The POLRMT gene helps mitochondria, the parts of cells that make energy, read their own DNA so cells can keep working. This gene plays an important role in energy production, especially in the brain, muscles, and eyes, which need steady fuel. If the POLRMT gene does not work properly, it can cause a mitochondrial condition with symptoms such as developmental delay, muscle weakness, eye movement problems, hearing changes, or seizures. Effects can vary widely from one person to another.
What is a gene?
A gene is a stretch of DNA that carries instructions your cells use to make molecules or regulate activities in the body. Some genes hold the directions for producing proteins, which are the functional parts of cells. Others mainly help determine when certain processes occur, where they occur, and how strongly they operate. Together, genes affect how the body develops and works, and they can influence how you respond to food, stress, or medications. To explore this topic further, you can find more in LearnHub.
Overview
POLRMTGene function
What if the gene works
The POLRMT gene helps mitochondria, the parts of cells that make energy, copy DNA instructions into RNA. This supports normal production of proteins your cells need to make energy.
Risk
What if the gene does not work
When the POLRMT gene does not work properly, it can cause a mitochondrial condition with delayed development, low muscle tone, weakness, poor growth, and feeding or movement problems. Effects can range from milder childhood difficulties to more severe early-onset disease.
Treatment
What does that mean for your treatment
No POLRMT-specific treatment or management approach is currently established for people with a pathogenic or loss-of-function variant in the POLRMT gene. Researchers are studying the POLRMT gene as a drug target in some cancers and in mitochondrial disease research, but this has not yet changed standard treatment choices for conditions linked to this gene.
Gene function
What if the gene works
Your mitochondria need the POLRMT gene to read the small set of genes they carry. This supports energy production in cells that work hard each day, including muscles, the heart, and the brain. Understanding how the POLRMT gene helps mitochondria make energy can make its everyday role easier to see.
POLRMT reads mitochondrial DNA and makes RNA copies from it. These RNA molecules let mitochondria use their genetic instructions during everyday cell activity.
Some of the RNA made by POLRMT serves as instructions, while some helps assemble proteins inside mitochondria. This supports the protein making steps needed for normal energy production.
POLRMT also makes short RNA starter pieces that help begin copying mitochondrial DNA. This gives mitochondria a starting point when they need to make new DNA.
POLRMT works with helper proteins to begin RNA production at the right places on mitochondrial DNA. This keeps mitochondrial gene activity organized and matched to the cell's energy needs.
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 variation in appearance, metabolism, or the way the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. In some cases, though, a variant changes how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
A clear way to understand how variants in the POLRMT gene affect mitochondrial RNA production is that many make the enzyme less stable, weaken its ability to bind mitochondrial DNA, or slow RNA output. Milder variants may leave some activity, while more disruptive variants can greatly reduce output or interfere with partner proteins. Less remaining activity can lead to greater mitochondrial dysfunction, and related features may appear earlier or be more pronounced.
How variants are linked to conditions
Variants in the POLRMT gene are linked to rare inherited mitochondrial disease, often described as combined oxidative phosphorylation deficiency. People with disease causing POLRMT variants may have developmental delay, low muscle tone, muscle weakness, or slowly worsening problems moving the eyes, sometimes called progressive external ophthalmoplegia. In discussions of how POLRMT gene variants are linked to conditions, doctors are referring to rare variants known to cause disease, not common genetic differences.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of being human and are found widely across the population. Most do not directly affect health and simply contribute to normal human variation. For many genes, having a variant associated with a condition points to a possible link rather than a certain diagnosis, particularly when several genes and environmental influences also play a role. Still, in some situations, one well understood variant in a particular gene is enough to establish 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 health risks related to the POLRMT gene. For many living with a POLRMT change, risk depends mainly on the exact variant and the health condition involved, so personal guidance from a doctor or genetic counselor can help put results in context.
Inheritance of POLRMT variants
For families learning how POLRMT gene variants are inherited, the pattern can differ by the specific condition and variant. POLRMT-related conditions have been reported with both autosomal dominant and autosomal recessive inheritance. In an autosomal dominant pattern, a parent with the variant can pass it to a child with a 50% chance in each pregnancy. In an autosomal recessive pattern, a child usually inherits one POLRMT gene variant from each parent, who are often unaffected carriers. The POLRMT gene is on chromosome 19, so these variants are inherited equally through either side of the family.
What does my POLRMT result mean for my family?
Changes in the POLRMT gene linked to health conditions are typically passed down in a recessive pattern, which means close relatives may also be carriers even if they do not have symptoms. Brothers and sisters could have the same condition or be carriers, depending on which gene changes they inherited. For parents, this usually means both carry one changed copy, and other relatives on each side of the family may also carry it.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the POLRMT gene, genetic testing for POLRMT variants usually analyzes DNA from a blood sample or cheek swab. A lab reads the gene's code and compares it with the usual sequence to look for changes that may help explain symptoms or confirm a diagnosis.
When should I consider getting a genetic test?
Testing for changes in the POLRMT gene may be considered when someone has signs of a rare mitochondrial condition, such as ongoing muscle weakness, poor coordination, developmental delay, seizures, or drooping eyelids and eye movement problems. It can also help when similar problems run in the family.
A genetic result is only one part of your health story
Genetic results can provide useful insight, but how much they reveal depends on the condition and the kind of variant involved. Many other factors, including lifestyle, environment, age, and medical history, influence how the body functions over time. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is most helpful 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 frame individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines. Some people break down a drug more slowly or more quickly, while others may be more or less sensitive to its effects. This helps explain why the same treatment can work well for one person but cause side effects or have less benefit in another. These differences are common and are one reason medication response can vary from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect a person’s response to medication. It studies connections between genes and drugs 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 personalized treatment decisions. You can read more about this topic in the LearnHub.
Drugs influenced by the POLRMT gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding how medicines are chosen or used, so general health or medication concerns are best discussed with your doctor or pharmacist.