The TMEM126A gene helps mitochondria, the parts of cells that make energy, work properly, especially in the optic nerve. This gene helps your body support clear vision by helping nerve cells get the energy they need. If both copies of the gene do not work, a person can develop inherited optic atrophy, which often causes vision loss from childhood and can sometimes include hearing loss or other nerve symptoms.
What is a gene?
Genes are stretches of DNA that hold instructions your cells use to make molecules or regulate activities in the body. Some genes provide the directions for making proteins, the parts of cells that do much of the work. Other genes are mainly involved in controlling when certain processes happen, where they happen, and how strongly they run. Together, genes affect how the body develops and works, and they can influence how you respond to food, stress, or medications. If you want to go into this subject in more detail, you can find more in the LearnHub.
Overview
TMEM126AGene function
What if the gene works
The TMEM126A gene helps mitochondria, the cell’s energy centers, build complex I, a key part of energy production. This helps cells make steady energy, especially in tissues with high energy needs.
Risk
What if the gene does not work
Variants in the TMEM126A gene most often cause inherited optic atrophy, leading to gradually reduced vision from childhood or early adulthood. Some people also develop hearing loss. Milder and more severe variants can influence onset and which features appear.
Treatment
What does that mean for your treatment
At present, no TMEM126A-specific treatment or management approach is established for people with a pathogenic variant in the TMEM126A gene.
Conditions associated with TMEM126A
Gene function
What if the gene works
Much of your body's daily energy depends on healthy mitochondria, the parts of cells that turn food into usable power. The TMEM126A gene helps a key mitochondrial energy system form and work smoothly. This supports steady cell activity across the body. It also helps explain how the TMEM126A gene helps mitochondria make energy.
Its protein supports complex I, one of the first parts of the mitochondrial energy chain. This helps mitochondria pass along electrons in a controlled way and make ATP, the cell's main usable energy.
Its protein helps the pieces of complex I come together in the inner mitochondrial membrane. This lets the full energy unit form in the right place and work as a team.
Its protein sits in the inner mitochondrial membrane, where many energy producing proteins are found. This places it where it can support the buildup of complex I.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These changes are common and are part of normal human diversity, including differences in appearance, metabolism, or how the body responds to environmental influences. Many variants do not cause any noticeable effect and simply reflect natural genetic variation. Sometimes, though, a variant can change how a gene functions more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the TMEM126A gene often make the protein short, unstable, or missing, which can disrupt energy production inside mitochondria (the cell’s energy centers). In TMEM126A gene variants and optic atrophy, more disruptive changes usually leave little or no working protein, while milder variants may preserve some activity. This difference can influence how strongly retinal nerve cells are affected and, in some people, how early vision problems begin.
How variants are linked to conditions
Pathogenic variants in the TMEM126A gene cause an inherited form of optic atrophy, a condition that damages the optic nerve and leads to reduced vision, often from childhood. In medical genetics, the TMEM126A gene and optic atrophy are most clearly linked through autosomal recessive optic atrophy. Some people with TMEM126A-related optic atrophy also develop hearing loss.
A variant is not necessarily a diagnosis
Variants in genes are a routine feature of human biology and are widespread across the population. Most do not directly affect health and instead represent normal human diversity. 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 play a role. In contrast, in some situations, one well-characterized variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
There is not yet broadly confirmed evidence on specific factors that increase or reduce health risk related to the TMEM126A gene. For many living with a TMEM126A-related change, risk depends mainly on the exact gene change and whether one or both copies are affected, and a doctor or genetic counselor can help explain personal risk.
Inheritance of TMEM126A variants
Variants in the TMEM126A gene are inherited in an autosomal recessive pattern. This means a person usually needs to inherit two altered copies of the TMEM126A gene, one from each parent, to have a TMEM126A 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 who inherits neither variant. Sons and daughters are affected equally.
What does my TMEM126A result mean for my family?
For TMEM126A, family implications are usually those of a recessive inherited condition. Brothers and sisters may also have the condition or be healthy carriers, and parents are often carriers without symptoms. More distant relatives can be carriers too, especially in families where related conditions have appeared before.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for TMEM126A variants usually uses a blood or saliva sample. In TMEM126A genetic testing, a lab reads the DNA code in the TMEM126A gene to look for variants and can show whether you carry one or two variants.
When should I consider getting a genetic test?
Genetic testing for the TMEM126A gene may be worth considering if there is unexplained vision loss linked to the nerve that carries signals from the eye to the brain, especially when it starts in childhood or runs in the family. It can also help explain vision changes that happen with hearing loss.
A genetic result is only one part of your health story
A genetic result can provide valuable insight, but how much it reveals depends on the condition and the type of variant involved. Many other factors, including lifestyle, environment, age, and medical history, influence how the body functions over time. In some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most useful when considered alongside other parts of care. In other situations, a genetic result may offer a clear answer. In areas like medication response, genetic results can also help put individual 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 body, or reacts to it at its target. That helps explain why the same medication may work well for one person, do little for 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 people respond to medicines. By looking at links between genes and medications, it helps explain why the same treatment can work differently in different people. With many drugs, genes influence how the body processes a medicine or how strong its effects are. This information can support treatment decisions that are both more informed and more individualized. More detailed information on this topic is available in the LearnHub.
Drugs influenced by the TMEM126A gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medicine choice or dose. If you have side effects, questions about how a treatment is working, or concerns about your overall health, discuss them with your doctor.
History
TMEM126A entered medical genetics through studies of families with inherited vision loss, especially a form of optic atrophy seen in childhood. In the 2000s, researchers linked this gene to autosomal recessive optic atrophy in several families from North Africa, which made it an important clue in understanding rare inherited eye conditions. Initially understood only through visible traits, later recognized as tied to a specific gene, this work helped separate TMEM126A related disease from other causes of blurred vision and pale optic nerves. From these first observations, research expanded steadily. Later reports connected TMEM126A variants with a broader range of findings, including hearing changes in some people, showing that the early picture was only part of the story.