rs1800734
A SNP in the MLH1 gene on chromosome 3. Its most notable genotype is G;G: common in clinvar
- Gene
- MLH1
- Location
- Chr 336,993,455 (GRCh38)
- Highest magnitude
- 0.0Typical
- Tested on
- 23andMe, AncestryDNA, FamilyTreeDNA
- Minor allele frequency
- 31%
Genotypes
As shown in 23andMe and AncestryDNA files.
On SNPedia: (G;G). 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.
- AverageG;G 49%
- European ancestry (Utah)G;G 64%
- Han Chinese (Beijing)G;G 27%
- Japanese (Tokyo)G;G 25%
- Yoruba (Nigeria)G;G 66%
- African ancestry (Southwest US)G;G 67%
- Chinese (Denver)G;G 18%
- Gujarati IndianG;G 41%
- Luhya (Kenya)G;G 76%
- Mexican ancestry (Los Angeles)G;G 45%
- Maasai (Kenya)G;G 67%
- TuscanG;G 48%
Related
Conditions, medicines and genes
Other MLH1 SNPs
- rs11541859G;TLynch syndrome, pathogenic mutationVery important
- rs35001569A;TLynch syndrome, pathogenic mutationVery important
- rs41542214C;TLynch syndromeVery important
- rs63749795C;TLynch syndrome, pathogenic mutationVery important
- rs63749804-;CLynch syndrome, pathogenic mutationVery important
- rs63749813-;GALynch syndrome, pathogenic mutationVery important
- rs63749816-;CLynch syndrome, pathogenic mutationVery important
- rs63749818A;CLynch syndrome, pathogenic mutationVery important
Notes
From SNPedia
Notes
colorectal cancer (-93G>A, rs1800734) 1,518 patients with CRC, homozygosity for the MLH1 -93A variant was associated with a significantly increased 3-fold risk of CRC negative for MLH1 protein by immunohistochemistry (odds ratio (OR): AA vs GG = 3.30, 95% CI 1.46-7.47, n = 1392, p = 0.004, MLH1 negative vs MLH1 positive CRC) and with a 68% excess of proximal CRC (OR: AA vs GG=1.68, 95% confidence interval (CI) 1.00-2.83, n = 1,518, p = 0.05, proximal vs distal CRC)
Source and license
Adapted from rs1800734 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.