rs1801131
A SNP in the MTHFR gene on chromosome 1. Its most notable genotype is G;G: Number of risks. Complex.
- Gene
- MTHFR
- Location
- Chr 111,794,419 (GRCh38)
- Highest magnitude
- 2.5Worth knowing
- Tested on
- 23andMe, AncestryDNA, FamilyTreeDNA
- Minor allele frequency
- 23%
Genotypes
Plus strand, as in 23andMe and AncestryDNA files.
- T;TGoodmost common genotype
- G;TBadPossibly impaired folate metabolism
- G;GMost notableBadNumber of risks. Complex.
SNPedia records rs1801131 on the minus strand: (A;A), (A;C), (C;C). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Frequency
Share of each genotype in 11 HapMap populations.
- AverageT;T 60% G;T 34% G;G 7%
- European ancestry (Utah)T;T 43% G;T 45% G;G 12%
- Han Chinese (Beijing)T;T 64% G;T 34% G;G 2%
- Japanese (Tokyo)T;T 65% G;T 34% G;G 2%
- Yoruba (Nigeria)T;T 76% G;T 23% G;G <1%
- African ancestry (Southwest US)T;T 65% G;T 33% G;G 2%
- Chinese (Denver)T;T 65% G;T 28% G;G 7%
- Gujarati IndianT;T 39% G;T 46% G;G 16%
- Luhya (Kenya)T;T 68% G;T 27% G;G 5%
- Mexican ancestry (Los Angeles)T;T 64% G;T 31% G;G 5%
- Maasai (Kenya)T;T 56% G;T 35% G;G 8%
- TuscanT;T 51% G;T 36% G;G 13%
Related
Conditions, medicines and genes
Other MTHFR SNPs
- rs1801133A;Ahomozygous for C677T of MTHFR = 10-20% efficiency in processing folic acid = high homocysteine, low B12 and folate levelsWorth knowing
- rs17367504G;Greduction in blood pressureMinor
- rs1476413C;Ccommon/normalTypical
- rs1537514G;Gcommon in clinvarTypical
- rs2066462G;Gcommon in clinvarTypical
- rs2066470G;Gcommon in clinvarTypical
- rs2274976C;Ccommon in complete genomicsTypical
- rs4846048G;Gcommon in clinvarTypical
Genosets
- Gs193Effects due to MTHFR polymorphisms affecting homocysteine?Important
- Gs231Rare genotype which may not respond to multivitamins.Important
- Gs192MTHFR polymorphisms affecting homocysteineWorth knowing
Genosets combine several genotypes. Twofold checks them in your report.
Notes
From SNPedia
Show notes, about 240 words
rs1801131 is a SNP in the MTHFR gene, representing an A>C mutation at mRNA position 1298, resulting in a glu429-to-ala (E429A) substitution (hence this SNP is also known as A1298C or E429A). A diplotype (according to the authors, but perhaps actually a genoset) of rs1801131 and rs1801133 has been linked to slightly increased risk for several types of brain cancer. The highest risk of meningioma was associated with heterozygosity for both MTHFR SNPs (odds ratio 2.11, CI: 1.42-3.12, p=0.002). The corresponding odds ratio for glioma was 1.23 (CI: 0.91-1.66, p=0.02. In general, risks were increased with genotypes associated with reduced MTHFR activity. rs1801131 shows no consistent association with schizophrenia overall in 12 studies totaling 3,000+ patients
G;T
MTHFR rs1801131 (C) or MTHFR A1298C is a mutation in the folate pathway, specifically in the enzyme involved in converting 5-methylfolate (5MTHF) to tetrahydrofolate (THF). Defects in folate metabolism can increase the risk of neural tube defects and possibly contribute to risk of stroke / heart attack. Unlike rs1801133 or MTHFR C677T, this mutation does not lead to elevated homocysteine levels, however some studies have suggested that there may be a synergistic effect in individuals heterozygous for both mutations.
G;G
MTHFR rs1801131 is involved in converting 5-methylfolate (5MTHF) to tetrahydrofolate (THF). Unlike MTHFR C677T, this mutation does not lead to elevated homocysteine levels.
References
Source and license
Adapted from rs1801131 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.
SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.