The IL23R gene helps immune cells respond to IL-23, a chemical signal that helps control inflammation and defense against germs. If the gene does not work normally, the immune response may become less balanced and ongoing inflammation can be more likely. In medicine, this gene is important because it helps regulate pathways linked to inflammatory bowel disease, psoriasis, and some forms of arthritis. This gene matters in research and testing, but it has not become widely known through celebrities or major news stories.
What is a gene?
A gene is a stretch of DNA that carries instructions your cells use to make molecules or regulate activities in the body. Some genes provide the directions for producing proteins, which are the working parts of cells. Others are mainly involved in controlling when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can also influence how you respond to food, stress, or medications. For a deeper look at this subject, you can read more in the LearnHub.
Overview
IL23RGene function
What if the gene works
The IL23R gene helps certain immune cells respond to a signal called interleukin 23. This helps your body defend itself while keeping inflammation more balanced, especially in the gut and skin.
Risk
What if the gene does not work
More disruptive variants in the IL23R gene can impair immune defenses and lead to Candida or mycobacterial infections, while milder variants mainly alter risk of inflammatory conditions such as Crohn disease, ulcerative colitis, psoriasis, and ankylosing spondylitis.
Treatment
What does that mean for your treatment
No IL23R-specific treatment or drug choice approach is currently established in clinical guidelines for people with a pathogenic or loss-of-function variant in the IL23R gene. The IL23R gene is being studied as part of the IL-23 immune pathway, which is targeted by approved biologic drugs, but treatment choices are not based on IL23R variant status.
Conditions associated with IL23R
Gene function
What if the gene works
Immune cells need clear messages to respond in a measured way. The IL23R gene helps certain white blood cells detect the immune signal IL-23 and pass that message inward. Understanding IL23R gene function helps explain how the body supports ongoing defense at surfaces like the gut and skin.
IL23R provides part of the docking site that lets certain immune cells recognize IL-23. When IL-23 binds, the cell can start a measured response to that outside signal.
After sensing IL-23, this gene helps pass the signal inward through a built in cell relay system. That signal changes which instructions the cell uses, helping it stay ready for immune work.
IL23R helps sustain a group of T cells that produce messenger proteins for ongoing defense. These cells support responses to microbes, especially at body surfaces that regularly meet the outside world.
This signaling pathway supports immune activity in places like the gut and skin, where the body meets food, germs, and the environment. It helps keep protection active while responses stay organized.
What is a variant?
A genetic variant is a minor difference in the DNA sequence within a gene. These differences are common and help shape normal human diversity, including differences in appearance, metabolism, and the way the body responds to environmental influences. Many do not cause any noticeable effect and are simply part of natural genetic variation. In some situations, though, a variant changes how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the IL23R gene can change the receptor’s shape, stability, or how much of it reaches the cell surface, which alters how strongly cells pass along the IL-23 signal. A key point in how IL23R gene variants affect immune signaling is that some changes only slightly reduce or increase signaling, while more disruptive variants can markedly weaken receptor production or signal transfer. These functional differences may influence inflammatory pathways and, in some people, disease risk.
How variants are linked to conditions
Variants in the IL23R gene are most strongly linked to inflammatory bowel disease, especially Crohn's disease and ulcerative colitis. Studies on IL23R gene variants and Crohn's disease risk show that some changes are associated with higher risk, while others are linked to a lower chance of disease. Variants in the IL23R gene have also been associated with psoriasis and ankylosing spondylitis. These common variants influence risk, not certainty, so carrying one does not mean you will develop a condition.
A variant is not necessarily a diagnosis
Variants are a routine feature of human biology and are widely found across the general population. Most do not directly affect health and simply reflect natural differences among people. For many genes, having a variant associated with a condition points to a possible link rather than a certain diagnosis, particularly when several genes and environmental influences play a role. In some situations, though, one well understood variant in a particular gene is enough to confirm the diagnosis.
Are there things that can increase or change my risk?
Changes in the IL23R gene can shift the chance of some immune-related conditions, especially Crohn’s disease, ulcerative colitis, psoriasis, and some forms of arthritis, but they do not decide your future on their own. Overall risk is also shaped by other genes, family history, and outside factors such as smoking, which is known to raise the risk of Crohn’s disease and can make it worse.
Inheritance of IL23R variants
There is not a broadly confirmed single-gene inheritance pattern tied to a specific IL23R-related condition. In practice, how IL23R gene variants are inherited is usually discussed in the setting of common immune conditions, where IL23R can influence risk but does not by itself determine whether someone will develop a disease. The IL23R gene is located on chromosome 1, which is an autosome, so you inherit one copy from your mother and one copy from your father.
What does my IL23R result mean for my family?
There isn't yet a broadly confirmed, condition-specific family pattern used in routine care for IL23R. Some IL23R changes are linked more to shifting the chance of certain immune-related conditions than to a single inherited condition, so what a result means for relatives depends on the exact change found.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for IL23R variants uses DNA from a saliva sample or blood draw to look for changes in the IL23R gene, usually by sequencing or targeted genotyping. Results can show whether you carry a known variant, but for IL23R they usually add risk information rather than confirming or ruling out a diagnosis.
When should I consider getting a genetic test?
There is not yet a broadly established reason to get genetic testing just for the IL23R gene. Decisions about testing are usually based on your own health and family history and are best made with a doctor or genetic counselor.
A genetic result is only one part of your health story
Genetic findings can be informative, but what they reveal varies with the condition and the kind of variant present. Over time, factors including lifestyle, environment, age, and medical history also influence how the body functions. In some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most useful when considered alongside the rest of a person’s care. In other situations, a genetic result can give a clear answer. In areas like medication response, it can also help place personal experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. A treatment that works well for one person may work less well for another, or may cause more side effects, because the body can absorb, break down, transport, or respond to the drug differently. These inherited differences are common and are one reason medication response can vary even when people take the same dose. Genetics is only one part of the picture, alongside age, kidney and liver function, other medicines, and overall health.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the response to medications. It looks at connections between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes influence how strongly a drug works or how the body handles it. This information can support more informed, more individualized treatment decisions. To explore the subject further, more information is available in the LearnHub.
Drugs influenced by the IL23R gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices, so concerns about treatment response or side effects are best discussed with your doctor. For the IL23R gene, studies have explored whether genetic differences may affect response to some immune-targeting medicines used for conditions like psoriasis or inflammatory bowel disease, but this is not part of routine care.
History
The IL23R gene entered medical genetics in the 2000s, when studies of inflammatory bowel disease found that inherited differences in this gene were linked to Crohn’s disease. This was an important step because it helped shift research toward immune signaling pathways that drive long term inflammation. From these first observations, research expanded steadily. Soon after, IL23R variants were also connected with ulcerative colitis, psoriasis, and ankylosing spondylitis, showing that several immune related conditions share some of the same biology. That discovery helped shape modern research on targeted treatments aimed at the IL-23 pathway, and it remains a key part of how scientists think about immune mediated disease today.