The EARS2 gene helps mitochondria, the energy centers inside cells, make proteins needed for steady energy production. If this gene does not work properly, cells may struggle to make enough energy, especially in the brain and muscles. Certain variants in the EARS2 gene are linked to a rare inherited condition that can cause developmental delay, low muscle tone, feeding problems, seizures, and changes on brain scans. Symptoms and severity can vary from person to person.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or regulate activities in the body. Some genes give the directions for producing proteins, the parts of cells that do much of the work. Others mainly help determine when certain processes happen, where they occur, 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. For a deeper look at this topic, you can learn more in the LearnHub.
Overview
EARS2Gene function
What if the gene works
The EARS2 gene helps mitochondria, your cells’ energy makers, build proteins. This supports energy production, especially in tissues with high energy needs such as the brain and muscles.
Risk
What if the gene does not work
DNA changes in the EARS2 gene can cause a mitochondrial brain condition, often with developmental delay, feeding problems, low muscle tone, seizures, and MRI changes. Effects range from milder childhood forms to more severe early-onset illness, depending on the variant.
Treatment
What does that mean for your treatment
No EARS2-specific treatment or management approach is currently established, so care is supportive and guided by the person’s symptoms rather than by a drug choice tied to the EARS2 gene.
Conditions associated with EARS2
Gene function
What if the gene works
Your cells need a steady supply of energy for the brain, muscles, and other organs to work each day. The EARS2 gene helps mitochondria, the cell's energy centers, make some of their own proteins. This supports routine energy production across the body.
Inside mitochondria, the EARS2 gene attaches glutamate, an amino acid, to transfer RNA (a small helper molecule used to build proteins). This readies that helper for the next step in protein making.
This step is central to how the EARS2 gene helps mitochondria make proteins for energy production. It helps the cell place the right amino acid where it belongs as these proteins are assembled.
Many of the proteins made with help from the EARS2 gene are used in the mitochondria's energy system. By supporting their production, this gene helps cells turn food and oxygen into usable energy.
What is a variant?
A genetic variant is a slight difference in the DNA sequence within a gene. These differences are common and are part of normal human diversity, including differences in appearance, metabolism, and the way the body responds to environmental influences. Many do not lead to any noticeable effect and simply represent natural genetic variation. Sometimes, though, a variant changes how a gene works more significantly and can contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the EARS2 gene can change the shape, stability, or activity of a protein that helps mitochondria make their own proteins. This helps explain how EARS2 gene variants affect cell energy production: milder variants may leave some activity, while more disruptive variants can sharply reduce the protein or stop it from working. When the loss of function is greater, EARS2-related disease often appears earlier or with more pronounced features, although the pattern can vary.
How variants are linked to conditions
Pathogenic variants in both copies of the EARS2 gene are linked to LTBL and cause this rare inherited condition. LTBL stands for leukoencephalopathy with thalamus and brainstem involvement and high lactate, and it is also known as combined oxidative phosphorylation deficiency 12. Severity can vary, but affected children often have developmental delay, feeding difficulties, weakness, or seizures. A diagnosis is confirmed when testing finds pathogenic variants in both copies of the gene.
A variant is not necessarily a diagnosis
Genetic variants are a common and expected part of human biology across the general population. Most do not directly affect health and simply reflect natural human diversity. For many genes, having a variant associated with a condition points to a possible link rather than a confirmed diagnosis, particularly when several genes and environmental influences play a role. Still, in certain situations, one well understood variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For EARS2, risk is mainly tied to genetics: a child is affected when they inherit a changed copy of the gene from each parent. There is not broadly confirmed evidence that lifestyle or environmental factors meaningfully increase or lower this gene-related risk, so people with family concerns should speak with a doctor or genetic counselor.
Inheritance of EARS2 variants
Variants in the EARS2 gene are inherited in an autosomal recessive pattern. This means a person usually has to inherit two disease-causing EARS2 variants, one from each parent, to have an EARS2-related condition. Parents who each carry one variant are typically unaffected carriers, and with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a child who is a carrier, and a 25% chance of having a child with neither variant. In families asking how EARS2 gene variants are inherited, this pattern means sons and daughters are affected equally.
What does my EARS2 result mean for my family?
For families affected by EARS2, the condition is usually passed down in a recessive pattern, which means parents are often healthy carriers. Brothers and sisters may also be affected or may be carriers, and other close relatives could be carriers too. This can matter for future pregnancies and for relatives who want to understand their own chance of having a child with the condition.
Genetic information
Genetic testing
How you find out about variants
Finding out whether you carry a variant in the EARS2 gene usually involves genetic testing for variants in the EARS2 gene using a blood sample or cheek swab. A lab reads the DNA sequence of the EARS2 gene and compares it with the usual sequence to look for changes that may help explain symptoms or confirm a suspected inherited condition.
When should I consider getting a genetic test?
Genetic testing for the EARS2 gene may be considered when a baby or child has signs of a rare inherited brain condition, such as developmental delay, low muscle tone, movement problems, or brain scan changes that fit this pattern. It can also help if there is a family history of the condition or a known EARS2 variant in the family.
A genetic result is only one part of your health story
Genetic findings can be informative, but how much they explain depends on the condition and on the specific kind of variant. Over time, the way the body works is shaped by many factors, including lifestyle, environment, age, and medical history. For some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is most useful when considered with other parts of care. In other situations, a genetic result can offer 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 people respond to medicines. Small differences in DNA can change how the body breaks down a drug, moves it through the body, or responds to it at its target. This helps explain why the same medication may work well for one person, have less effect for another, or cause more side effects in someone who is more sensitive to it.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect the way a person responds to medication. It looks at links between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes can influence both how strongly a drug works and how the body processes it. This understanding can support more informed, more individualized treatment decisions. More on this topic is available in the LearnHub.
Drugs influenced by the EARS2 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in medication response, so most treatment decisions are not based on it. If you have side effects, questions about a new prescription, or concerns about your health, talk with your doctor or pharmacist.
History
In recent decades, awareness of the EARS2 gene’s role has grown through research on rare inherited neurologic conditions. The gene entered the medical literature in a more visible way when researchers linked EARS2 variants to a condition now known as leukoencephalopathy with thalamus and brainstem involvement and high lactate, often shortened to LTBL. From these first observations, research expanded steadily, helping clinicians recognize that people with similar brain imaging findings and early symptoms could share the same genetic cause. Scientific classifications changed as researchers learned more about the gene, especially as wider genetic testing made diagnosis more precise. Although EARS2 has not become a public facing gene in the way some cancer or Alzheimer’s genes have, its discovery added an important piece to the history of mitochondrial disease genetics.