rs11805303

A SNP in the IL23R gene on chromosome 1. Its most notable genotype is C;C: normal

Gene
IL23R
Location
Chr 167,209,833 (GRCh38)
Highest magnitude
0.0Typical
Tested on
23andMe, AncestryDNA
Minor allele frequency
33%

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. C;CMost notableGoodnormalTypical · 0.039% of people
  2. C;TBad1.4x risk of Crohn's diseaseTypical · 0.047% of people
  3. T;TBad1.8x risk of Crohn's diseaseTypical · 0.015% of people

On SNPedia: (C;C), (C;T), (T;T). 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.

  • AverageC;C 39% C;T 47% T;T 15%
  • European ancestry (Utah)C;C 51% C;T 39% T;T 10%
  • Han Chinese (Beijing)C;C 23% C;T 53% T;T 25%
  • Japanese (Tokyo)C;C 17% C;T 53% T;T 30%
  • Yoruba (Nigeria)C;C 43% C;T 47% T;T 10%
  • African ancestry (Southwest US)C;C 49% C;T 49% T;T 2%
  • Chinese (Denver)C;C 17% C;T 55% T;T 28%
  • Gujarati IndianC;C 18% C;T 50% T;T 32%
  • Luhya (Kenya)C;C 56% C;T 36% T;T 8%
  • Mexican ancestry (Los Angeles)C;C 66% C;T 33% T;T 2%
  • Maasai (Kenya)C;C 47% C;T 44% T;T 8%
  • TuscanC;C 38% C;T 55% T;T 8%

Conditions, medicines and genes

Other IL23R SNPs

All IL23R SNPs

Notes

From SNPedia

Notes

rs11805303 has been reported in a large study to be associated with Crohn's disease. The risk allele (oriented to the dbSNP entry) is (T); the odds ratio associated with heterozygotes is 1.39 (CI 1.22-1.58), and for homozygotes, 1.86 (CI 1.54-2.24).

Source and license

Adapted from rs11805303 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.