rs1736557
A SNP in the FMO3 gene on chromosome 1. Its most notable genotype is A;A: normal?
- Gene
- FMO3
- Location
- Chr 1171,110,939 (GRCh38)
- Highest magnitude
- 1.1Minor
- Tested on
- 23andMe, AncestryDNA, FamilyTreeDNA
- Minor allele frequency
- 9%
Genotypes
As shown in 23andMe and AncestryDNA files.
- A;AMost notableNot ratednormal?
- A;GNot ratedunlikely to be associated with trimethylaminuria unless as a carrier (if that)
- G;GGoodcommon in clinvar
On SNPedia: (A;A), (A;G), (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.
- AverageA;A 1% A;G 16% G;G 82%
- European ancestry (Utah)A;A 0% A;G 14% G;G 86%
- Han Chinese (Beijing)A;A 7% A;G 36% G;G 57%
- Japanese (Tokyo)A;A 2% A;G 25% G;G 74%
- Yoruba (Nigeria)A;A 0% A;G 4% G;G 96%
- African ancestry (Southwest US)A;A 0% A;G 7% G;G 93%
- Chinese (Denver)A;A 3% A;G 39% G;G 58%
- Gujarati IndianA;A 2% A;G 16% G;G 82%
- Luhya (Kenya)A;A 0% A;G 6% G;G 95%
- Mexican ancestry (Los Angeles)A;A 0% A;G 12% G;G 88%
- Maasai (Kenya)A;A 0% A;G 10% G;G 90%
- TuscanA;A 0% A;G 12% G;G 88%
Related
Conditions, medicines and genes
Other FMO3 SNPs
- rs61753344T;Ttrimethylaminuria & possible related issuesImportant
- rs72549320A;Atrimethylaminuria & possible related issues; see discussionWorth knowing
- rs72549321A;Atrimethylaminuria & possible related issues; see discussionWorth knowing
- rs72549322G;Gtrimethylaminuria & possible related issues; see discussionWorth knowing
- rs72549323C;Cpossible trimethylaminuria; see discussionWorth knowing
- rs72549326T;Ttrimethylaminuria & possible related issues; see discussionWorth knowing
- rs72549330T;Ttrimethylaminuria & related issues; see discussionWorth knowing
- rs72549331T;Ttrimethylaminuria & related issues; see discussionWorth knowing
Notes
From SNPedia
Notes
rs1736557, also known as Val257Met, is a SNP in the FMO3 gene. It has been linked to trimethylaminuria; see variant .0002, OMIM 136132.
A;A
This missense homozgous genotype has been reported to be associated with trimethylaminuria, yet other reports indicate it may be a benign polymorphism. One SNPedia self reports this genotype, with no symptoms. Feel free to share your findings/beliefs with SNPedia if you have this genotype.
Source and license
Adapted from rs1736557 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.