Thrombophilia is the increased tendency to develop thrombi (blood clots) because of an abnormality in the clotting system. A range of genetic variations that are inherited at birth alter the haemostasis mechanisms in the blood and increase the chances of DVT and PE.

Common thrombophilia genetic variants are ‘Factor V Leiden’ and ‘Prothrombin 20210’, both of which change the way blood clots.