Factor II Deficiency

What is factor II deficiency?

Factor II (2) deficiency (also called prothrombin deficiency) means someone does not have enough factor II, which is a clotting factor protein called prothrombin. When the protein, prothrombin, is activated to make thrombin, this helps change fibrinogen (factor I) into fibrin, which is needed to form a stable clot.

Recently, an international organization (International Society on Thrombosis and Hemostasis) proposed a classification of factor II deficiency severity based upon factor activity and associated symptoms, with a few exceptions.

  • 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 II 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 2 million people, making it one of the rarest clotting factor disorders, and occurs in men and women. Studies have shown a higher incidence of factor II deficiency among Latinos.

What are the symptoms?

  • Swelling, pain, or warmth around a joint
  • Inability to straighten or bend a joint normally
  • Easy bruising
  • Bleeding from the nose, gums, or uterus
  • Bleeding after surgery
  • Headache or neck ache
  • Drowsiness or loss of consciousness
  • Upset stomach 
  • Vomiting that is black and syrupy or bright red or coffee grounds in appearance
  • Red- or black-colored stool
  • Sensitivity to light

In newborns with factor II deficiency, hematomas are seen as well as bleeding from the umbilical cord or after circumcision.

How is it treated?

There are plasma-derived treatments available for factor II deficiency that replaces the missing factor, but there are no specific concentrates that have just factor II. In addition, excessive menstrual bleeding in women with factor II deficiency may be controlled with hormonal therapy (oral or local) and drugs that prevent breakdown of blood clots (anti-fibrinolytic drugs).