The CARS2 gene helps mitochondria, the parts of cells that make energy, build proteins they need to keep your body running. This gene plays an important role in supporting the brain, muscles, and other tissues that need a steady energy supply. If it does not work properly, cells may struggle to make enough energy, which can affect movement, learning, hearing, and brain function. Pathogenic variants in the CARS2 gene are linked to a rare inherited condition that may involve seizures, developmental delay, movement problems, and hearing loss.
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 provide the directions for producing proteins, the parts of cells that do the work. Others mainly control when certain processes happen, where they happen, and how strongly they are carried out. Together, genes affect how the body develops and works, and they can influence how you respond to food, stress, or medications. To go deeper into this topic, you can find more in the LearnHub.
Overview
CARS2Gene function
What if the gene works
The CARS2 gene helps mitochondria, your cells’ energy makers, build certain proteins.
It attaches cysteine, a protein building block, to a helper molecule needed to make those proteins.
Risk
What if the gene does not work
Variants in the CARS2 gene can cause a rare mitochondrial condition with seizures, developmental delay or regression, and movement problems. Milder to more severe variants may influence when symptoms begin and how strongly the nervous system is affected.
Treatment
What does that mean for your treatment
No treatment or management approach tied specifically to pathogenic variants in the CARS2 gene is currently established. Treatment is supportive and based on a person’s symptoms, not on a CARS2-targeted drug choice.
Conditions associated with CARS2
Gene function
What if the gene works
Inside your mitochondria, the parts of cells that help supply energy, the CARS2 gene helps prepare one protein building block for use at the right time. This supports the small protein making system that mitochondria run for themselves. When the CARS2 gene works normally, cells can keep this process orderly and steady.
Inside mitochondria, the CARS2 gene places cysteine onto a matching transfer RNA, a small helper that carries amino acids during protein building. This readies cysteine for the next step in making mitochondrial proteins.
By preparing cysteine in this way, the CARS2 gene supports protein production inside mitochondria. These proteins are part of the machinery mitochondria use for their routine work.
Many proteins made with help from the CARS2 gene are needed for the steps mitochondria use to release energy from food. This is part of how the CARS2 gene helps mitochondria make energy for day to day cell activity.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, and the way the body reacts to environmental influences. Many variants do not have any noticeable effect and are simply part of natural genetic variation. Sometimes, however, a variant can change how a gene works more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the CARS2 gene can change the shape or stability of its protein, making it harder for mitochondria to assemble some of the proteins they need for energy production. In plain terms, this is how CARS2 gene variants affect cell energy production. Milder variants may leave some enzyme activity, while more disruptive variants can sharply reduce it. That difference can influence how early and how strongly CARS2-related symptoms appear.
How variants are linked to conditions
Pathogenic variants in the CARS2 gene cause a rare inherited mitochondrial condition called combined oxidative phosphorylation deficiency 27. This CARS2 gene condition is typically linked to developmental delay, seizures, movement problems, muscle weakness, and, in some people, hearing loss. Symptoms often begin in infancy or childhood, though severity can vary widely from one person to another.
A variant is not necessarily a diagnosis
Genetic variants are a common and normal feature of human biology. Most do not directly affect health and simply contribute to natural differences among people. For many genes, having a variant associated with a condition points to a possible link rather than a certain diagnosis, especially when several genes and environmental factors are involved. In some situations, though, one well-characterized variant in a specific gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For CARS2, risk is mainly inherited rather than caused by lifestyle. The chance is highest when both parents carry a harmful CARS2 change, so family history and parents who are blood relatives can raise the chance in a child. Once someone has two nonworking copies, daily habits do not meaningfully change whether the condition develops.
Inheritance of CARS2 variants
CARS2-related conditions are inherited in an autosomal recessive pattern. This means a person usually inherits one altered copy of the CARS2 gene from each parent, and both parents are typically unaffected carriers. For families looking into the inheritance of CARS2 gene variants, when both parents carry a variant, each pregnancy has a 25% chance of the child inheriting both altered copies, a 50% chance of being a carrier, and a 25% chance of inheriting neither altered copy. This inheritance pattern is the well-established one for the condition linked to the CARS2 gene.
What does my CARS2 result mean for my family?
Changes in the CARS2 gene are linked to a rare inherited condition that usually runs in families in a recessive pattern. For family members, this often means parents can be healthy carriers, and brothers or sisters may also be affected or be carriers. Close relatives may want to learn whether the same gene change is present in their family.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the CARS2 gene, a lab can analyze DNA from a blood sample, saliva, or a cheek swab. This testing for CARS2 gene variants reads the gene's code and checks for changes linked to mitochondrial disease. Results may show a pathogenic variant, a benign variant, or a variant of uncertain significance.
When should I consider getting a genetic test?
Genetic testing for the CARS2 gene may be considered when a child or adult has unexplained seizures, developmental delay or loss of skills, movement problems, or other signs of a rare inherited condition affecting the body’s energy supply. It can also be helpful if similar problems have affected a brother, sister, or other close relative.
A genetic result is only one part of your health story
A genetic finding can provide useful information, but how much it explains varies by the condition and the type of variant involved. How the body works over time is also shaped by factors such as lifestyle, environment, age, and medical history. 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 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, so the same treatment may work better for one person than for another. These differences are common and can influence how much benefit someone gets or how sensitive they are to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines the way 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. For many drugs, genes influence both how the body handles the medicine and how strong its effects may be. This information can support treatment choices that are more informed and more tailored to the individual. More detail on this topic is available in the LearnHub.
Drugs influenced by the CARS2 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work or which side effects someone may have, so any concerns about your health or medications are best discussed with your doctor.