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. 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. Factor V deficiency is a rare bleeding disorder that affects about 1 in 1,000,000 people. It can involve recurrent nosebleeds, heavy menstrual bleeding and prolonged bleeding after surgery. Factor V (Factor 5) is a protein in your blood that helps form clots when you’re injured. It’s produced primarily by liver cells and plays a central role in the clotting cascade, the chain reaction your body triggers to stop bleeding. Factor V Leiden (rs6025 or F5 p.R506Q[1]) is a variant (mutated form) of human factor V (one of several substances that helps blood clot), which causes an increase in blood clotting (hypercoagulability). 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 is a 330-kDa glycoprotein containing 2196 amino acids. It is synthesized as a single chain molecule in liver and megakaryocytes and circulates in blood as an inactive cofactor. Learn more about the diagnosis and treatment of Factor V Leiden. Find tips to get ready for any appointments you need. 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] 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.