It is a point mutation of the prothrombin gene at the site G 20210 A discovered in 1996 and is the second most common cause of familial thrombophilia. The risk of these hereditary carriers is 2.8 times higher than the risk of thrombosis. The cause of thrombophilia is the constant hyperprothrombinaemia of over 115% and thus an increased formation of thrombin.
The incidence in Southern Europe is about twice as high as in Scandinavia.
In patients who have undergone thromboembolic events, this defect is found in 15%. If this defect is combined with other thrombophilic diatheses, the risk increases many times over. The diagnosis is made directly by determining the prothrombin concentration and DNA analysis with a PCR.