rs7158782

A SNP in the TCL1A gene on chromosome 14. Its most notable genotype is G;G: 4x higher risk of adverse side-effect if taking aromatase inhibitor

Gene
TCL1A
Location
Chr 1495,702,794 (GRCh38)
Highest magnitude
4.0Very important
Tested on
23andMe, AncestryDNA
Minor allele frequency
33%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AGoodnormalTypical · 0.046% of people
  2. A;GBad2x higher risk of adverse side-effect if taking aromatase inhibitorWorth knowing · 2.033% of people
  3. G;GMost notableBad4x higher risk of adverse side-effect if taking aromatase inhibitorVery important · 4.022% of people

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 46% A;G 33% G;G 22%
  • European ancestry (Utah)A;A 74% A;G 26% G;G <1%
  • Han Chinese (Beijing)A;A 69% A;G 28% G;G 4%
  • Japanese (Tokyo)A;A 63% A;G 38% G;G 0%
  • Yoruba (Nigeria)A;A 3% A;G 27% G;G 71%
  • African ancestry (Southwest US)A;A 5% A;G 49% G;G 46%
  • Chinese (Denver)A;A 61% A;G 36% G;G 4%
  • Gujarati IndianA;A 76% A;G 22% G;G 2%
  • Luhya (Kenya)A;A 6% A;G 35% G;G 59%
  • Mexican ancestry (Los Angeles)A;A 64% A;G 33% G;G 3%
  • Maasai (Kenya)A;A 11% A;G 42% G;G 47%
  • TuscanA;A 71% A;G 27% G;G 3%

Conditions, medicines and genes

Notes

From SNPedia

Show notes, about 160 words

rs7158782 is one of 4 SNPs found on chromosome 14 near a gene known as T-cell leukemia/lymphoma 1A (TCL1A). This gene appears to be estrogen dependent. In a study of ~300 patients with early-stage estrogen receptor&#8211;positive (ER+) breast cancer who were treated with the aromatase inhibitor (AI) anastrozole or exemestane and who developed musculoskeletal toxicity severe enough to prompt discontinuation, rs7158782(G) allele carriers were at ~2x higher risk for toxicity (CI: 1.5 - 2.9, p < 10e-6). The population attributable risk (i.e., the fraction of such adverse events that could be due to this allele) was estimated to be 11%. An editorial accompanying this article downplays the clinical utility of this finding, since testing for this allele, given its frequency and (mere) doubling of risk, has about equal odds of yielding a true positive and a false positive.

A;G

2x higher risk of adverse side-effect if taking aromatase inhibitor

Source and license

Adapted from rs7158782 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.