IL23R rs11209026: What Your Genotype Means
The rs11209026 variant in the IL23R gene is a well-studied genetic change that alters a single amino acid in the interleukin-23 receptor. This specific variation is widely recognized for its protective association against several chronic inflammatory conditions, most notably inflammatory bowel disease (IBD).
What each genotype means
Typical inflammatory bowel risk
This is the most common genotype for this variant. Research indicates that individuals with this genotype do not carry the specific protective genetic change associated with the Arg381Gln mutation, meaning they do not receive the associated reduction in risk for inflammatory bowel disease.
Carried by the vast majority of individuals in most global populations, as the protective A allele is relatively uncommon.
Reduced inflammatory bowel risk
Carrying one copy of the A allele (p.Arg381Gln) is associated with a protective effect against developing inflammatory bowel disease, including Crohn's disease and ulcerative colitis. This variant is thought to result in a loss of function in the IL-23 receptor, which may dampen the inflammatory response.
Carried by roughly 1 in 7 to 1 in 10 people of European ancestry; it is significantly less common or absent in many other global populations.
Strongly reduced bowel risk
Carrying two copies of the A allele (p.Arg381Gln) provides a strong protective association against inflammatory bowel disease compared to those without the variant. This genotype is linked to altered IL-23 signaling, which is a key pathway in the development of chronic mucosal inflammation.
This homozygous genotype is rare, occurring in approximately 0.25% to 0.5% of individuals of European ancestry.
Understanding the Variant
The variant rs11209026 is a single nucleotide polymorphism (SNP) located within the IL23R gene on chromosome 1p31. In genetic terms, this is a missense variant, meaning the change in the DNA sequence results in a different amino acid being incorporated into the protein structure. Specifically, the substitution of a guanine (G) for an adenine (A) at this position leads to the replacement of the amino acid arginine with glutamine at position 381 of the IL-23 receptor protein. This is frequently referred to in scientific literature as p.Arg381Gln or R381Q. Because this change occurs in a functional part of the receptor, it has been the subject of extensive research to determine how it influences the body's immune response and susceptibility to inflammatory conditions.
The Role of the IL23R Gene
The IL23R gene provides instructions for making a protein that forms one part of the interleukin-23 receptor. This receptor is found on the surface of various immune cells, including T cells. When the receptor binds to the cytokine interleukin-23, it triggers a signaling pathway that promotes inflammation and helps the immune system respond to infections. While this process is essential for fighting off pathogens, an overactive or misregulated IL-23 pathway can contribute to chronic inflammation. The R381Q variant is believed to cause a 'loss of function' in this receptor. By dampening the signaling activity of the IL-23 pathway, the variant may reduce the intensity of the immune response, which is thought to be the mechanism behind its protective effect against autoimmune and inflammatory disorders.
Research and Associations
The association between rs11209026 and reduced risk for inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is supported by numerous genome-wide association studies. Research indicates that individuals carrying the minor allele (the A allele) have a significantly lower likelihood of developing these conditions compared to those with the common G allele. Beyond IBD, this variant has also been linked to a decreased risk of other autoimmune conditions, such as psoriasis and ankylosing spondylitis. While the evidence for this protective effect is strong, it is important to note that the association is most consistent in populations of northern European ancestry. In some other populations, the variant may be rare or show different patterns of association, highlighting that genetic risk is complex and influenced by an individual's broader genetic background.
Interpreting Your Results
If you have access to your genetic data, you might see your genotype for rs11209026 listed as GG, GA, or AA. It is important to understand that this information is for educational purposes only and cannot be used to diagnose or predict your personal health outcomes. Genetic variants are only one piece of a much larger puzzle that includes other genes, environmental factors, and lifestyle choices. Having a 'protective' genotype does not guarantee immunity from any disease, nor does having the 'risk' genotype mean you will develop a condition. If you have concerns about your digestive health or family history of inflammatory diseases, the most appropriate step is to consult with a healthcare professional or a genetic counselor. They can provide context based on your full medical history and guide you on appropriate screenings or clinical evaluations.
How common is this variant?
The minor allele (A) of rs11209026 has a frequency of approximately 0.05 to 0.07 in European populations, though its prevalence varies significantly across different global ancestries.
Frequently asked questions
Does having the protective genotype mean I will never get Crohn's disease?
No. While the variant is associated with a lower risk, it does not provide total immunity. Many factors, including other genetic variants and environmental triggers, contribute to the development of Crohn's disease.
Is this variant used for medical diagnosis?
No, this variant is not used as a diagnostic tool. It is a research finding used to understand the biological pathways of inflammation, not to screen for or diagnose clinical conditions.
Should I change my diet based on this genotype?
There is no evidence that this genotype requires specific dietary changes. Always consult with a doctor or a registered dietitian before making significant changes to your diet or health regimen.
Why is the association stronger in some populations than others?
Genetic associations can vary due to differences in population history, the presence of other linked genetic variants, and environmental factors. The protective effect of this SNP is most well-documented in European populations.
Sources & further reading
Educational information only, last refreshed 9/21/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Protective missense variant (p.Arg381Gln) in IL23R associated with decreased risk of Crohn's disease, ulcerative colitis, and ankylosing spondylitis.
Associated with susceptibility to inflammatory bowel disease, including Crohn disease and ulcerative colitis.
Intronic regulatory SNP in IL23R modulating Th17 responses and susceptibility to Crohn's disease.