The FLCN gene helps control how cells grow, use energy, and respond to changes in their environment. The protein made by this gene acts like a brake in certain tissues, especially the skin, lungs, and kidneys. If you carry a harmful variant that stops it working properly, you may develop Birt-Hogg-Dubé syndrome, which can cause small skin growths, lung cysts with a collapsed lung, and a higher chance of kidney tumors. Many variants in this gene have little effect, while a few clearly disrupt its job.
What is a gene?
Genes are stretches of DNA that give your cells instructions for making molecules or guiding activity in the body. Some genes carry the directions to produce proteins, which do much of the cell’s work. Others mainly regulate when specific processes happen, where they happen, and how active they are. Taken together, genes affect how your body grows and works, and they can shape how you respond to food, stress, or medications. For a deeper look at this subject, you can find more information in the LearnHub.
Overview
FLCNGene function
What if the gene works
The FLCN gene helps cells sense nutrient levels and manage growth. It supports energy balance and cell recycling, especially in the kidneys, lungs, and skin.
Risk
What if the gene does not work
Variants in the FLCN gene can cause Birt-Hogg-Dubé syndrome, linked to skin bumps, lung cysts with collapsed lungs, and kidney tumors. Milder or more severe variants can influence which features appear, when they start, and how strongly they affect a person.
Treatment
What does that mean for your treatment
No FLCN-specific drug treatment or management approach is currently established. Care usually relies on standard measures for the problems that arise, such as kidney-sparing surgery for kidney tumors and usual treatment for collapsed lungs. The FLCN gene is being studied as a marker and pathway target in kidney cancer research, but this has not yet changed routine care.
Conditions associated with FLCN
Gene function
What if the gene works
In everyday cell life, the FLCN gene helps cells judge when to grow, when to conserve energy, and when to recycle worn out parts. Its protein, folliculin, acts like a coordinator rather than a simple switch. Understanding what the FLCN gene does in cells helps explain how tissues keep a steady balance over time.
The FLCN gene helps cells read nutrient signals, especially at the lysosome (a cell compartment that breaks down and reuses materials). This helps match cell growth to the resources available.
Through mTOR signaling (a major growth control pathway), the FLCN gene helps cells decide when conditions are right for building and growth. This keeps everyday cell activity aligned with nutrient and energy supply.
Folliculin works with energy sensing pathways that tell cells when fuel is low. This supports a measured shift between using energy, storing it, and making new cell parts.
At the lysosome, folliculin helps coordinate normal cleanup and reuse of cell materials. This supports autophagy (the cell's recycling process), which helps cells maintain balance over time.
What is a variant?
A genetic variant is a minor alteration in the DNA sequence within a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, and the way the body reacts to environmental influences. Many variants do not cause any noticeable effects and are simply part of natural genetic variation. At times, though, a variant can change how a gene works more significantly and may contribute to or lead to a genetic condition.
Genetic variants
What if the gene does not work
Many variants in the FLCN gene create a shortened or unstable folliculin protein that breaks down early or cannot bind partner proteins, altering growth signals in cells. This shows how variants in the FLCN gene affect the folliculin protein in Birt-Hogg-Dubé syndrome. Some variants leave partial activity, while more severe variants cause almost complete loss of function, meaning very little working protein is left. That can shape when features appear and how strongly the kidneys, lungs, or skin are involved.
How variants are linked to conditions
Pathogenic variants in the FLCN gene cause Birt-Hogg-Dubé syndrome, a condition linked to lung cysts, repeated spontaneous pneumothorax (collapsed lung), small skin bumps called fibrofolliculomas, and a higher chance of certain kidney tumors. In some people, a collapsed lung is the first sign that leads to testing for the FLCN gene and Birt-Hogg-Dubé syndrome. These variants confirm the diagnosis rather than simply raising risk.
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 have a direct effect on health and simply contribute to natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a confirmed diagnosis, especially when several genes and environmental factors are involved. In some situations, however, a single well characterized variant in a specific gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
With a harmful change in the FLCN gene, much of the risk is driven by the gene itself, especially for lung cysts, collapsed lung, and certain kidney tumors. Smoking and pressure changes such as scuba diving or unpressurized high-altitude flying can raise the chance of a collapsed lung. Regular kidney checks can help find problems early.
Inheritance of FLCN variants
FLCN gene variants linked to Birt-Hogg-Dubé syndrome are inherited in an autosomal dominant pattern. This means a parent carrying a disease-causing FLCN variant has a 50% chance of passing it on to each child, regardless of sex. In practical terms, the inheritance of the FLCN gene variants can affect multiple generations in a family. Since the FLCN gene is on chromosome 17, mothers and fathers can both pass it to sons or daughters.
What does my FLCN result mean for my family?
A harmful change in the FLCN gene is usually linked to a condition that can run in families in a dominant way, so close relatives such as parents, brothers, sisters, and children may also have the same gene change. Each child of someone with an FLCN change has a 1 in 2, or 50%, chance of inheriting it. Because of this, family members may also want to learn whether the result applies to them.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the FLCN gene, clinicians use genetic testing for FLCN variants on a blood or saliva sample. A lab reads the gene’s DNA code and checks for changes linked to Birt-Hogg-Dubé syndrome. Results may show a pathogenic variant, no relevant variant, or a variant of uncertain significance.
When should I consider getting a genetic test?
Genetic testing for the FLCN gene may be worth considering if you or close relatives have had repeated collapsed lungs, many lung cysts, certain kidney tumors, or small pale skin bumps on the face or upper body. A harmful FLCN change can confirm a hereditary condition that runs in families and helps guide kidney screening for relatives.
A genetic result is only one part of your health story
A genetic result may provide useful insight, but how much it can tell you varies by the condition and the type of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body functions. In some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is most helpful when viewed alongside other parts of care. In other situations, a genetic result may give a clear answer. In areas like medication response, genetic results can also help put individual experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in DNA can change how the body absorbs, breaks down, or responds to a drug. This helps explain why the same treatment works well for one person, seems less effective for another, or causes more side effects in someone else. These differences are common and are one part of the bigger picture, along with age, kidney and liver function, other medicines, and overall health.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way people respond 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 processes it. This information can support treatment decisions that are more informed and more individualized. To explore this topic further, you can learn more in the LearnHub.
Drugs influenced by the FLCN gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work or what side effects they may cause. Questions about medication response, side effects, or treatment choices are best discussed with your doctor.
History
Initially understood only through visible traits, later recognized as tied to a specific gene, FLCN entered the medical literature through Birt-Hogg-Dubé syndrome, first described in 1977 by three Canadian physicians. Families with shared skin findings helped doctors see that the condition could run from parent to child. In the years that followed, researchers mapped the cause to chromosome 17. A major step came in 2002, when the FLCN gene was identified as the gene linked to Birt-Hogg-Dubé syndrome. That discovery gave families a clearer genetic explanation and made more precise testing possible. Since then, research on the FLCN gene has steadily expanded, especially in inherited kidney and lung-related conditions.