The IARS2 gene helps mitochondria, the cell’s energy centers, make proteins they need to produce energy. This gene plays an important role in tissues that use a lot of energy, such as the brain, muscles, eyes, and inner ear. If a person carries two nonworking variants in the IARS2 gene, cells may struggle to meet energy needs, which can lead to a mitochondrial condition with poor growth, muscle weakness, hearing or vision problems, anemia, or developmental differences.
What is a gene?
Genes are sections of DNA that give your cells instructions for making molecules or regulating processes in the body. Some genes carry the directions for producing proteins, which are the working parts of cells. Others mainly help control when certain processes happen, where they happen, and how active they are. Taken together, genes influence how the body develops and functions, and they can affect how you respond to food, stress, and medications. For a deeper look at this topic, you can find more in the LearnHub.
Overview
IARS2Gene function
What if the gene works
The IARS2 gene helps mitochondria, your cells’ energy makers, build proteins by attaching isoleucine to transfer RNA (a helper molecule used in protein building). This supports normal energy production, especially in tissues with high energy needs.
Risk
What if the gene does not work
Variants in the IARS2 gene can disrupt mitochondrial energy production. Depending on whether they are milder or more severe, they may cause a spectrum from cataracts and hearing loss to growth problems, muscle weakness, nerve problems, and delayed development.
Treatment
What does that mean for your treatment
No treatment or drug choice is currently guided specifically by a pathogenic or loss-of-function variant in the IARS2 gene. The IARS2 gene is also being studied in early cancer research as a possible growth-related target, but this has no current role in routine care.
Conditions associated with IARS2
Gene function
What if the gene works
Inside your cells, the IARS2 gene helps mitochondria make proteins. Mitochondria are the parts of cells that produce much of your body’s energy. Understanding how the IARS2 gene works helps explain how cells keep a steady energy supply for everyday activities.
The IARS2 gene attaches isoleucine, a protein building block, to transfer RNA (a small carrier molecule) inside mitochondria. This prepares the right ingredient for mitochondrial protein production.
This step helps mitochondria place isoleucine in the right spots as they build proteins. It supports steady, accurate protein production in these energy-producing parts of the cell.
Mitochondria use the proteins they make to help turn food and oxygen into usable energy. By supporting this process, the IARS2 gene helps cells meet everyday energy needs.
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 the normal diversity seen in humans, including differences in appearance, metabolism, and how the body responds to environmental influences. Many do not have any noticeable effect and simply represent natural genetic variation. In some cases, though, a variant can more substantially change how a gene functions and may contribute to, or cause, a genetic condition.
Genetic variants
What if the gene does not work
Variants in the IARS2 gene can change the enzyme’s shape, stability, or working part, making it less able to load isoleucine onto the RNA helper needed for mitochondrial protein production. How variants in the IARS2 gene affect mitochondrial protein production depends on the change itself. Some leave partial activity, while more disruptive variants sharply reduce or stop enzyme function, which can be linked to earlier onset and broader features.
How variants are linked to conditions
Pathogenic variants in the IARS2 gene are linked to a rare inherited condition called CAGSSS syndrome, one of the main health conditions linked to IARS2 gene variants. People with this diagnosis may have cataracts, hearing loss, short stature, delayed puberty, nerve symptoms, and changes in bone growth. Other severe IARS2-related conditions have also been reported, including early-onset brain and muscle involvement, showing that symptoms can vary widely from person to person.
A variant is not necessarily a diagnosis
Genetic variants are a normal feature of human biology and are common in the general population. Most do not have a direct effect on 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 also play a role. 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?
There isn't yet broadly confirmed evidence on specific factors that increase or reduce risk related to the IARS2 gene. For many living with an IARS2 gene change, health effects mainly depend on the exact change and whether one or both copies of the gene are affected. Anyone with concerns about personal or family risk should speak with a doctor or genetic counselor.
Inheritance of IARS2 variants
IARS2-related conditions are inherited in an autosomal recessive pattern. This means a child usually inherits one IARS2 variant from each parent, and the parents are typically healthy carriers. When both parents carry an IARS2 variant, each pregnancy has a 25% chance of the child inheriting both variants and being affected, a 50% chance of being a carrier, and a 25% chance of inheriting neither variant. For families asking how IARS2 variants are inherited, this pattern means boys and girls are affected at similar rates.
What does my IARS2 result mean for my family?
For IARS2, the main family implication is usually a recessive pattern, which means parents are often healthy carriers and brothers or sisters may also be affected or be carriers. Close relatives may want to learn whether the same gene change runs in the family, especially if there are similar hearing, growth, muscle, or developmental concerns. Children of someone with an IARS2-related condition are usually carriers unless the other parent also carries an IARS2 change.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for variants in the IARS2 gene uses a blood or saliva sample, which a lab reads to look for changes in the DNA code. This is how you find out about IARS2 variants: testing may be done in a multigene panel or broader sequencing and can confirm whether a disease-causing variant is present.
When should I consider getting a genetic test?
Consider IARS2 genetic testing when a child or adult has unexplained cataracts, hearing loss, growth problems, muscle weakness, nerve symptoms, or other signs of a condition that affects how cells make energy, especially if similar problems run in the family. Testing can help confirm whether IARS2 is the cause.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but what it can tell you varies by the condition and the specific type of variant. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body functions. In some conditions, especially those affected by many genes, genetic information provides context rather than certainty and is most helpful when viewed together with other parts of care. In other situations, a genetic result may offer a clear answer. In areas like medication response, genetic results can help put personal experiences into context.
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 bloodstream, or responds to it at its target. This helps explain why the same medication may work well for one person, have less effect in another, or cause more side effects in someone who is more sensitive to it.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes affect the way a person responds to medications. It studies gene and drug patterns 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 handles it. This information can support more informed and more individualized treatment decisions. You can learn more about this topic in the LearnHub.
Drugs influenced by the IARS2 gene
When should I seek medical advice?
There isn't yet a broadly confirmed role for this gene in guiding medicine choices, so if you have side effects, trouble with treatment, or questions about any medicine, it is best to speak with your doctor.