The A20210 allele of the prothrombin gene is frequently associated with the factor V Arg 506 to Gln mutation but not with protein S deficiency in thrombophilic families.

Abstract

To the Editor: A genetic variation in the 3′-untranslated region of the prothrombin gene (G to A transition at position 20210) has recently been linked to increased plasma prothrombin levels and an enhanced risk of venous thrombosis.[1][1] The A20210 allele is present in 5.0% to 7.3% of venous