Thrombophila
<p>Although the risk of developing a thrombus because of factor V Leiden is significantly less than the risk associated with antithrombin III, protein C, and protein S deficiencies, <b>factor V Leiden is the most common inherited</b> cause of VTE because of its <b>more frequent occurrence</b> in the general population. 
 
In one large study, the lifetime probability of developing thrombosis was               8.1 times higher for carriers of antithrombin deficiency, 
           7.3 times higher for protein C deficiency, and 
           8.5 times higher for protein S deficiency compared with individuals without these disorders. 
 
For factor V Leiden, the risk has been reported to be 2 to 4 times higher than for non-carriers.
 
The risk of thrombosis with the prothrombin 20210 mutation is not clear because of its infrequent occurrence. </p>