Factor II deficiency

Factor II (FII) deficiency, also called prothrombin deficiency, was first identified in 1947 by Dr. Armand Quick. The incidence is estimated at 1 in 2 million in the general population. Factor II deficiency is inherited in an autosomal recessive fashion, meaning that both parents must carry the gene to pass it on to their children; it affects men and women equally.

Prothrombin is a precursor to thrombin, an enzyme that converts fibrinogen into fibrin to strengthen a clot. Dysprothrombinemia results when there is an abnormality in the structure of prothrombin. Hypoprothrombinemia occurs when the body doesn’t produce enough prothrombin. Symptoms include excessive umbilical cord bleeding, easy bruising, frequent nosebleeds and hemorrhaging after surgery or trauma. Women with FII deficiency experience menorrhagia, heavy menstrual bleeding, and postpartum hemorrhage after childbirth. Joint bleeding is uncommon.