MTHFR C677T + A1298C compound heterozygous
One copy each of MTHFR C677T and A1298C detected (compound heterozygous).
You have one copy each of the two most-talked-about MTHFR DNA changes — one C677T and one A1298C.
Despite a great deal of online attention, mainstream medical genetics organisations do not recommend acting on this finding. The compound state reduces enzyme activity somewhat below either single variant, but most people with adequate folate intake have no clinical impact.
Despite a lot of online attention, the main medical genetics organisations don't recommend changing anything based on this finding. The combination slightly lowers an enzyme's activity, but for most people with a normal folate intake there's no real-world effect.
What this means
The compound C677T/A1298C state is sometimes described as more impactful than either alone. Enzyme activity is modestly reduced. Whether this translates into meaningful clinical consequences for healthy adults remains contested, and the American College of Medical Genetics recommends against routine MTHFR testing. We include this match because patients ask about it, not because it should drive medical decisions.
Having one of each MTHFR change is sometimes described online as more serious than having either one alone. The combination does modestly lower the activity of an enzyme that helps process folate. Whether that actually causes any real problems in healthy adults is hotly debated, and the American College of Medical Genetics specifically recommends against routine MTHFR testing. We include this finding because so many people ask about it — not because it should change anything you do.
Caveats
- Mainstream genetics organisations explicitly recommend against routine testing or supplementation based on MTHFR genotype.
- Population-level folate fortification largely neutralises the metabolic impact.
- Claims of broad clinical effects (fatigue, depression, miscarriage) are not supported by good-quality evidence.