IL23R Gene: What rs11209026 and rs11465804 Mean

Oct 3

4 min read

The IL23R gene codes for a receptor that helps immune cells respond to interleukin-23, a signaling protein involved in inflammatory responses. Two variants available in GenesUnveiled GeneExplorer—rs11209026 and rs11465804—have been studied in Crohn’s disease and other immune-mediated conditions. They are not interchangeable: rs11209026 changes the receptor’s protein sequence, while rs11465804 is a noncoding marker that may tag nearby IL23R variation [R, R].

Already have a raw DNA file? Explore your IL23R results in GeneExplorer.

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What Does the IL23R Gene Do?

The IL23R gene provides instructions for making part of the interleukin-23 receptor. This receptor is found on immune cells including T cells, natural killer cells, monocytes, and dendritic cells. When interleukin-23 binds to its receptor, it starts signals inside the cell that influence immune activity and inflammation [R].

The IL-23 pathway is involved in normal immune defense as well as inflammatory responses. The pathway’s role in Crohn’s disease and other immune-mediated conditions is one reason researchers have studied genetic differences in IL23R [R].

IL23R rs11209026: The Arg381Gln Variant

rs11209026 is a coding variant in IL23R. It is written as c.1142G>A and changes amino acid 381 of the receptor from arginine to glutamine. This protein change is called Arg381Gln or R381Q [R].

In the forward-strand notation used by GenesUnveiled, the A allele encodes the Q381 form. Research has associated this allele with lower susceptibility to Crohn’s disease and several other inflammatory conditions, including ulcerative colitis, ankylosing spondylitis, and psoriasis. The strength of the association varies by condition and study population; it is not a guarantee of protection [R, R, R].

Functional research offers a possible explanation for the Crohn’s association. In experiments using T cells from healthy donors, the Q381 form was associated with lower IL-23-induced STAT3 signaling and fewer IL-23-responsive T cells. These laboratory findings support a biological effect, but they do not measure a person’s current immune activity or predict their health [R].

rs11209026 Genotypes

GG: No A allele at this position; the common reference genotype.
AG: One copy of the A allele associated with R381Q.
AA: Two copies of the A allele associated with R381Q.

These descriptions apply to rs11209026 only. They do not summarize every variant in IL23R or a person’s overall likelihood of developing Crohn’s disease.

rs11465804: A Noncoding IL23R Marker

Unlike rs11209026, rs11465804 is a noncoding intronic marker. It does not change the amino-acid sequence of the IL-23 receptor. Studies have associated it with inflammatory conditions, including Crohn’s disease and ankylosing spondylitis [R, R].

In the forward-strand notation used by GenesUnveiled, G is the alternate allele for this marker. Population studies have associated G with lower susceptibility to ankylosing spondylitis, although an association observed in a group should not be read as an individual prediction [R].

One important detail is that rs11465804 has been found in substantial linkage disequilibrium with rs11209026. In other words, the two markers were often inherited together in some studied populations. An association at rs11465804 may therefore partly reflect nearby genetic variation rather than an independent functional effect of this marker itself. The degree of linkage can differ between populations [R].

rs11465804 Genotypes

TT: No G allele at this position.
GT: One G allele.
GG: Two G alleles.

The genotype count tells you how many G alleles appear at this marker. It does not show that the receptor is currently more or less active, and it should not be combined with rs11209026 as though the two markers were independent risk factors.

What Can an IL23R DNA Result Tell You?

An IL23R result shows which genotype was read at a supported position in your raw DNA file. It can be used to explore how that genotype compares with variants studied in population genetics and functional research.

It does not measure:

current IL-23 levels;
inflammation in the gut, joints, or skin;
IL23R gene expression in a particular tissue;
the full function of the IL-23 pathway;
whether you have or will develop an autoimmune or inflammatory condition.

Crohn’s disease and other immune-mediated conditions involve many genetic and non-genetic influences. A single IL23R result is only one small part of that picture [R].

Frequently Asked Questions

Is the rs11209026 A allele protective?

The A allele is associated with lower susceptibility to Crohn’s disease in population studies, and functional research supports an effect on IL-23 receptor signaling. “Protective” describes a statistical association; it does not mean that a person cannot develop Crohn’s disease.

What does Arg381Gln mean?

Arg381Gln, also written R381Q, describes the change in the IL-23 receptor protein associated with rs11209026: arginine at position 381 is replaced with glutamine.

Is rs11465804 a functional variant?

rs11465804 is intronic and does not change the receptor’s amino-acid sequence. It has been associated with disease susceptibility in studies and may tag nearby IL23R variation through linkage disequilibrium.

Can IL23R variants diagnose Crohn’s disease or ankylosing spondylitis?

No. These variants are studied as susceptibility markers. A genetic result cannot diagnose or rule out a medical condition.

Do these results measure immune activity?

No. They show inherited DNA variants in the raw file. They do not measure present-day receptor activity, cytokine levels, or inflammation.

Explore IL23R in GeneExplorer

GenesUnveiled GeneExplorer checks supported raw DNA files for rs11209026 and rs11465804 and displays the genotypes found at those positions. You can review the IL23R GeneExplorer page or analyze your DNA for free.