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.