Factor V Leiden is an inherited condition with a risk of thrombosis. Heterozygous If you have one parent with the mutation and you have inherited factor V Leiden from them, your risk of a blood clot is 5 to 7 times higher than normal. Homozygous If both parents have Factor V Leiden and you have inherited two copies of the mutation, your risk of a blood clot is 40 … [Read more...]
Factor V Leiden and the Pill
The oral contraceptive was first introduced in the US in 1960. Within two years, over a million women in the US were taking the “pill” as a safe, effective form of contraception. The use snowballed, and hundreds of millions of women now use oral contraceptives. Some regard it as the most socially significant advance in modern medicine as it gave women reproductive … [Read more...]
Factor V Leiden – What does it mean for me?
What is my risk of a clot? In the general population, the risk of having a blood clot (either a deep vein thrombosis or pulmonary embolus) is quoted at 1 in 2000 people each year. However, the risk is highly dependent on your age. If you are in your twenties the risk is about 1 in 10,000 and if you are over 70 years it is as high as 1 in 200. If you have the factor V Leiden … [Read more...]
Factor V Leiden – What is factor V Leiden?
In the last two posts, I discussed how factor V works and how Protein C controls its activity. In this post, I will look at the difference between Factor V and Factor V Leiden. What is Factor V Leiden? Factor V Leiden is an alternative form of Factor V caused by a small mutation in the factor V gene. First, I will take you through some basic genetics to help you … [Read more...]
Factor V Leiden – Controlling Factor V
I explained how Factor V helped to speed up clotting in my last post. I compared it to pouring petrol on a fire. In this post, I will look at how Factor V is controlled. Clotting is complex but quite precisely controlled. It only takes place when and where you need it. You want the bleeding to stop at the site of the injury when you cut your finger, but you don’t want … [Read more...]
Factor V Leiden – What is Factor V?
In my introductory post about Factor V Leiden, I discussed how this is an inherited condition and relatively common affecting around 4% of people of European decent. In this post I will take you through some of the basics of clotting to help you understand why Factor V Leiden increases your risk of clots. Factor V Factor V Leiden is an abnormal form of the clotting … [Read more...]
Factor V Leiden – A family affair
I see people with blood clots every week, and I am frequently asked, “Why did I get a clot?” Provoked or unprovoked clot In many cases it is obvious why the clot occurred. In approximately 50% of cases, there is a clear provoking factor; The common ones are. Recent surgeryInjury to the legImmobilityLong air flightUnderlying cancer In women Taking an oral … [Read more...]
COVID, clots and Shots – Factor V Leiden and the Pfizer vaccine
Over the last few months, both doctors and patients have asked me several times if it is safe for people with the Factor V Leiden mutation to have the Pfizer COVID-19 vaccine. At first, I couldn't understand why this question would come up, as there is no evidence that the Pfizer vaccine has any risk of thrombosis. But I presume the concern has come from publicity about the … [Read more...]
