The USP9Y gene is found on the Y chromosome and supports sperm production in the testes, so changes that stop it working can contribute to infertility. The protein made by this gene helps your cells manage proteins needed during sperm development. Some people with a USP9Y gene deletion have a very low sperm count or no sperm in semen, while others have milder effects.
What is a gene?
A gene is a stretch of DNA that gives your cells instructions for making molecules or for regulating activities in the body. Some genes carry the code for proteins, which do much of the work inside cells. Other genes mainly direct when certain processes happen, where they take place, 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. To explore this topic in greater detail, you can learn more in the LearnHub.
Overview
USP9YGene function
What if the gene works
In males, the USP9Y gene helps support normal sperm development in the testes. It makes a protein involved in how cells manage and recycle other proteins. This may help sperm forming cells work properly.
Risk
What if the gene does not work
Changes in the USP9Y gene can range from milder variants that partly reduce activity to more severe variants that stop it. This lowers or removes a protein that helps manage protein recycling in cells, especially the testes.
Treatment
What does that mean for your treatment
No USP9Y-specific treatment or management approach is currently established. In practice, care is guided by the person’s infertility pattern, and the USP9Y gene is mainly being studied as a contributor to male infertility rather than as a drug target that changes medication choices.
Conditions associated with USP9Y
Gene function
What if the gene works
In people with a Y chromosome, the USP9Y gene is most active in the testes, where sperm are made. It gives cells instructions for a protein that removes small control labels called ubiquitin from other proteins. This careful protein control supports the normal steps of sperm production.
The USP9Y gene helps remove ubiquitin tags (small labels that influence a protein's use or breakdown) from selected proteins. This lets cells adjust how long those proteins stay active and available.
In people with a Y chromosome, the USP9Y gene is active mainly in the testes during normal sperm production. Its protein supports the step by step changes that help developing sperm cells mature.
By fine tuning protein turnover, the USP9Y gene helps cells keep routine activity well coordinated. This is especially relevant in cells that will become sperm, which need carefully timed changes as they develop.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These differences are common and help create normal variation among people, such as differences in appearance, metabolism, or the way the body responds to environmental influences. Many variants do not cause any noticeable effects and are simply part of natural genetic diversity. 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
Changes in the USP9Y gene can shorten the protein, make it less stable, or reduce how well it works, which is how USP9Y gene variants affect protein function. More severe variants, including deletions or changes that stop the protein early, may leave little or no working protein, while milder variants can partly lower its activity. This range in effect is linked to wide differences in sperm production, from little measurable impact to no sperm seen in semen.
How variants are linked to conditions
Variants affecting the USP9Y gene have been linked to some forms of male infertility, especially Y linked spermatogenic failure with azoospermia or severe oligozoospermia. In research on how variants in the USP9Y gene are linked to conditions, the clearest association is reduced sperm production, but the effect can vary widely and some men carrying this gene change still have sperm present. These findings make the USP9Y gene most relevant in the evaluation of infertility rather than a broad range of other health conditions.
A variant is not necessarily a diagnosis
Gene variants are a normal feature of human biology and are widely found in the general population. Most have no direct impact on health and simply contribute to natural human variation. For many genes, carrying a variant connected with a condition indicates a possible association rather than a definite diagnosis, especially when more than one gene and environmental factors are involved. In some situations, though, a single well-characterized variant in a specific gene can be 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 lower health risk related to the USP9Y gene. In practice, changes in USP9Y have mainly been studied in some men with fertility problems, and personal risk can also be shaped by other genes and overall reproductive health.
Inheritance of USP9Y variants
USP9Y gene inheritance is tied to the Y chromosome. Variants in the USP9Y gene are therefore passed from father to son, and daughters do not inherit this gene because they do not receive a Y chromosome. This is called Y linked inheritance. In families, that means any inherited USP9Y gene change can only be seen in males along the paternal line.
What does my USP9Y result mean for my family?
If a disease-causing change in the USP9Y gene is confirmed, the family pattern is usually passed through the Y chromosome, from father to son. That means male relatives on the same father’s side of the family may share the change, while daughters do not inherit it. In families where it affects fertility, some male relatives may have similar trouble making sperm, though the effect can vary.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for USP9Y variants is done on a blood, saliva, or cheek swab sample. A lab analyzes the DNA of the USP9Y gene, often as part of Y chromosome testing, to look for missing pieces or other variants that may help explain reduced sperm production or infertility.
When should I consider getting a genetic test?
There is not yet a broadly established reason to test USP9Y on its own. In some men being checked for a very low sperm count or no sperm, doctors may look at this gene as part of broader Y chromosome testing, based on personal and family history.
A genetic result is only one part of your health story
Genetic results can be informative, but their meaning varies with the condition and the kind of variant found. Over time, factors like lifestyle, environment, age, and medical history also influence how the body functions. In some conditions, particularly those shaped by many genes, genetic information offers context rather than certainty and makes the most sense when considered with other parts of care. In other situations, a genetic finding may give a clear answer. For medication response, these results can also help make sense of individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Some people break down a drug more quickly, while others process it more slowly or are more sensitive to its effects. This helps explain why the same treatment can work well for one person, have less effect for another, or be more likely to cause side effects in someone else.
What is Pharmacogenetics?
Pharmacogenetics is the area of study that examines how genetic differences affect the way people respond to medications. It looks at links between genes and drugs to help explain why a treatment may work differently from one person to another. With many medicines, genes can influence how strongly a drug works or how the body handles it. This understanding can support treatment decisions that are more informed and more individualized. More on this topic is available in the LearnHub.
Drugs influenced by the USP9Y gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in how medicines work, so concerns about side effects, medication changes, or your general health are best discussed with your doctor.
History
USP9Y came to medical attention during efforts to understand why some men have very low sperm production or no sperm in semen. In the 1990s, researchers studying the Y chromosome identified this gene in a region linked to male infertility and first described it as DFFRY. Initially understood only through visible traits, later recognized as tied to a specific gene, USP9Y became part of the search for the causes of azoospermia and severe oligospermia. Early reports suggested that losing this gene could strongly affect fertility. Over time, scientists’ understanding of the gene’s function has changed. Later studies found that some men missing USP9Y could still father children, which reshaped how its role in infertility was interpreted.