The USP7 gene helps cells control and recycle proteins that guide brain development, growth, and repair of DNA, the body’s genetic instructions. If it does not work properly, these signals can become unbalanced. Pathogenic variants in the USP7 gene are linked to Hao-Fountain syndrome, a condition that often affects learning, speech, behavior, muscle tone, and sleep. Some people also have feeding difficulties, differences in growth, or low muscle strength.
What is a gene?
Genes are sections of DNA that give your cells instructions to make molecules or regulate activities in the body. Some genes carry the code for proteins, which do much of the cell’s work. Others mainly direct when certain activities happen, where they take place, and how active they are. Taken together, genes affect how your body develops and works, and they can also influence how you respond to food, stress, and medications. More on this topic is available in the LearnHub.
Overview
USP7Gene function
What if the gene works
The USP7 gene helps cells control protein levels by removing small tags that mark proteins for breakdown. This supports DNA repair, gene activity, immune signaling, and normal cell growth.
Risk
What if the gene does not work
Variants in the USP7 gene can cause Hao-Fountain syndrome, a condition that often affects development, speech, learning, and muscle tone. Effects range from milder to more severe, which can influence when features appear and how much support a person needs.
Treatment
What does that mean for your treatment
For pathogenic variants in the USP7 gene, no treatment or drug choice tied directly to USP7 is currently established in clinical guidelines. Care is based on a person’s symptoms and standard supportive treatment. The USP7 gene is also being studied as a possible drug target in some cancers, with USP7 inhibitors still in early research.
Conditions associated with USP7
Gene function
What if the gene works
Your cells rely on the USP7 gene to manage important proteins from moment to moment. It makes a protein that can remove small chemical tags called ubiquitin (a label that often marks proteins for recycling or reuse). Knowing what the USP7 gene does in cells helps explain how it supports DNA repair, growth, and everyday cell balance.
The protein from the USP7 gene removes small labels from selected proteins. This can spare them from being broken down or change where they work inside the cell.
USP7 helps steady several proteins that coordinate the response to DNA damage. By doing this, it supports accurate DNA repair so cells can keep their genetic instructions in good shape.
This gene also helps control the timing of cell growth and cell division by adjusting the levels of key regulator proteins. That balance helps cells move through normal checkpoints in an orderly way.
What is a variant?
A genetic variant is a small difference in the DNA sequence within a gene. These differences are common and help shape normal human diversity, such as variation in appearance, metabolism, or the way the body responds to environmental influences. Many variants do not have any noticeable effect and are simply part of natural genetic variation. In some cases, 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
USP7 gene variant effects often come from a reduced amount of USP7 protein, a misshapen protein, or weaker binding to partner proteins inside the cell. Some variants cause a near complete loss of function, while others only partly lower activity, so the impact can range from milder to more severe. In people with Hao-Fountain syndrome, larger functional losses may be linked to earlier or more pronounced features, although this can vary.
How variants are linked to conditions
Pathogenic variants in the USP7 gene cause Hao-Fountain syndrome, a genetic condition linked with developmental delay, speech and language difficulties, learning difficulties, low muscle tone, and behavior differences. In some people, USP7 gene changes linked to Hao-Fountain syndrome also go along with seizures, vision findings, sleep problems, or autism.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are widely found across the general population. Most do not directly affect health and simply contribute to normal human diversity. For many genes, carrying a variant connected with a condition suggests a possible link rather than a certain diagnosis, particularly when several genes and environmental factors also play a role. In some situations, though, one well characterized variant in a specific gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For USP7, there is not enough evidence to say that diet, exercise, or other everyday factors change the chance of having a USP7-related condition. Risk is mainly linked to whether a disease-causing USP7 variant is present, and it can be higher in a family if a parent carries that variant, sometimes even in only some egg or sperm cells.
Inheritance of USP7 variants
USP7-related Hao-Fountain syndrome follows an autosomal dominant inheritance pattern, which means one altered copy of the USP7 gene can be enough to cause the condition. If a parent carries a disease-causing USP7 variant, each child has a 50% chance of inheriting it. How variants of the USP7 gene are inherited can also include a new, de novo variant, meaning the change first appears in the child and was not inherited from either parent.
What does my USP7 result mean for my family?
For USP7, the main well-known condition is usually passed in a dominant pattern, so a parent, brother, sister, or child may also carry the same gene change. In many families, the change happened for the first time in the affected person, so it is not always inherited from a parent. If a parent carries the same USP7 change, each child can have a 1 in 2 chance of inheriting it.
Genetic information
Genetic testing
How you find out about variants
To look for changes in the USP7 gene, genetic testing reads DNA from a blood or saliva sample and checks it for variants. USP7 genetic testing may be done as part of a multigene panel or a broader DNA test that reads many genes at once. Results can show whether a variant is present, but they do not always predict symptoms or severity.
When should I consider getting a genetic test?
Genetic testing for the USP7 gene may be worth considering when a child has unexplained developmental delay, very limited speech, low muscle tone, autism, or behavior and learning differences. It can also be helpful when more than one family member has similar features.
A genetic result is only one part of your health story
A genetic finding can offer useful insight, but how much it reveals depends on the condition and the kind of variant involved. Many factors, including lifestyle, environment, age, and medical history, shape how the body functions over time. For some conditions, especially those influenced 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 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 because the body does not absorb, break down, or move every drug in the same way. These inherited differences are common and can help explain why one person gets good benefit from a treatment while another notices less effect or more side effects. Medication response is also shaped by age, other health conditions, and other medicines, so genes are one part of the overall picture.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way people respond to medications. It studies links between genes and drugs to help explain why the same treatment can work differently from one person to another. For many medicines, genes help shape how strongly a drug works or how the body processes it. This information can support treatment decisions that are more informed and more individualized. More about this topic is available in the LearnHub.
Drugs influenced by the USP7 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 changes in your health are best discussed with your doctor.
History
USP7 entered the research literature in the late 1990s, when scientists identified it through its interaction with a herpes simplex virus protein and gave it the name HAUSP. That early link to virology made the gene notable because it connected human cell biology with the way viruses take over cells. From these first observations, research expanded steadily. In the early 2000s, studies placed the USP7 gene into major cancer biology pathways, especially those involving the well-known p53 network, which drew broad interest across genetics and oncology. As genetic sequencing became more widely used, rare inherited USP7 variants were later recognized in people with neurodevelopmental conditions. Today, the gene is mainly known through this path from virus research to cancer studies and then to clinical genetics.