I have Factor V Leiden (FVL) heterozygous mutations (rs6025) plus the FV R2 heterozygous mutation (rs180059). FVL heterozygous by itself increases the risk of thrombosis by 3.5-4.4X. The combined FVL plus FV R2 compound heterozygous mutation makes one significantly more prone to blood clots.
23andme had both of these called correctly for me and confirmed by my doctor with a medical lab. If 23andme tested you for both of these, then going into raw data and typing in F5 should pull up your list of F5 gene location calls.
That FV R2 mutation by itself (without FVL mutation) is usually thought of as making one bleed easier. In theory, it reduces the amount of Factor V produced by the body, and since Factor V helps with clotting, having less of it reduces how easily someone clots. Yet, as we know the body generally has overlapping safeguards so it's not quite reduced in half.
What they found is that people who have FVL and that FV is more clotty, and then they don't produce any other FV (FV R2 mutation) -- therefore, all the FV produced is clotty.
This article in the American Society of Hematology's journal Blood, does a much better job explaining it than I.
http://www.bloodjournal.org/content/94/9/3062?sso-checked=true
My hematologist has me on two low dose aspirins a day for this. I know the symptoms of when I'm more clotty, and during those times I'll up my daily low dose aspirin to 3. I also know how my body reacts to too much aspirin, and I cut down on the aspirin when my teeth bleed upon brushing or when I slightly bump into something and it hurts like the dickens.
There is a blood test that my hematologist gives me every once in a while to make sure I'm not taking too much aspirin for my body.
I didn't pass the compound heterozygous mutations to the kids. I did pass the FVL heterozygous down to one of our children with mitochondrial disease. She often has severe pins and needles in her feet like I do. None of the other kids with MitoD have the pins and needles in their feet to the extent the two of us with FVL do. When I am good with taking my aspirins, it really helps with my pins and needles in my feet.
One of our children doesn't have the FVL mutation, but does have the FV R2 mutation. That child gets severe nose bleeds, which makes sense given that child has half (or somewhat less) Factor V clotting in the blood.
I believe a lot of genetics is this complex. This is why the researchers are going for the easier pickings of looking for mutations that cause X disease. But for every one of those easy picking mutations, there are many others that are more complex. I have no doubt they'll get around to how all the mutations interact, but not this year.
