The IL18BP gene helps your body make a protein that soaks up IL-18, an immune signal, so inflammation stays under control. If this gene does not work, immune cells may become overactive and release too much inflammation, which can damage tissues. Rare severe variants have been linked to sudden liver inflammation during infections such as hepatitis A.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or regulate activities in the body. Some genes hold the information needed to produce proteins, the parts of cells that do the work. Other genes mainly help direct when certain processes happen, where they happen, and how active they are. Together, genes affect how the body develops and works, and they can influence how you respond to food, stress, or medications. For a deeper look at this topic, you can learn more in the LearnHub.
Overview
IL18BPGene function
What if the gene works
The IL18BP gene helps make a protein that binds IL-18, an immune signal. This helps keep inflammation under control and can limit tissue damage during infections and other immune responses.
Risk
What if the gene does not work
More severe variants in the IL18BP gene can leave IL-18 activity less controlled, leading to extreme inflammation. In the best-known cases, this is linked to fulminant viral hepatitis, especially hepatitis A, while milder variants may have smaller effects.
Treatment
What does that mean for your treatment
No treatment or drug choice based specifically on a pathogenic variant in the IL18BP gene is currently established. The IL18BP gene is an active research target, and recombinant IL 18BP, including tadekinig alfa, is being studied for IL 18 driven inflammation.
Gene function
What if the gene works
In everyday immune defense, your body needs some signals to turn inflammation on and others to keep it from running too high. The IL18BP gene helps provide that balance by making a protein that captures interleukin-18, an immune messenger. This is part of how the IL18BP gene helps control inflammation in the body.
The IL18BP gene makes a protein that is released outside cells and binds tightly to interleukin-18, an immune messenger. By holding onto this signal, it keeps the message from spreading freely through nearby tissues.
When interleukin-18 is already bound by the IL18BP protein, it cannot easily attach to its usual cell receptor. This helps limit one of the body’s main pathways for raising inflammatory activity.
Through this natural buffering system, the IL18BP gene helps fine tune immune responses rather than letting them build unchecked. It supports a more measured release of downstream signals such as interferon gamma, another immune signal.
What is a variant?
A genetic variant is a minor difference in the DNA sequence within a gene. These differences are common and are part of normal human diversity, including variation in appearance, metabolism, and the way the body reacts to environmental influences. Many have no noticeable effect and simply represent natural genetic variation. At times, though, a variant can change how a gene functions more substantially and may contribute to, or cause, a genetic condition.
Genetic variants
What if the gene does not work
Variants in the IL18BP gene can reduce how much IL-18 binding protein is made, whether it is released from the cell, and how well it attaches to IL-18. This explains how IL18BP gene variants affect protein function: milder changes may partly weaken stability or binding, while more severe loss of function variants can leave little or no working protein. Complete IL18BP deficiency can then drive excess IL-18 signaling and very severe inflammation during hepatitis A infection.
How variants are linked to conditions
Rare, severe variants in the IL18BP gene are linked to inherited susceptibility to fulminant viral hepatitis, especially life threatening hepatitis A in childhood. When a person inherits disease causing IL18BP variants from both parents, this can cause IL18BP deficiency and help confirm the diagnosis. Outside this rare condition, common IL18BP variants are not used to diagnose more common liver or inflammatory diseases.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are widespread in the general population. Most do not directly affect health and instead reflect normal human variation. For many genes, having a variant associated with a condition indicates a possible link rather than a definite diagnosis, especially when several genes and environmental factors contribute. In some situations, though, one well understood variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There isn't yet broadly confirmed evidence on specific factors that increase or reduce risk related to the IL18BP gene. If a change in IL18BP is found, risk and health effects can depend mainly on the exact genetic change and a person's overall immune health, so personal guidance from a doctor or genetic counselor is important.
Inheritance of IL18BP variants
IL18BP-related conditions are inherited in an autosomal recessive pattern. This means a person usually inherits one IL18BP gene variant from each parent, and both copies need to carry a disease-causing change for the condition to develop. Parents who each carry one variant are often unaffected carriers. With autosomal recessive inheritance of IL18BP gene variants, each pregnancy has a 25% chance of an affected child, a 50% chance of a child who is a carrier, and a 25% chance of a child with neither variant.
What does my IL18BP result mean for my family?
For families with a disease-causing IL18BP result, this condition is passed down in a recessive way, so close relatives may also carry the changed gene without having symptoms. Brothers and sisters could be affected if they inherited the same change from both parents, while parents are usually healthy carriers. Other blood relatives may also be carriers, especially on the same side of the family.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the IL18BP gene, genetic testing for IL18BP variants examines DNA from blood, saliva, or a cheek swab. The lab reads the gene's code and looks for variants that may help explain an immune condition or clarify whether a change runs in a family.
When should I consider getting a genetic test?
There isn't yet a broadly established reason to test the IL18BP gene in routine care. Testing may be considered with a doctor or genetic counselor if someone has a very unusual history of severe liver inflammation, especially after hepatitis A, or a family history suggesting a rare inherited immune condition.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it explains varies based on the condition and the type of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body works. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is best understood together with other parts of care. In other situations, a genetic result may offer a clear answer. In areas such as medication response, genetic results can also help put individual experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can influence how your body responds to medicines. Small differences in DNA can affect how a drug is absorbed, broken down, moved through the body, or how strongly the body reacts to it. That helps explain why the same treatment may work well for one person, work less well for another, or cause more side effects in some people.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes can affect their response to medicines. By studying links between genes and medications, it helps explain why the same treatment may not work the same way for everyone. For many drugs, genes can influence both how strongly a medicine works and how the body handles it. Understanding this can support treatment choices that are more informed and more tailored to the individual. More detailed information on this topic is available in the LearnHub.
Drugs influenced by the IL18BP gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choice or dose, so questions about side effects, how well a treatment is working, or other health concerns are best discussed with your doctor.