An inherited blood-clotting disorder due to a mutation of the blood's factor V protein.
Factor V Leiden increases the chance of clumps of blood (clots) developing, which can be life-threatening. Women with the disorder risk developing blood clots during pregnancy or when taking the hormone estrogen.
Most people never develop symptoms. However, the first indication of the disorder may be the development of a blood clot (thrombosis).
Treatment may include blood-thinning drugs.