Vitamin K dependent proenzyme that is part of the blood coagulation cascade.
Deficiency is rare inherited autosomal recessive disorder manifesting a decrease in the synthesis of prothrombin or as dysprothrombinemia with dysfunctional prothrombin.
Homozygotes deficient patients have prothrombin levels of 2-25% and are usually asymptomatic, but they may experience easy bruisability, epistaxis, soft tissue bleeding, postoperative bleeding and menorrhagia.
In heterozygous inherited factor II deficiency, individuals are asymptomatic and have prothrombin levels of 50% or greater on immunologic and functional assays.
In dysthrombinemia the functional assay reveals low prothrombin levels and the immunologic assay is normal.