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How To Interpret Your MTHFR Results From DNA Raw Data

Does 23andMe test for MTHFR?

The 23andMe MTHFR gene test is one of the most sought-after,  requested by many 23andMe customers.

23andMe tests for thousands of single nucleotide polymorphisms and this includes the well known MTHFR gene mutations.

How to find MTHFR on 23andMe?

23andMe provides your genomic information in the form of raw data that can be easily accessed and then uploaded onto sites like Xcode Life to find out the specific variant carried.

23andMe MTHFR results for rs1801133 (MTHFR C677T)

AA2 copies of the variant allele, reduction in MTHFR enzyme activity by nearly 80%
AG1 copy of the variant allele, reduction in MTHFR enzyme activity by 40%
GGBoth normal alleles, no reduction in enzyme activity due to this polymorphism

23andMe MTHFR results for rs1801131 (A1298C)

GG2 copies of the variant allele, reduction in MTHFR enzyme activity
GT1 copy of the variant allele, reduction in MTHFR enzyme activity
TTBoth normal alleles, no reduction in enzyme activity due to this polymorphism

Apart from 23andMe, raw data from companies like AncestryDNA.com, FTDNA.com, and other similar genetic testing service providers may be uploaded to find out more about your MTHFR gene mutations.

Let us find out more about this gene mutation and how it is associated with your health.

What is MTHFR?

The methylenetetrahydrofolate reductase (MTHFR) gene carries instructions for the synthesis of an enzyme with the same name.  

This important enzyme is associated with the processing of amino acids, which are the building blocks for protein molecules.

In the MTHFR pathway, the enzyme converts  5,10-methylenetetrahydrofolate into 5-methyltetrahydrofolate.

This is one of the steps in the process that converts the ‘ harmful’ amino acid homocysteine to the ‘useful’ amino acid, methionine.

Learn about all the genes covered in the MTHFR raw data analysis report

What is the 23andMe MTHFR test?

The MTHFR test has become increasingly popular because of all the awareness currently being generated by widespread DNA testing.

The test is used to identify mutations in two specific regions of the MTHFR gene- C677T and A1298C that are associated with the level of activity of the MTHFR enzyme and the corresponding ability to utilize folate.

The 23andMe MTHFR test will help in identifying the level of MTHFR enzyme activity, which in turn corresponds to how well homocysteine is metabolized and converted into methionine.  

This is necessary for the synthesis of DNA, serotonin and melatonin.

Vitamin B9 (Folate) is vital as it is necessary in the production of all cells.

It is required for DNA synthesis, tissue growth during pregnancy, cell division, immune system, blood formation and other important physiological functions.

How common are the MTHFR 23andMe mutations?

23andMe MTHFR mutation prevalence in the U.S,

MTHFR C677T mutation is the most common and is found at a higher frequency in certain ethnic populations.

  • 20% to 40% of white and Hispanic people are found to be heterozygous to this MTHFR gene
  • 1%–2% among blacks

23andMe MTHFR mutation prevalence in North America, Australia and Europe

  • 8% to 20% are homozygous for  MTHFR C677T
  • 7% to 12% have the 23andme MTHFR A1298C mutation

What is the difference between 23andMe MTHFR test and AncestryDNA MTHFR test?

ContentsMTHFR status from 23andme raw dataMTHFR status from Ancestry DNA raw data
Raw data23andme raw data can be downloadedAncestry DNA raw data can be downloaded
MTHFR C677T and A1298C23andme MTHFR test includes these two SNPsAncestryDNA MTHFR test includes these two SNPs
MTHFR test cost23andme test cost is $99Ancestry DNA test cost is $99 (with a 10% discount on offer currently)
MTHFR test report23andme report does not include information on MTHFR gene. Information is present as raw data which needs interpretation.Ancestry report does not include information on MTHFR gene. Information is present as raw data which needs interpretation.
MTHFR gene report from Alternate providersA variance report generated using 23andme raw data V5 chip has less number of SNPs compared to ancestry DNA.A variance report generated using Ancestry DNA raw data has more number of SNPs compared to 23andme V5 chip.

