The HRAS gene helps control how cells grow, divide, and respond to signals. If it does not work properly, growth messages can stay switched on, so cells may grow at the wrong time or in the wrong way. Some variants in the HRAS gene cause Costello syndrome, which can affect growth, development, the heart, and appearance. Other variants in the HRAS gene that arise during life are found in some cancers. Many variants are harmless, while a few may change how the gene guides cell growth.
What is a gene?
A gene is a stretch of DNA that gives your cells instructions for making molecules or regulating processes in the body. Some genes carry the instructions for producing proteins, the parts of cells that do much of the work. Other genes mainly guide when certain processes happen, where they happen, and how active they are. Together, genes affect how the body develops and works, and they can influence how you respond to food, stress, and medications. For a more detailed look at this topic, you can find more in the LearnHub.
Overview
HRASGene function
What if the gene works
The HRAS gene helps cells pass along growth signals. This supports controlled cell growth, division, and normal development.
Risk
What if the gene does not work
Variants in the HRAS gene can cause Costello syndrome, affecting growth, development, feeding, and the heart. Milder and more severe variants may change when features appear and how strong they are. Acquired HRAS variants are also linked to some cancers.
Treatment
What does that mean for your treatment
No HRAS-specific treatment or management approach is currently established in clinical guidelines. In cancer care, the HRAS gene is being studied as a drug target and biomarker, including farnesyltransferase inhibitors such as tipifarnib for selected tumors with HRAS variants.
Conditions associated with HRAS
Gene function
What if the gene works
Knowing what the HRAS gene does helps make sense of how cells handle everyday growth signals. It passes messages from the cell surface to the cell’s control systems. When this signaling is well balanced, cells can grow, divide, and mature in an orderly way.
The HRAS gene makes a protein that works like an on and off switch inside cells. It picks up cues from cell surface receptors and passes them inward.
Its protein helps cells respond to normal growth signals from their surroundings. This supports controlled cell growth and cell division during everyday tissue renewal.
Signals linked to the HRAS gene also help guide how some cells mature into their specific roles. This helps tissues develop the right balance of cell types.
Its protein switches signals on for a short time and then allows them to settle back down. This keeps cell communication orderly and easier for the body to coordinate.
What is a variant?
A genetic variant is a minor difference in the DNA sequence of a gene. These changes are common and help account for normal human diversity, such as differences in appearance, metabolism, or how the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. Sometimes, though, a variant changes how a gene functions more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Many variants in the HRAS gene make its protein overly active, leaving growth signals partly or strongly switched on when a cell should pause. Milder changes may raise signaling only a little, while more disruptive variants can keep it on longer or weaken normal control by other proteins. This functional range helps explain how HRAS gene variants affect cell signaling and why some are linked to earlier and more marked features in Costello syndrome.
How variants are linked to conditions
Certain pathogenic variants in the HRAS gene cause Costello syndrome, a rare condition that can affect growth, development, the heart, and cancer risk. A pathogenic HRAS gene variant causing Costello syndrome is the main well-established inherited link described in medical genetics. Separate acquired variants in the HRAS gene, not inherited from a parent, are also found in some cancers, including bladder, thyroid, and head and neck cancers.
A variant is not necessarily a diagnosis
Genetic variants are a usual feature of human biology and are widely found in the general population. Most do not directly affect health and simply reflect natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when multiple genes and environmental factors play a part. In some situations, though, 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?
There is not yet broadly confirmed evidence on specific factors that increase or reduce health risks linked to the HRAS gene itself. For many living with an HRAS-related condition, risk is driven mainly by the gene change, so regular follow-up and monitoring for complications are more important than lifestyle changes for altering that risk.
Inheritance of HRAS variants
Most inherited HRAS-related conditions follow an autosomal dominant pattern, which means one altered copy of the HRAS gene can be enough to cause the condition. For families asking how HRAS gene variants are inherited, a parent who carries a disease-causing variant could pass it to each child with a 50% chance. In practice, most people with a pathogenic variant in the HRAS gene have it because of a new (de novo) variant that was not inherited from either parent.
What does my HRAS result mean for my family?
For HRAS, a disease-causing result is usually linked to Costello syndrome, which follows a dominant inheritance pattern. This means a parent, child, brother, or sister could also carry the same change, so close relatives may wish to discuss family testing. Many HRAS changes in Costello syndrome happen for the first time in the child and are not inherited from either parent.
Genetic information
Genetic testing
How you find out about variants
To look for variants in the HRAS gene, genetic testing usually uses a blood or saliva sample. A lab reads the DNA and checks for changes in the HRAS gene, sometimes as part of a larger panel of genes linked to similar symptoms. Results can show whether an HRAS variant is present and may help clarify a diagnosis or a family finding.
When should I consider getting a genetic test?
Genetic testing for the HRAS gene may be considered when a baby or child has features that suggest Costello syndrome, such as feeding problems, developmental delay, loose skin, and heart concerns. It may also come up with a family history of this condition. In cancer care, tumor testing may check HRAS changes to help guide diagnosis or treatment planning.
A genetic result is only one part of your health story
A genetic result can be informative, but how much it reveals depends on the condition and the kind of variant involved. Over time, many factors shape how the body works, including lifestyle, environment, age, and medical history. For some conditions, especially those influenced 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 may give a clear answer. In areas like medication response, genetic results can also help make sense of individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body handles a medicine and how strongly you respond to it. Some people break down a drug faster, while others process it more slowly or are more sensitive to its effects. This helps explain why the same medication may work very well for one person, less well for another, or cause more side effects in someone else. These differences are common and are one part of why treatment response varies from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect a person’s response to medications. It studies the relationship between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes influence either how strongly a drug works or how the body processes it. This information can support more informed and more individualized treatment decisions. More on this topic is available in the LearnHub.
Drugs influenced by the HRAS gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding everyday medication choices, so any concerns about medicines, side effects, or treatment response are best discussed with your doctor. In cancer care, HRAS changes found in a tumor may sometimes help guide treatment planning, especially in some head and neck cancers.
History
The HRAS gene holds an important place in cancer genetics because it was one of the first human genes linked to cancer through gene changes. In the early 1980s, researchers identified altered forms of the HRAS gene in human bladder cancer cells, helping show that cancer can arise when normal growth control genes become overactive. This discovery changed how scientists thought about cancer, moving the field toward a genetic explanation of tumor development. Building on this early work, scientists uncovered more about the gene and related RAS family genes, which became central to cancer research. The HRAS gene also helped connect findings from animal tumor viruses with changes found directly in human cancers. These milestones made HRAS part of the foundation of modern molecular oncology.