Factor V Leiden

Factor V Leiden is also known as the Leiden mutation. It is an inherited disorder of blood coagulation. Factor V Leiden is a common condition, which is risky especially for young girls using hormonal contraception.


The cause of the Leiden mutation is a congenital disorder of blood coagulation system resulting in increased tendency to blood clotting (so-called thrombophilia). As the disease is inherited, it usually has a positive family history.


The coagulation system (or coagulation cascade) is a complex set of multiple proteins. If there is a damage of a blood vessel and bleeding, the coagulation system activates and tries to help the platelets to stop the bleeding. The proteins of coagulation systems activate each other and all these reactions result in transformation of inactive protein fibrinogen to its active form known as fibrin. The fibrin has a ne-like structure; it binds to platelets and helps to stabilize a blood clot (thrombus). And why is there such a complicated system just to allow the formation of fibrin? It is because a complex system can be better regulated. If the fibrin molecules were formed uncontrollably, it would have fatal consequences causing excessive occurrence of blood clots. Factor V Leiden mutation affects one protein of the coagulation cascade (protein number five) causing its excessive activity and thus increased blood clotting.


The symptoms of Factor V Leiden are its thrombotic complications. The patients have increased risk of thrombophlebitis, a deep vein thrombosis and pulmonary embolism. The risk of thrombosis is higher in smokers and in women using the oral contraceptives.


Leiden mutation can be confirmed by a special molecular genetic testing.


The prevention is an extremely important issue. There is increased risk of complications in females using the hormonal contraception. Therefore, the prescribing doctor should always ask if the woman has a positive personal or family history of a thrombosis. It is very advisable for every person with Leiden mutation not to smoke, or to cease smoking.


Leiden mutation can not be cured as it is inborn genetically determined disorder. The treatment therefore focuses on solving possible thrombotic complications by anticoagulation drugs. Once a person has confirmed diagnosis of the Leiden mutation, he or she should tell this fact to the doctors before any planned operation.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources