>MTHF

MTHFR is short for methylenetetrahydrofolate reductase, which is an enzyme that is involved in getting and removing homocysteine from the blood. Homocysteine is a toxin that the body likes to break down. In 1988, it was found that some people had a gene change in their MTHFR gene. This was a gene change at position 677. This change meant that if an individual had this change, when they were short of a vitamin called folic acid, they were not so good at metabolizing homocysteine. Sorry this is so complicated!

After it was discovered, there were studies that suggested just maybe this change was associated with increased risk of having blood clots (VTE). This led to the MTHFR test being added to thrombophilia testing. But in actual fact, it wasn't properly validated. In the last five years, we know from beautiful, large, randomized, controlled trials that MTHFR has nothing to do with a higher rate of blood clots.

Indeed, we have learned more than that. We have learned that if we give people with this defect folic acid, it makes no difference to their VTE risk. So I hope you can see that MTHFR testing is therefore not a thrombophilia test. The problem is that lots of labs aren't up to date and they have not removed it from their testing.

The other problem is that the MTHFR change is present in a single dose in 46% of the population, and a double dose of the change is present in 12% of the population. That means over half of the population have got this change! So, we really shouldn't be testing for something that is expensive to test for and is present in normal people.

Here are a few new resources talking about this: https://www.worldthrombosisday.org/news/post/wtd-publishes-new-resources-recommending-mthfr-should-be-removed-thrombophilia-testing-panels/