Leiden Factor V is a condition in which the patient experiences an increased risk for blood clots and, therefore, its related illnesses (such as a higher risk for DVT, pulmonary embolism, stroke, etc). In this disease, the Factor V gene experiences a mutation in the Arg amino group to a Gln, which in turn causes a resistance to Activated Protein C (or APC) and leads to a greater risk for blood clots because their growth and accumulation cannot be hindered by APC (de Stefano et al., 1998). As an interesting fact, this disease of course causes an increased chance for life-altering blood clots, however this mutation has actually been shown to help in preventing blood loss during events such as childbirth, blood transfusions and injuries (Donahue et al., 2003).
I myself inherited this condition from my mother. As far as we are aware, she and I are both heterozygotes for this disease and therefore don’t experience its full effects (she inherited a mutated copy from her father while her mother had a “normal” Factor V, then passed her mutation down to me and the “normal” copy I received from my father as well). While I have- luckily- never experienced an event with this disease, my family have dealt with the condition and it continues to be something I keep an eye on (for example, ensuring I am well-hydrated and not being sedentary for long periods of time, as well as not taking most types of birth control). This condition is more common with those of Caucasian descent (de Stefano et al., 1998), however is still rather rare even among that population, and many carriers may not even know they have this mutation until a life-altering event occurs.
Works Cited
de Stefano, V., Chiusolo, P., Paciaroni, K., & Leone, G. (1998, August). Epidemiology of factor V Leiden: clinical implications. In Seminars in thrombosis and hemostasis (Vol. 24, No. 04, pp. 367-379). Copyright© 1998 by Thieme Medical Publishers, Inc..
Donahue, B. S., Gailani, D., Higgins, M. S., Drinkwater, D. C., & George Jr, A. L. (2003). Factor V Leiden protects against blood loss and transfusion after cardiac surgery. Circulation, 107(7), 1003-1008.
Brooke, thanks for sharing your own personal experience with Leiden Factor V. It's a really interesting disease in how it can increase that positive feedback loop of platelet plug forming, but unfortunately, without an off switch. Given you said that mutation leads to resistance in APC, which, as we know, helps stop our common pathway from occurring, I wonder if the way to treat it (in addition to increased movement, hydration, etc.) would be to prescribe medications that help increase the tPA in the body so that fibrin is broken down more quickly? I do think it's super fascinating that in cases where large quantities of blood may/are lost, this mutation has actually helped them from bleeding too much. It also makes me wonder if someone with both hemophilia and this Leiden factor V would basically cancel each other out. Food for thought!
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DeleteIt's pretty rare, but I think it’s theoretically possible for someone to have both factor V Leiden and hemophilia. Hemophilia causes low levels of factor VIII or IX, making people bleed more easily, while factor V Leiden makes factor V resistant to inactivation and increases clotting risk. If someone had both, the clotting risk from factor V might offset some bleeding, but it wouldn’t cure the hemophilia. I imagine managing both would be really tricky, because treatments to prevent clots could worsen bleeding, and treatment to prevent bleeding could increase clotting risk.