Prothrombin (Factor II) Deficiency

Pattern of Inheritance

Hypoprothrominemia and dysprothrombinemia are both inherited as autosomal recessive traits.17,26 Many of the patients who have been genotyped are homozygous for the same prothrombin mutation, rather than being compound heterozygotes. More than 50 different mutations have been identified in patients with prothrombin deficiency, with the majority of these genetic defects being attributed to missense mutations. For instance, in one genetic analysis of mutations causing rare bleeding disorders, ~78% of 54 patients with prothrombin deficiency were found to have missense mutations.14 Nonsense, splicing error, and deletion/insertion mutations have also been reported. The Rare Bleeding Disorders Network ( and the International Society on Thrombosis and Haemostasis ( are international registries that contain information on gene mutations associated with various RBDs, including prothrombin deficiency.