How can the MTHFR gene testing provided by 23andMe be used to determine health risk?

Here are a few studies which show an association with various health conditions among people with the variant alleles.

  • Association of MTHFR gene polymorphism with cardiovascular disease
    In a large meta analysis conducted on over 40 studies that included 11162 cases and 12758 controls, individuals with the TT genotype(C677T) were associated with a higher risk for CVD.
  • Association of MTHFR gene polymorphism with Breast Cancer risk
    There are two ways that the 23andme MTHFR gene polymorphisms could influence cancer risk.
    In the MTHFR pathway, the substrate of MTHFR enzyme, 5,10- methylenetetrahydrofolate, is associated with the synthesis of deoxythymidylate monophosphate from deoxyuridylate monophosphate.
    When the amount of  5,10-methylenetetrahydrofolate is reduced, it could affect the ratio of deoxyuridylate monophosphate/deoxythymidylate monophosphate.
    This in turn would increase the addition of uracil, instead of thymine, resulting in the increased risk for point mutation and breakage of DNA.
    An alternate mechanism for an increase in breast cancer risk is by the level of methionine, as this amino acid is necessary for maintaining methylation patterns in DNA.
    meta analysis showed that people with the TT genotype were associated with an increased risk for breast cancer.
  • Association of MTHFR gene polymorphism with Venous thromboembolism
    Deep vein thrombosis or pulmonary embolism is one of the major risk factors of morbidity and mortality among older adults.
    Among 70 individual studies, it was found that people with the TT genotype had higher homocysteine levels, thereby increasing their risk for deep vein thrombosis.
  • Association of MTHFR gene polymorphism with Autism spectrum Disorders  
    DNA methylation is associated with tissue-specific gene expression imprinted gene expression and chromatin structure.
    The 23andMe MTHFR (C677T and A1298C) have been found to alter the enzyme activity, which has been shown to affect neurological development. 
    Children with the C677T variant were associated with an increased risk of autism spectrum disease in countries where the food was not fortified with folate.
  • Association of MTHFR gene polymorphism with neural tube defects
    Neural tube defects are among the most common congenital malformations.
    In a meta analysis 40 studies were taken into consideration and it was found that mother’s with the C677T variant were associated with an increased risk for neural tube defects.

How to interpret 23andme raw data MTHFR mutations?

The MTHFR 23andme results can be used to interpret the level of enzyme activity, which in turn can be used to identify the extent of folate supplementation required.  

Though it has been shown that reduced MTHFR enzyme function is associated with elevated homocysteine levels, many people have normal homocysteine levels, especially in places like the United States where there is a fortification of food with folic acid.

Who should take up the MTHFR 23andme test?

According to the NIH, there are over 40 mutations in the MTHFR gene that are associated with poor enzyme activity and associated increase in homocysteine levels in the body.

Certain genetic testing companies check for only the two major MTHFR gene mutations, while there are many others, like us, who give you a detailed report based on the 23andme MTHFR variants present in the 23andme raw data.

The Xcode Life MTHFR report covers several of these genetic variations covered in the NIH publication above.


  1. http://circ.ahajournals.org/content/132/1/e6
  2. https://www.ncbi.nlm.nih.gov/pubmed/26629412
  3. https://www.ncbi.nlm.nih.gov/pubmed/25808073

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6 comments on “How To Interpret Your MTHFR Results From DNA Raw Data”

  1. Thanks so touch for this article. I had recent blood work done and noticed a reduced RBC folate and elevated homocysteine. Armed with this information I found your article and looked into the raw data from my 23andMe test I'd had done this spring. Lo and behold, I see I have the MTHFR A1298C mutation GT (one copy of the variant allele). Now, I can consider supplementation to counter this.

  2. Severely decreased activity 677TT, 1298AA. Has anyone sought treatment or supplementation for MTHFR? How did it go? Having trouble finding a doctor that has knowledge and have been self treating with methylfolate.

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