You get your bloodwork back and your homocysteine is elevated. If you've ever looked at Instagram ever your first thought is probably "It must be MTHFR!" You might be right, especially if you have an MTHFR C677T variant, which is most closely associated with high homocysteine. But there are many other reasons for homocysteine to be elevated, so don't stop looking once you see MTHFR.

MTHFR gene variants and hypothyroidism are often found together and several studies have looked at the link between the two, but the only real conclusion we can draw is that the connection is not simple. A 2022 meta-analysis published by Yang et. al. shows that C677T variants are associated with an increased risk of hypothyroidism, while A1298C variants are associated with a lower risk than the average population.