Factor V Deficiency
What is factor V deficiency?
People with factor V (5) deficiency have low levels of factor V, one of the clotting factor proteins that helps to produce thrombin and impact formation of a stable blood clot. Without thrombin, the body cannot form a stable clot to stop the bleed.
Recently, an international organization (International Society on Thrombosis and Hemostasis) proposed a classification of factor V severity based upon factor activity and associated symptoms, although the connection between factor activity and symptoms is much less strong in inherited factor V deficiency than hemophilia A (factor VIII (8) deficiency) or B (factor IX (9) deficiency):
- Mild (≥ 10% activity): Patients are mostly asymptomatic, but might have problems with bleeding during trauma, a surgical procedure or with pregnancy/delivery
- Moderate (< 10% activity): Patients may have mild spontaneous bleeding, or bleeding triggered by trauma, surgery, or pregnancy/delivery
- Severe (undetectable activity): Patients may have spontaneous, severe, and even life-threatening bleeding
What causes it?
Factor V deficiency is a recessive disorder, meaning you need both your parents to pass on an affected gene in order to get the disease. If you get only one copy of the gene, you can be a carrier and pass the gene to your children. It affects about 1 in every 1 million people, and occurs in men and women. It can also develop as you get older.
What are the symptoms?
Signs and symptoms, from most to least common, include:
- Easy bruising
- Heavy or prolonged menstrual bleeding (menorrhagia)
- Bleeding in the mouth, particularly after dental surgery or tooth extraction
- Inability to straighten or bend a joint normally
- Headache or muscle or neck ache
- Tight and shiny appearance of skin
- Upset stomach
- Vomit that is black and syrupy or bright red or coffee grounds in appearance
- Red- or black-colored stool
- Blood in the urine
- Prolonged bleeding after childbirth
- Bleeding into a joint (swelling, pain, or warmth around a joint)
- Bleeding into the brain (drowsiness, loss of consciousness, weakness)
How is it diagnosed?
Factor V deficiency is diagnosed by a variety of blood tests starting with screening tests that evaluate the way your blood clots, then progressing to very specific tests that measure the amount of factor V in the blood. It is also important to measure the amount of factor VIII, since there is sometimes a combined deficiency of both factors V and VIII.
How is it treated?
Treatment for factor V deficiency is usually only needed for severe bleeds or before surgery. There are no specific plasma-derived treatments with just factor V. In addition, excessive menstrual bleeding in women with factor V deficiency may be controlled with hormonal therapy (oral or local) and drugs that prevent breakdown of blood clots (anti-fibrinolytic drugs).