Healthcare professionals most often prescribe blood-thinning medicines to treat people who get blood clots. People who have the factor V Leiden gene change but who have not had blood clots don't need this medicine. Factor V Leiden is the most common inherited form of thrombophilia. Between 3 and 8 percent of people with European ancestry carry one copy of the factor V Leiden mutation in each cell, and about 1 in 5,000 people have two copies of the mutation. Factor V is an essential blood-clotting protein that plays a supporting but critical role in normal coagulation. It is also known as Proaccelerin or Labile Factor. When Factor V levels or activity are reduced, the clotting process becomes inefficient, and bleeding may last longer than expected. Most people with factor V Leiden never get harmful clots. But people who do get them need to take blood thinners. Blood clots can lead to long-term health issues. And they can be life-threatening. People assigned male at birth or female at birth can have factor V Leiden. Factor V, or proaccelerin, is a protein made in your liver that helps convert prothrombin into thrombin. This is an important step in the blood clotting process. If you don’t have enough factor V. “Coagulation factor V” is the name of a protein that helps your blood clot when needed, like after an injury. Your F5 gene tells your body how to make this protein. We’ll be taking a deep dive into Factor V Leiden, exploring what it is, who is at risk, and how it can be treated. Our goal is to help demystify this condition and provide a comprehensive guide to living with Factor V Leiden. Coagulation factor V (Factor V), also less commonly known as proaccelerin or labile factor, is a protein involved in coagulation, encoded, in humans, by F5 gene. [5] Factor V (factor 5) is one of several special proteins in your blood that help it clot. They're called clotting factors. Once the bleeding stops, other proteins tell your clotting factors to. An overview of symptoms, genetics, and treatments to help you understand factor V deficiency. Factor V (FV) deficiency was first described in a Norwegian patient in 1943 and reported by Dr. Paul Owren in 1947. Its incidence is about 1 in 1 million; fewer than 200 cases have been documented worldwide.