rs165631
A SNP in the COMT gene on chromosome 22. Its most notable genotype is C;T: Perhaps slightly lower risk for breast cancer in BRCA1/2 mutation carriers?
- Gene
- COMT
- Location
- Chr 2219,964,293 (GRCh38)
- Highest magnitude
- 1.0Minor
- Tested on
- 23andMe
Genotypes
As shown in 23andMe and AncestryDNA files.
- C;CGoodcommon/normal
- C;TMost notableGoodPerhaps slightly lower risk for breast cancer in BRCA1/2 mutation carriers?
On SNPedia: (C;C), (C;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Conditions, medicines and genes
Other COMT SNPs
- rs4680A;A(worrier) advantage in memory and attention tasksWorth knowing
- rs4633C;Thigher risk for endometrial cancerWorth knowing
- rs6267G;GcommonTypical
- rs165688G;GNo summary available.Typical
- rs737865C;TNo summary available.Typical
- rs740602G;Gcommon in complete genomicsTypical
- rs769224G;GNo summary available.Typical
- rs8192488C;Ccommon in complete genomicsTypical
Notes
From SNPedia
Show notes, about 150 words
rs165631, also known as p.L203, represents a synonymous variant in the COMT gene; the minor rs165631(T) allele has a population allele frequency of 1% (based on exome sequencing of 60,000 individuals). Admittedly based on only a handful of cases, a preliminary report hunting for variants that might delay or prevent breast cancer in women carrying either disease-causing BRCA1 or BRCA2 mutations observed that the rs165631(T) allele was present in 5 of 15 women with BRCA1/2 mutations (but not breast cancer), while it was not present in any of 25 women with breast cancer (in a different group of women). The authors believe their study "suggests an intriguing genetic correlation", i.e. that rs165631(T) carriers who harbor BRCA1 or BRCA2 mutations might be at lower risk for breast cancer than non-carriers (of this COMT allele).
C;T
see discussion at rs165631; evidence is preliminary
Source and license
Adapted from rs165631 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.