The VARS2 gene helps mitochondria, the energy centers inside cells, make proteins needed to produce energy. If it does not work well, the brain, muscles, and heart may not get the energy they need, which can lead to early life symptoms such as low muscle tone, feeding problems, developmental delays, seizures, or heart muscle disease. People with two nonworking variants in the VARS2 gene typically have a mitochondrial condition that can range from severe in infancy to milder forms later in life.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or regulate processes throughout the body. Some genes provide the directions for producing proteins, which are the functional components of cells. Others are mainly involved in controlling when specific processes happen, where they take place, and how active they are. In combination, genes affect how your body grows and works, and they may also influence how you react to food, stress, and medications. For a deeper look at this topic, you can read more in the LearnHub.
Overview
VARS2Gene function
What if the gene works
The VARS2 gene helps mitochondria, the cell’s energy makers, build proteins. Its protein places the amino acid valine onto transfer RNA, a carrier molecule needed for normal energy production.
Risk
What if the gene does not work
Poor function of the VARS2 gene can cause a mitochondrial condition that limits cell energy, often leading to developmental delay, low muscle tone, seizures, and heart problems. Effects can range from milder to severe, with earlier onset meaning more features.
Treatment
What does that mean for your treatment
For pathogenic or loss-of-function variants in the VARS2 gene, no treatment or drug choice specific to VARS2 is currently established; care is based on a person’s symptoms.
Gene function
What if the gene works
Much of your daily energy depends on smooth work inside mitochondria, the parts of cells that make usable energy. The VARS2 gene supports this process by helping mitochondria build some of their own proteins. This background helps explain what the VARS2 gene does in mitochondria during everyday cell activity.
Inside mitochondria, the VARS2 gene helps attach valine, a protein building block, to a matching transfer RNA (a small helper used to build proteins). This gets the right ingredient ready for protein making.
By preparing this transfer RNA, the VARS2 gene supports protein production inside mitochondria. This helps the cell make key parts needed for its energy machinery.
Many cells depend on this steady mitochondrial protein-making process each day, especially cells in the brain, muscles, and heart. It helps mitochondria turn food and oxygen into usable energy.
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 human diversity, including differences in appearance, metabolism, or how the body responds to environmental factors. Many variants do not have any noticeable effect and are simply part of natural genetic variation. In some situations, though, 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
Changes in the VARS2 gene can make its protein unstable or less able to attach the amino acid valine to a helper RNA used to build proteins inside mitochondria. In plain terms, VARS2 gene variants and mitochondrial protein production are closely linked: milder variants may leave some activity, while more severe variants can sharply reduce or stop it. That spectrum can lower the cell’s energy-making capacity, and more disruptive variants are often linked to earlier and more severe mitochondrial disease.
How variants are linked to conditions
Pathogenic variants in the VARS2 gene cause a rare mitochondrial condition called combined oxidative phosphorylation deficiency 20, often described as VARS2-related mitochondrial disease. People with this diagnosis may have early developmental delay, low muscle tone, seizures, feeding problems, and sometimes hypertrophic cardiomyopathy. Some also develop lactic acidosis, movement problems, or breathing difficulties. Different variants in the VARS2 gene can lead to a wide range of symptoms and severity.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are widely found in the general population. Most do not have a direct effect on health and instead represent normal human variation. 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 are involved. 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?
For VARS2, risk is mainly shaped by the gene changes a person is born with, especially when both copies of the gene carry a harmful change. There is not enough evidence to say that diet, exercise, or other lifestyle factors lower or raise this genetic risk.
Inheritance of VARS2 variants
VARS2-related conditions are inherited in an autosomal recessive pattern. This means a person usually inherits one VARS2 variant from each parent, and both parents are typically healthy carriers. When both parents carry a VARS2 gene variant, each pregnancy has a 25% chance of being affected, a 50% chance of resulting in a carrier child, and a 25% chance of resulting in a child without the familial variants. In practice, how VARS2 gene variants are inherited often becomes clear only after testing shows the same family change on both sides of the family.
What does my VARS2 result mean for my family?
For VARS2-related disease, family members are usually affected through a recessive pattern, which means parents are often healthy carriers. Brothers and sisters may also be affected or may be carriers, and other relatives on both sides of the family can sometimes carry the same gene change. Because of this, close relatives may want to discuss the family result with their healthcare team when thinking about family planning or genetic testing.
Genetic information
Genetic testing
How you find out about variants
VARS2 genetic testing usually uses a blood sample, saliva, or a cheek swab to read the VARS2 gene and look for variants. It can show whether you carry a variant that may help explain symptoms or support a diagnosis, often through a larger gene panel or exome test.
When should I consider getting a genetic test?
Testing for changes in the VARS2 gene may be worth discussing if a baby or child has signs of a rare inherited condition that affects the body’s energy supply, such as developmental delay, seizures, low muscle tone, or heart muscle disease. It can also help when similar problems run in the family or when earlier testing suggests a mitochondrial condition.
A genetic result is only one part of your health story
Genetic findings can provide useful insight, although how much they reveal varies by the condition and the type of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how your body functions. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most meaningful when considered alongside other parts of care. In other situations, a genetic result can offer a clear answer. In areas such as medication response, these results may help place individual experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines. Small differences in genes can change how a drug is absorbed, broken down, or used by the body, so the same treatment may work better for one person than for another. This kind of variation is common and can influence both how well a medicine helps and how sensitive someone may be to side effects. Medication response also depends on other factors, including age, other health conditions, and other medicines.
What is Pharmacogenetics?
Pharmacogenetics explores how differences in genes can shape the way someone responds to medication. It studies gene drug relationships to help explain why the same treatment may work differently from one person to another. For many medicines, genes can affect how strongly a drug works or how the body processes it. This understanding can help support more informed, individualized treatment decisions. You can read more about this topic in the LearnHub.
Drugs influenced by the VARS2 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in showing how someone will respond to medicines, so concerns about side effects, treatment changes, or new symptoms are best discussed with your doctor.
History
VARS2 entered the medical literature relatively recently, when researchers studying children with unexplained mitochondrial disease linked the VARS2 gene to a distinct inherited condition. In recent decades, awareness of this gene’s role has grown. Early case reports connected variants in the VARS2 gene with problems affecting the brain, muscles, and heart, especially in infancy or childhood. From these first observations, research expanded steadily, and broader genetic sequencing helped doctors recognize more affected families worldwide. This work turned VARS2 from an obscure laboratory finding into an established cause of a rare mitochondrial condition.