DNA Methylation Genes: What Raw DNA Can Show

DNA methylation genes are genes that help create, use, or respond to methyl groups in pathways such as folate metabolism, methionine recycling, homocysteine handling, and catecholamine breakdown. A consumer raw DNA file can sometimes show inherited variants in genes such as MTHFR, MTRR, MTR, COMT, CBS, BHMT, AHCY, and PEMT. A raw DNA file does not measure your current DNA methylation levels, epigenetic age, homocysteine, folate, or B12 status.

That distinction matters because two different things often get called "methylation testing":

Why the word methylation gets confusing

DNA methylation is an epigenetic process. The CDC explains epigenetic changes as changes that affect how the body reads DNA without changing the DNA sequence itself. DNA methylation is one example: a methyl group is added to DNA, and that chemical tag can influence whether a gene is more or less active in a specific cell context.

The NHGRI glossary entry for methylation puts the same idea more simply: methylation in DNA can alter gene expression. A detailed review in Neuropsychopharmacology describes DNA methylation as a regulated process involving DNA methyltransferases and methylated cytosines, with effects that vary by genomic context and cell type (Moore, Le and Fan, 2013).

Consumer raw DNA files are different. A 23andMe, AncestryDNA, or MyHeritage raw file usually reports genotype calls at selected inherited markers. It may show something like rs1801133 C/T for MTHFR C677T or rs4680 A/G for COMT Val158Met. Those rows are DNA sequence variants, not methyl tags measured on DNA.

Methylation-related genes people often look up

The useful way to read a raw file is pathway by pathway, not one variant at a time. A single marker can be interesting, but methylation biology depends on folate status, B12, B6, choline, kidney function, medications, pregnancy status, diet, alcohol intake, inflammation, and many other non-genetic factors.

Commonly discussed genes include:

The most familiar example is MTHFR C677T, also known as rs1801133. NCBI lists MTHFR as Gene ID 4524, and the NIH Genetic Testing Registry describes rs1801133 as a common C677T polymorphism in that gene. It is worth understanding, but it is not a diagnosis. Someone with a reduced-activity MTHFR genotype may still have normal homocysteine and adequate folate status. Someone without the common MTHFR variants can still have nutrition, medication, kidney, thyroid, pregnancy, alcohol, or inflammatory reasons for abnormal labs.

COMT is another common example. NCBI lists COMT as Gene ID 1312, and consumer methylation reports often discuss COMT because catechol-O-methyltransferase uses methyl groups while metabolizing catechol compounds. That makes COMT relevant context, but it does not make a raw DNA result a mood diagnosis or supplement instruction.

What a raw DNA file can do well

A raw DNA file is useful for identifying inherited markers that should be interpreted cautiously. It can help answer questions such as:

• Does my file include common methylation-pathway markers like MTHFR C677T or COMT Val158Met?
• Are the variants being discussed actually present in my file, or did a tool infer them from a partial dataset?
• Which report area should I review first: folate and B vitamins, detox and methylation context, mental wellbeing, or medication-response research?
• Which findings are worth summarizing for a clinician because they intersect with symptoms, medications, family history, or abnormal labs?

That is the GenoSight use case. GenoSight reads a compatible raw file, extracts selected pathway-relevant variants, and frames them inside educational reports with citations and caveats. The Detox and Methylation report is meant to organize context around genes such as MTHFR, COMT, MTR, MTRR, CBS, and related pathways. It does not measure methylation levels, diagnose a methylation disorder, or prescribe supplements.

For file handling basics, start with how to download raw DNA data. For the broader privacy model, read raw DNA data privacy after upload. For source discipline, see where GenoSight insights come from.

What a raw DNA file cannot prove

Raw DNA interpretation gets risky when a variant is treated as a lab result. A consumer genotype file generally cannot tell you:

• whether your DNA is currently over-methylated or under-methylated;
• your homocysteine, folate, B12, B6, methylmalonic acid, or choline status;
• whether you should start, stop, or dose a supplement;
• whether symptoms such as fatigue, anxiety, insomnia, miscarriage, neuropathy, or brain fog are caused by a methylation gene;
• whether a medication, pregnancy plan, or medical treatment should change.

Those questions require clinical context. Depending on the situation, a clinician may consider blood chemistry, medical history, medications, diet, pregnancy status, kidney function, family history, or a purpose-built clinical test. Raw DNA can help you ask a better question. It should not become the answer by itself.

How to read methylation gene results safely

Use a four-step review:

1. Confirm the marker. Start with the exact rsID and genotype from an untouched raw file. Do not rely on a screenshot or a re-saved spreadsheet if the original export is available.
2. Separate inherited variant from current state. Write down whether you are looking at genotype, epigenetic methylation, or blood chemistry. Mixing these categories is the main source of bad advice.
3. Check the pathway and the evidence. MTHFR, MTRR, MTR, COMT, CBS, BHMT, AHCY, and PEMT belong to related but different roles. A variant in one gene should not be turned into a whole-cycle conclusion.
4. Bring clinical questions to a professional. If the issue involves pregnancy, medication response, abnormal labs, neurological symptoms, clotting history, depression, or persistent fatigue, use the raw DNA result as discussion context rather than a treatment plan.

The practical takeaway

DNA methylation genes can be useful to review when you already have a raw DNA file, especially if you want organized context around folate, B vitamins, COMT, homocysteine pathways, and related report areas. The safe interpretation is narrow: inherited variants are clues, not measurements of your current methylation state.

If your goal is learning, a raw DNA report can help. If your goal is diagnosing a symptom, changing medication, planning pregnancy care, or choosing supplements, pair the genotype context with current labs and qualified clinical guidance.

Sources

• CDC - Epigenetics, Health, and Disease, accessed October 2, 2026.
• NHGRI - Methylation, accessed October 2, 2026.
• Moore LD, Le T, Fan G. DNA methylation and its basic function. Neuropsychopharmacology. 2013.
• NCBI Gene - MTHFR methylenetetrahydrofolate reductase, accessed October 2, 2026.
• NCBI Gene - COMT catechol-O-methyltransferase, accessed October 2, 2026.
• NIH Genetic Testing Registry - MTHFR thermolabile polymorphism, accessed October 2, 2026.
• GenoSight - How to download raw DNA data.
• GenoSight - Raw DNA data privacy after upload.