rs55770810
A SNP in the BRCA1 gene on chromosome 17. Its most notable genotype is A;G: Likely miscall in Ancestry data; otherwise, BRCA1 variant likely to be pathogenic for breast cancer
- Gene
- BRCA1
- Location
- Chr 1743,063,931 (GRCh38)
- Highest magnitude
- 6.0Very important
- Tested on
- 23andMe, AncestryDNA
Genotypes
Plus strand, as in 23andMe and AncestryDNA files.
- G;GGoodnormal
- A;GMost notableBadLikely miscall in Ancestry data; otherwise, BRCA1 variant likely to be pathogenic for breast cancer
- A;ABadcarrier of two copies of BRCA1 variant; likely to be at higher risk for breast/ovarian cancer
SNPedia records rs55770810 on the minus strand: (C;C), (C;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Conditions, medicines and genes
Other BRCA1 SNPs
- rs28897696T;Tcarrier of two copies of BRCA1 variant; likely to be at high risk for breast/ovarian cancerVery important
- rs41286296A;CBRCA1 pathogenic mutation associated with breast cancerVery important
- rs62625306A;CBRCA1 pathogenic mutation associated with breast cancerVery important
- rs62625307A;GBRCA1 pathogenic mutation associated with breast cancerVery important
- i6051899A;Clikely to be BRCA1 variant pathogenic for breast cancerVery important
- rs1800747C;TBRCA1 pathogenic mutation associated with breast cancerVery important
- rs28897672A;Tconsidered a pathogenic BRCA1 breast cancer variantVery important
- rs28897686A;CBRCA1 pathogenic mutation associated with breast cancerVery important
Notes
From SNPedia
Show notes, about 130 words
rs55770810, also known as c.5095C>T or R1699W, is a SNP in the BRCA1 gene. The more common (C) allele encodes the amino acid arginine (R), while the rare (T) allele encodes a tryptophan (W). An analysis of sequence variants of unknown clinical significance in the BRCA1 and BRCA2 genes concluded that this SNP was among the top 10 (over both genes) likely to lead to breast cancer, with a calculated odds of over 1,000:1 against this just being a spurious association. Although the clinical importance has not been proven, this may still be of use for genetic counseling. This SNP is also represented on some 23andMe microarrays as i5010082.
A;G
see rs55770810 for discussion.
A;A
Listed as pathogenic for breast cancer in ClinVar; see rs55770810 for discussion.
Source and license
Adapted from rs55770810 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.