused by a shortage of the factor XI clotting protein, typically resulting in mild, prolonged bleeding after trauma or surgery.

Overview & Symptoms

Factor XI deficiency is a disorder that causes abnormal bleeding due to a shortage of the factor XI protein, which is essential for blood clotting. The condition is classified as either partial or severe based on the level of the protein deficiency. Regardless of severity, most affected individuals experience relatively mild bleeding symptoms, and some have no symptoms at all.

Common signs and symptoms include:

  • Prolonged bleeding after trauma or surgery, particularly involving the inside of the mouth, nose, or urinary tract
  • Development of congealed blood swellings (hematomas) in surgical areas if untreated
  • Frequent nosebleeds
  • Easy bruising and bleeding under the skin
  • Bleeding of the gums
  • Heavy or prolonged menstrual bleeding (menorrhagia) or prolonged bleeding after childbirth in women

Unlike other severe bleeding disorders, spontaneous bleeding into the urine (hematuria), gastrointestinal tract, or skull is uncommon, and bleeding into muscles or joints generally does not occur.

Frequency

Factor XI deficiency is estimated to affect approximately 1 in 1 million people worldwide. Severe deficiency is significantly more common in individuals of central and eastern European (Ashkenazi) Jewish ancestry, occurring in about 1 in 450 people in that population. The actual prevalence may be higher because mild cases often go undiagnosed.

Causes & Genetics

Most cases of factor XI deficiency are caused by mutations in the F11 gene, which provides instructions for making the factor XI protein. This protein is part of the coagulation cascade, a series of chemical reactions that form blood clots to seal injured blood vessels and stop bleeding.

Mutations in the F11 gene lead to a shortage of functional factor XI, slowing down the clotting process. The severity of bleeding does not always correlate directly with the level of factor XI in the blood, suggesting other genetic and environmental factors influence the condition.

Cases not caused by F11 gene mutations are known as acquired factor XI deficiency. This form can be caused by immune system malfunctions that attack the factor XI protein, severe liver disease (as factor XI is primarily made in the liver), or receiving a liver transplant from an affected individual. Additionally, about 25 percent of individuals with Noonan syndrome also have factor XI deficiency.

Associated Gene

  • F11

Inheritance Pattern

Severe factor XI deficiency is typically inherited in an autosomal recessive pattern, meaning both copies of the F11 gene in each cell have mutations. Parents of these individuals carry one mutated copy, resulting in partial factor XI deficiency, and they rarely show severe symptoms.

In some families, the condition is inherited in an autosomal dominant pattern, where a single mutated copy of the F11 gene in each cell is sufficient to cause the disorder. In these cases, an affected individual typically has one parent with the condition.

The acquired form of factor XI deficiency is not inherited and does not run in families.

Other Names for This Condition

  • F11 deficiency
  • Factor 11 deficiency
  • Haemophilia C
  • Hemophilia C
  • Plasma thromboplastin antecedent deficiency
  • PTA deficiency
  • Rosenthal factor deficiency
  • Rosenthal syndrome
  • Rosenthal's disease

Frequently Asked Questions

The first line is replacement of the missing factor. Factor XI concentrate (if licensed in your country) is given at 30–50 IU/kg, repeated every 12–24 hours until hemostasis. If concentrate is unavailable, fresh frozen plasma (15–20 mL/kg) can be used, but watch for volume overload. Antifibrinolytics such as tranexamic acid (1 g IV over 10 minutes, then 1 g every 8 hours) are adjuncts, especially for mucosal or surgical bleeding. Always involve a hematology specialist for dosing and monitoring.
The key test is a specific factor XI activity assay, which measures the percentage of functional Factor XI in plasma. A prolonged activated partial thromboplastin time (aPTT) may be seen, but it can be normal in mild cases. If aPTT is prolonged, a mixing study helps differentiate a factor deficiency from an inhibitor, and then a factor XI assay confirms the diagnosis. Genetic testing of the F11 gene can also identify the mutation, especially in families with known deficiency.
Inform your dentist and surgeon about the diagnosis well in advance. For minor dental work, many clinicians use local measures (tranexamic acid mouthwash, fibrin sealants, and pressure dressings) without systemic therapy. If your Factor XI activity is <20 IU/dL or you have a history of excessive bleeding, a pre‑procedure dose of plasma‑derived Factor XI concentrate (if available) or fresh frozen plasma (15 mL/kg) can be given 30–60 minutes before the procedure. Post‑procedure, continue tranexamic acid (1 g orally every 8 hours) for 3–5 days.
Combined oral contraceptives (estrogen‑progestin) or progestin‑only methods can reduce menstrual blood loss by stabilizing the endometrial lining. They are generally safe in Factor XI deficiency because they do not increase clotting risk. However, if you have a personal or family history of thrombosis, discuss alternatives (e.g., levonorgestrel IUD) with your gynecologist. If bleeding remains severe, a short course of tranexamic acid during menses (1 g three times daily) can be added.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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