rs1801270

A SNP in the CDKN1A gene on chromosome 6. Its most notable genotype is A;A: increased risk for lung cancer

Gene
CDKN1A
Location
Chr 636,684,194 (GRCh38)
Highest magnitude
0.0Typical
Tested on
23andMe, AncestryDNA, FamilyTreeDNA
Minor allele frequency
25%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AMost notableBadincreased risk for lung cancerTypical · 0.010% of people
  2. A;CBadincreased risk for lung cancerTypical · 0.036% of people
  3. C;CGoodnormal riskTypical · 0.054% of people

On SNPedia: (A;A), (A;C), (C;C). 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 10% A;C 36% C;C 54%
  • European ancestry (Utah)A;A 0% A;C 8% C;C 92%
  • Han Chinese (Beijing)A;A 26% A;C 39% C;C 36%
  • Japanese (Tokyo)A;A 17% A;C 46% C;C 37%
  • Yoruba (Nigeria)A;A 8% A;C 46% C;C 46%
  • African ancestry (Southwest US)A;A 4% A;C 47% C;C 49%
  • Chinese (Denver)A;A 26% A;C 55% C;C 19%
  • Gujarati IndianA;A 4% A;C 30% C;C 66%
  • Luhya (Kenya)A;A 14% A;C 35% C;C 51%
  • Mexican ancestry (Los Angeles)A;A 7% A;C 40% C;C 53%
  • Maasai (Kenya)A;A 6% A;C 38% C;C 56%
  • TuscanA;A 2% A;C 15% C;C 83%

Conditions, medicines and genes

Notes

From SNPedia

Notes

rs1801270 is a SNP known as p21 codon 31, although the gene now known to code for the p21 protein is termed CDKN1A, and has also been known as WAF1 and CIP1. Along with p53 codon 72 (rs1042522), it is one of the best studied SNPs due to its role in increased tumor susceptibility (and thus cancer). A study of ~150 lung cancer patients in Sweden found that the rs1801279(A) allele, encoding the amino acid Arg at codon 31, represented the risk allele (odds ratio 1.7, CI: 1.0-2.9), compared to healthy individuals. The difference was even more striking when compared to patients with chronic obstructive pulmonary disease (COPD), in which case the odds ratio was over 5.

Source and license

Adapted from rs1801270 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.