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MTHFR discrepancies


I tested my MTHFR genes about 8/9 years ago and it said I was hetro for C677T and A1298C

and now I just got my SNPs results back from Dr Amy Yasko and now it is saying I don't have C677T, just A1298C!

How can there be discrepancies? do I need to worry?

TIA :)


Senior Member
From my understanding of this, gene expressions aren't always fixed and environmental factors play a role in how certain ones are activated or silenced (epigenetics) not sure if this assessment is totally accurate.

I think the discrepancy is fascinating though and hopefully others will chime in as to why it may have occurred.


Senior Member
How can there be discrepancies?

Laboratories make mistakes.

do I need to worry?

No. Both of these SNPs are very common - billions of people live with them without problems.

Both slow the MTHFR enzyme to some extent, the C677T SNP more so than A1298C.

Because of the discrepancies in your results it is not possible to say to what extent this applies in your case. The worst possible situation would be if you are compound heterozygous for the two SNPs - ie one SNP is on one DNA strand and the other is on the other strand. This is the equivalent of being +/+ for C677T.

If this is the case then your enzyme would be slowed to about 30% of normal. This might sound a lot but actually about 9% of the global population is +/+ for C677T. Billions of people function perfectly well with this level of activity. Problems can arise when there is increased demand for folate such as during pregnancy.

The rare pathogenic MTHFR SNPs reduce enzyme activity to less than 10%; this does cause serious problems though they can be overcome readily.

The best possible situation is that you are +/- for A1298C only. This would have a negligible effect on the enzyme, one that is shared with 42% of the global population.

With either possibility there is nothing to worry about - just ensure your folate intake is adequate. Eat plenty of vegetables and consider modest supplementation with either methylfolate or folinic acid.

Note the discrepancies have nothing to do with epigenetics, as suggested above. These tests are simply looking at the actual genetic code in DNA - not epigenetic changes.
There was a recent study finding that there were frequent errors in direct-to-consumer (DTC) genetic tests like 23andme.

I presume the clinical genetic tests used by medical professionals are more accurate than DTC tests, but I am not entirely sure.
That’s quite disturbing to read. Why is the error taking place? Or, rather, how...