What Is Factor II Deficiency? 

Factor II (prothrombin) deficiency is an inherited bleeding disorder caused by a defect or lack of a protein in the blood (factor II) that helps blood clot. It is very rare, affecting one out of  2,000,000 people. Factor II deficiency is passed from parent to child and is an autosomal recessive disorder, meaning that both parents must carry the defective gene in order to pass it on to their child and that it affects both males and females.

In factor II deficiency, there is a lower than normal amount of prothrombin in the blood, or the prothrombin does not function properly. Normally, factor Xa, another blood clotting protein, converts prothrombin to thrombin which, in turn, continues a complex clotting chain reaction that ultimately results in a clot. Without prothrombin, the process stops prematurely and a clot does not form.

Factor II deficiency may also be acquired later in life. Severe liver disease can slow down or stop prothrombin production. Some blood thinners such as coumadin or vitamin K deficiency may also interfere with production of prothrombin. Acquired factor II deficiency is more common than the inherited form.

Symptoms

People with factor II deficiency may experience:

• bleeding from the umbilical cord stump at birth
• easy bruising
• nose bleeds
• heavy or prolonged bleeding during menstrual periods (menorrhagia)
• abnormal bleeding during or after surgery, dental work, or childbirth
• occasional bleeding into muscle

Diagnosis

Factor II deficiency is diagnosed by a variety of blood tests to see if there is a bleeding disorder and, if so, to determine which one it is.

Treatment

Factor II deficiency is treated with:

• clotting factor concentrates which contain factor II
• prothrombin complex concentrates (PCCs)
• fresh frozen plasma (FFP)

Content reviewed by Dr. Paula Bolton-Maggs
Consultant Haemotologist
Manchester Haemophilia Comprehensive Care
Manchester Royal Infirmary
Manchester, UK.

Last updated December 2007