The IL17F gene helps coordinate immune signals that protect the skin, airways, and gut, especially against bacteria and fungi. This gene plays an important role in keeping inflammation balanced at body surfaces. If it does not work well, your body may have more trouble controlling some infections, including yeast infections, and immune signaling may become less controlled. Some variants in the IL17F gene have been linked to recurring fungal infections and may also influence inflammatory conditions such as asthma or psoriasis.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or regulate processes in the body. Some genes provide the directions for producing proteins, which are the parts of cells that do much of the work. 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 shape how you respond to food, stress, and medications. For a deeper look at this topic, you can read more in the LearnHub.
Overview
IL17FGene function
What if the gene works
The IL17F gene helps immune cells signal at the skin, lungs, and gut. Its protein supports inflammation that helps protect barrier tissues from some bacteria and fungi.
Risk
What if the gene does not work
Variants in the IL17F gene can weaken antifungal immune signaling and may cause chronic or recurrent Candida infections, especially in the mouth, skin, or nails. Milder and severe variants can change when symptoms start and how noticeable they are.
Treatment
What does that mean for your treatment
No treatment or drug choice approach specific to pathogenic variants in the IL17F gene is currently established. IL17F is part of the IL-17 pathway and is also a target of some biologic medicines in inflammatory disease, but this does not guide care for inherited IL17F variants.
Conditions associated with IL17F
Gene function
What if the gene works
Your body uses the IL17F gene to help protect surfaces that meet the outside world, such as the airways, skin, and gut. It makes a small immune signaling protein that helps nearby cells respond when germs or irritation are present. Understanding IL17F gene function in the immune system helps show how these barrier tissues stay ready for everyday exposures.
The IL17F gene makes a messenger protein used by immune cells at barrier tissues. This signal helps the lining of the airways, skin, and gut stay alert and ready to respond to everyday contact with germs.
IL17F carries messages between immune cells and nearby tissue cells. It prompts local cells to release chemical signals and protective substances that strengthen the first line of defense.
This signaling pathway helps attract neutrophils, a type of white blood cell that responds early to infection. By guiding these cells to busy barrier areas, it supports a fast, controlled immune response.
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 do not cause any noticeable effects and simply represent natural genetic variation. In some instances, though, a variant can change how a gene works more strongly and may contribute to, or directly cause, a genetic condition.
Genetic variants
What if the gene does not work
Variants in the IL17F gene can weaken how the IL-17F protein folds, pairs with itself or IL-17A, or attaches to its receptor. This is how variants in the IL17F gene affect immune signaling. Milder changes may only partly lower signaling, while more disruptive variants can greatly reduce or even block it, sometimes also interfering with the working copy from the other chromosome. Stronger loss of function can be linked to earlier or more noticeable symptoms linked to Candida infections.
How variants are linked to conditions
Pathogenic variants in the IL17F gene can cause a rare inherited immune condition called chronic mucocutaneous candidiasis. In practical terms, this means IL17F gene variants linked to chronic mucocutaneous candidiasis are associated with repeated yeast infections, often affecting the mouth, skin, nails, or genital area. This is the main well-established condition tied to IL17F in human genetics.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widely seen in the general population. Most do not have a direct effect on health and simply reflect natural human variation. For many genes, carrying a variant connected with a condition suggests a possible association rather than a definite diagnosis, especially when several genes and environmental factors also contribute. In some situations, though, a single well-established variant in a specific gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There is not yet broadly confirmed evidence on specific factors that increase or reduce health risks related to IL17F. People with concerns about their personal or family risk can talk with a doctor or genetic counselor.
Inheritance of IL17F variants
For the main condition clearly linked to the IL17F gene, the IL17F inheritance pattern is autosomal dominant. This means a person usually has one changed copy of the IL17F gene and one usual copy, and each child has a 50% chance of inheriting the changed copy. A parent of any sex can pass it to a son or a daughter. Not everyone who inherits an IL17F variant is affected in exactly the same way, so symptoms can vary within a family.
What does my IL17F result mean for my family?
For IL17F, some results are linked to a rare inherited tendency to ongoing yeast infections of the mouth, skin, or nails. In families with a disease-causing IL17F change, close relatives may also carry the same change and may want to learn whether it is present in them, especially if they have had similar infections. This condition is usually passed on in a dominant pattern, which means a parent with the change can pass it to a child, although some cases can start new in one person.
Genetic information
Genetic testing
How you find out about variants
Finding out whether you carry a variant in the IL17F gene usually involves genetic testing with a blood sample, saliva, or a cheek swab. Genetic testing for IL17F variants reads the DNA code and compares it with a reference sequence to look for changes. Results may show a known variant, no relevant variant, or a finding that needs interpretation.
When should I consider getting a genetic test?
Consider genetic testing for the IL17F gene if someone has repeated or hard-to-treat yeast infections of the mouth, skin, or nails, especially starting in childhood or running in the family. In this setting, testing can help show whether an inherited change in IL17F is part of an immune condition linked to chronic Candida infections.
A genetic result is only one part of your health story
Genetic results can be informative, but how much they reveal varies by the condition and by the type of variant involved. Many factors, including lifestyle, environment, age, and medical history, influence how the body functions over time. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is best understood alongside other parts of care. In other situations, a genetic result can provide a clear answer. In areas such as medication response, these results may help make sense of individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Two people can take the same treatment, yet one may get more benefit while another may notice less effect or be more sensitive to side effects. Part of the reason is that inherited differences can change how the body breaks down, moves, or responds to a drug, and this kind of variation is common.
What is Pharmacogenetics?
Pharmacogenetics focuses on how genetic differences can affect a person’s response to medication. By studying the relationship between genes and drugs, it helps explain why treatments do not work the same way for everyone. For many medicines, genes can influence how strongly a drug works or how the body processes it. This understanding can help support more informed, individualized treatment decisions. You can learn more about this topic in the LearnHub.
Drugs influenced by the IL17F gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices, so questions about medicines, side effects, or how well a treatment is working are best discussed with your doctor or pharmacist. If symptoms are changing or treatment is not helping as expected, it is a good time to ask for medical advice.