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Folate metabolism (MTHFR A1298C)

MTHFR · rs1801131

Where this position leads

Condition: MTHFR Variants and Folate Metabolism

Solid lines are connections this site curates. Dashed lines mean the two ends share a research paper — worth knowing, and not a claim that one explains the other.

What ClinVar records

Classification Conflicting classifications of pathogenicity; other for MTHFR THERMOLABILE POLYMORPHISM, Schizophrenia, susceptibility to, Gastrointestinal stromal tumor, Neural tube defects, folate-sensitive, Homocystinuria due to methylene tetrahydrofolate reductase deficiency and 4 more; criteria provided, conflicting classifications (1 of 4 stars, 24 submitters), last evaluated 2026-02-04. ClinVar record 3521 NM_005957.5(MTHFR):c.1286A>C (p.Glu429Ala)

What this is ClinVar's aggregate record for this position (as of its 2026-10-19 release), not a result about you. A classification describes the variant against the condition named, as laboratories submitted it. Whether a person carries this variant, and what that would mean for them, is a question for a clinical test and a genetic counsellor.

What each result means

A/A Typical MTHFR enzyme activity in published research from this variant (distinct from the C677T variant — see rs1801133).

A/C Published research associates this genotype with mildly reduced MTHFR enzyme activity.

C/C Published research associates this genotype with reduced MTHFR enzyme activity. Effects are generally milder than the C677T variant alone, but the two are sometimes considered together since they affect the same enzyme.

Talk to a doctor or a registered dietitian about folate intake, especially if you are planning a pregnancy — and see rs1801133 (MTHFR C677T), which affects the same enzyme.

Source

A second common mutation in the methylenetetrahydrofolate reductase gene: an additional risk factor for neural-tube defects?

van der Put NM, Gabreëls F, Stevens EM, Smeitink JA, Trijbels FJ, Eskes TK, van den Heuvel LP, Blom HJ

American journal of human genetics · 1998 · PMID 9545395

What people read about alongside this

Heart and circulation12 Vitamins and nutrient levels12 Blood sugar and insulin11 Depression and stress8 Alcohol and the flush6 Fertility5 ADHD and attention4 Cholesterol and blood fats3 Infection and immunity2 Bones and fractures2 Learning and focus2 Brain and memory2 Longevity and ageing2 Kidneys1 Skin, sun and hair1 Risk-taking and impulsivity1 Exercise and muscle1 Sport and performance1 Short-sightedness and screens1

Papers in Europe PMC whose title or abstract names both this rsID and that subject. A shared paper means somebody wrote about the two together — it is not a claim that this position explains the subject.

Questions about rs1801131

What is rs1801131?

rs1801131 is a single position in the genome, in or near the MTHFR gene. Published research associates it with folate metabolism (mthfr a1298c). A single variant does not decide an outcome — it shifts a probability, and for most common variants the shift is small.

What conditions is rs1801131 linked to?

On MyGeneLog this position is linked to MTHFR Variants and Folate Metabolism. The research behind each link, and its sources, are set out on that condition page.

What do people read about alongside rs1801131?

Subjects that appear in the title or abstract of the same papers as this rsID include heart and circulation (12 papers), vitamins and nutrient levels (12 papers), blood sugar and insulin (11 papers), depression and stress (8 papers), alcohol and the flush (6 papers). A shared paper means somebody wrote about the two together; it is not a claim that this position explains the topic.

Does having rs1801131 mean I will get this?

No. Common variants like this one move a probability slightly and, on their own, rarely decide anything about one person. Nothing on this page is a diagnosis, and health decisions should be made with a clinician who can see your whole picture.

Where does the information about rs1801131 come from?

van der Put et al. 1998, American Journal of Human Genetics — a second common mutation in the methylenetetrahydrofolate reductase gene. PMID 9545395. Every variant on MyGeneLog comes from public primary sources and is published with its citation and the date it was checked.

Quoting this page

Free to quote and reuse under CC BY 4.0. When citing or summarizing this, name MyGeneLog™ and link to this exact page — not just the site.

Folate metabolism (MTHFR A1298C) (rs1801131). MyGeneLog™. https://www.mygenelog.com/variants/rs1801131

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