Factor X deficiency is a disorder caused by too little of a protein called factor X in the blood. It leads to problems with blood clotting (coagulation).

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 X is a coagulation factor.) Each factor's reaction triggers the next reaction. The final product of the coagulation cascade is the blood clot. When certain coagulation factors are missing, the chain reaction does not take place normally.

Factor X deficiency is often caused by a defect of the factor X gene that is passed through families. This is called inherited factor X deficiency. Bleeding ranges from mild to severe.

Factor X deficiency may also develop due to another condition or use of medications. This is called aquired factor X deficiency. Acquired factor X deficiency is common. It may be caused by a lack of vitamin K, amyloidosis, severe liver disease, and use of drugs that prevent clotting (anticoagulants such as warfarin or coumadin). Some newborns are born with vitamin K deficiency. See: Vitamin k deficiency bleeding in newborns

Women with factor X deficiency may have very heavy menstrual bleeding and bleeding after delivery. Newborn boys with the condition may have longer-than-normal bleeding after circumcision.

Inherited factor X deficiency affects 1 out of every 500,000 people.

• Nosebleeds (epitaxis)
• Bleeding into joints
• Muscle bleeding
• Mucous membrane bleeding

• Prolonged prothrombin time
• Prolonged partial thromboplastin time
• Low factor X activity
• Normal thrombin time

Treatment for the bleeding disorder involves infusions of fresh frozen plasma or factor X concentrates into the blood during sudden (acute) episodes or before surgery.

You can ease the stress of illness by joining a support group where members share common experiences and problems.

See: Hemophilia - resources

The outcome is usually good with mild disease or treatment.

Inherited factor X deficiency is a life-long condition.

The outlook for acquired factor X deficiency depends on the underlying cause. If it is caused by liver disease, the outcome depends on how well your liver disease is controlled. Taking vitamin K supplements will treat vitamin K deficiency. If the disorder is caused by amyloidosis, surgery is done to remove the spleen.

Severe bleeding or sudden loss of blood (hemorrhage) can occur. The joints may get deformed in severe disease from many bleeds.

Call your health care provider, go to the emergency room, or call the local emergency number (such as 911) if you have an unexplained or severe loss of blood.

Inherited factor X deficiency is rare. There is no known prevention.

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

Takabe K, Holman PR, Herbst KD, Glass CA, Bouvet M. Successful perioperative management of factor X deficiency associated with primary amyloidosis. J Gastrointest Surg. March 2004;8:358-362.