What is Heterozygous Factor V(5) Leiden Mutation?

CC courtesy of Valerie Everett, Flickr

As promised I'm going to try and explain what this genetic mutation is. Before I can explain what is actually 'wrong' with me I'll need to give you all some background information - I'm sure you remember you school days biology.

How Clotting Works - Background Information

The body's clotting mechanism is triggered when there is trauma to a blood vessel. The liver will make and release a variety of clotting factors into the blood stream along with platelets from bone marrow (made and released in the pelvis and breast bone). These clotting factors and platelets will then travel to the the damaged area where they will interact with each other and form a blood clot to repair the wall of the blood vessel. Once the damage is repaired the liver will make and release anticoagulants (clot busting enzymes) that travel to the clot, bind to it, break it down (dissolve it) and normal blood flow returns. 

What is Heterozygous FVL?

The naturally occurring anticoagulant Protein C works by attaching to a receptor on the surface of one of the clotting factors known as Factor V (there are 13 in total); this is part of the dissolving processes of a blood clot. The FVL mutation is a genetic condition associated with an alteration of the receptor on the surface of Factor V meaning it is relatively resistant to the effects of Protein C: it takes longer to break down the blood clot - imagine trying to put to bits of jigsaw together that don't quite match.

FVL was discovered in the 1990's in a town called Leiden in Holland. Heterozygous means that there is 1 inherited abnormal gene from 1 parent and one normal gene from the other. This form of FVL is seen in 5-8% of the UK population. It is inherited in a autosomal dominant fashion meaning that your own children will have a 50% chance of having the abnormality.

What are the Risks?

Being heterozygous for FVL increases the risk of blood clots by 5-fold, for women on the oral contraceptive that increases to 34-fold. The greatest risk of a DVT is after surgery and long haul flights.

What is the Treatment?

Compression stocking if you've already had a DVT, you're going in for surgery, or if you're going on a long haul flight. You may also need to take daily doses of an anticoagulant, which slows down the body's ability to clot. I personally need to take Warfarin for the rest of my life as well due to my previous medical history.

So there we go, as promised, my explanation of Heterozygous Factor V Leiden Mutation. I hope your brains haven't turned to mush. If you have any questions leave me a comment and I'll answer as best I can.