Prothrombin G20210A

Prothrombin G20210A is a genotypic trait that provides a prompter coagulation response. It increases the risk of blood clots including from deep vein thrombosis, and of pulmonary embolism. One copy of the mutation increases the risk of a blood clot from 1 in 1,000 per year to 2.5 in 1,000. Two copies increases the risk to up to 20 in 1,000 per year. Most people never develop a blood clot in their lifetimes.

It is due to a specific gene mutation in which a guanine is changed to an adenine at position 20210 of the DNA of the prothrombin gene. Other blood clotting pathway mutations that increase the risk of clots include factor V Leiden.

Prothrombin G20210A was identified in the 1990s. About 2% of Caucasians carry the variant, while it is less common in other populations. It is estimated to have originated in Caucasians about 24,000 years ago.