The STK4 gene helps control how immune cells grow, survive, and clear out damaged cells. If this gene does not work properly, the immune system may become weak, which can lead to repeated infections, mouth sores, skin problems, and a higher chance of certain blood cancers. This gene plays an important role in keeping tissues balanced by guiding when cells should divide and when they should die off. Pathogenic variants in both copies of the STK4 gene can cause a rare inherited immune condition.
What is a gene?
Genes are stretches of DNA that provide instructions your cells use to make molecules or direct activities in the body. Some genes carry the code for producing proteins, which do the work inside cells. Others are mainly involved in regulating when certain processes happen, where they happen, and how active they are. As a group, genes affect how the body grows and works, and they can influence how you respond to food, stress, or medications. More detailed information on this topic is available in the LearnHub.
Overview
STK4Gene function
What if the gene works
The STK4 gene helps control how cells grow, divide, and die when needed. It also supports immune cells, especially T cells, so your body can respond to infections and keep tissues balanced.
Risk
What if the gene does not work
Damaging variants in the STK4 gene can cause an inherited immune condition with low T cell counts, recurrent infections, and sometimes persistent mouth sores. Milder to more severe variants may affect when symptoms start and how strongly they show up.
Treatment
What does that mean for your treatment
No treatment or management approach tailored to the STK4 gene is currently established. In research, the STK4 gene is being studied as part of the Hippo signaling pathway, including as a possible biomarker or drug target in some cancers.
Conditions associated with STK4
Gene function
What if the gene works
The STK4 gene helps your cells balance growth, survival, and routine cleanup. It is part of a signaling network that tells cells when to divide, when to pause, and when to remove older cells. Understanding how the STK4 gene works in your cells helps explain how tissues stay organized over time.
The STK4 gene is part of the Hippo pathway (a cell growth control system). It helps keep cell growth and cell division in balance so tissues grow in an orderly way.
Its protein works as a kinase, an enzyme that adds small phosphate tags to other proteins. These tags act like switches that pass growth and survival messages through the cell.
This gene helps cells carry out programmed cell death, a normal process that removes worn out or damaged cells. That steady turnover helps the body renew tissues and maintain healthy cell numbers.
STK4 activity helps cells respond to nearby cells and their surroundings. This supports normal tissue structure and helps cells behave in the right place at the right time.
What is a variant?
A genetic variant is a small change in the DNA sequence within a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, and how the body responds to environmental influences. Many have no noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can change how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Many variants in the STK4 gene make the STK4 protein shorter, unstable, or unable to turn on its usual targets inside immune cells. In how STK4 gene variants affect protein function, the main pattern is a spectrum: some changes partly reduce signaling, while more disruptive variants can remove activity almost completely. This can weaken cell survival and control of cell death, and the more severe loss of function is often linked to earlier or more marked features of STK4 deficiency.
How variants are linked to conditions
Pathogenic variants in the STK4 gene cause a rare inherited immune condition often called STK4 deficiency. People with this diagnosis may have repeated bacterial, viral, or fungal infections, ongoing warts or molluscum skin lesions, yeast infections, and low white blood cell counts. STK4 gene variants linked to conditions have also been associated with a higher chance of Epstein-Barr virus related lymphoproliferation and lymphoma.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widespread in the general population. Most do not directly affect 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 definite diagnosis, especially when several genes and environmental factors play a role. In some situations, though, a single well characterized variant in a particular gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For STK4, risk is mainly linked to whether someone has disease-causing changes in both copies of the gene, rather than to clear lifestyle factors. There is not yet broadly confirmed evidence on specific outside factors that increase or reduce STK4-related risk, so people with questions about their personal risk should speak with a doctor or genetic counselor.
Inheritance of STK4 variants
STK4-related conditions are inherited in an autosomal recessive pattern. This means a person usually develops the condition only when both copies of the STK4 gene carry a disease-causing variant, with one altered copy inherited from each parent. Parents who each carry one STK4 gene variant are often unaffected carriers. In families learning how STK4 gene variants are inherited, each pregnancy between two carriers has a 25% chance of producing a child with the condition, a 50% chance of producing a carrier child, and a 25% chance of producing a child without the familial variant.
What does my STK4 result mean for my family?
For STK4, family implications usually follow a recessive pattern. This often means parents are healthy carriers, and brothers or sisters may also be affected or may be carriers even if they feel well. Other close relatives, such as aunts, uncles, and cousins on both sides, may also carry the same gene change in the family.
Genetic information
Genetic testing
How you find out about variants
To look for changes in the STK4 gene, doctors use STK4 genetic testing on a blood sample, saliva sample, or cheek swab. The lab reads the gene's DNA code and checks for variants, sometimes alongside many other genes, to show whether a variant is present.
When should I consider getting a genetic test?
Consider STK4 testing if you or your child has repeated serious infections, persistent warts, frequent fungal infections, low white blood cell counts, or a family history of a rare inherited immune condition linked to this gene. It can also help clarify the cause when these problems start in childhood.
A genetic result is only one part of your health story
A genetic finding can provide useful insight, yet how much it reveals 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. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is most useful when viewed alongside other parts of care. In other situations, a genetic result can give a clear answer. In areas like medication response, it can also help frame individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in genes can change how the body breaks down a drug, moves it through the body, or responds to it at its target, so the same treatment may work differently from one person to another. This is common and can influence how much benefit a medicine gives, as well as how sensitive someone may be to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines the ways genetic differences shape a person’s response to medicines. By studying links between genes and medications, it helps explain why the same treatment can affect people differently. With many drugs, genes influence either how powerfully a medicine works or how the body handles it. This information can support treatment choices that are better informed and more individualized. More detail on this subject is available in the LearnHub.
Drugs influenced by the STK4 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication response, so questions about your medicines, side effects, or new symptoms are best discussed with your doctor.
History
The STK4 gene entered research through basic cell biology studies in the 1990s, when scientists identified a related protein called MST1 while mapping signaling pathways inside cells. Its place in a larger network became clearer as work on the Hippo pathway grew, linking STK4 to a major shift in how researchers understood growth control. From these first observations, research expanded steadily. In the late 2000s, doctors also began reporting people with inherited STK4 variants and recurrent infections, which established the gene’s clinical importance. That connection helped move STK4 from a laboratory finding to a gene recognized in human disease. Over time, this history placed the STK4 gene at the crossroads of both cancer biology and immune system research.