The COX15 gene helps your cells build part of cytochrome c oxidase, a key step in turning food and oxygen into energy. This gene plays an important role in organs with high energy needs, such as the brain, muscles, and heart. If both copies do not work properly, a person can develop a condition in which cells do not make enough energy, with low muscle tone, developmental delay, movement problems, seizures, or heart muscle problems. Most people hear about the COX15 gene through genetic testing rather than public news stories.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or to regulate processes in the body. Some genes provide the directions for producing proteins, the parts of cells that do the work. Other genes mostly help decide when certain processes happen, where they happen, and how strongly they operate. Taken together, genes affect how the body grows and works, and they can influence how you respond to food, stress, or medicines. For a deeper look at this topic, you can read more in the LearnHub.
Overview
COX15Gene function
What if the gene works
The COX15 gene helps build a key part of complex IV, a protein complex in mitochondria, your cells’ energy centers. This supports normal energy production, especially in tissues like the heart and brain.
Risk
What if the gene does not work
Variants in the COX15 gene can cause mitochondrial disease, often affecting the heart and nervous system with cardiomyopathy, developmental delay, low muscle tone, or Leigh syndrome. Effects can range from milder to severe, influencing onset and features.
Treatment
What does that mean for your treatment
For pathogenic variants in the COX15 gene, no COX15-specific treatment or drug choice is currently established in clinical guidelines. Research is exploring ways to support mitochondrial energy production in COX15-related disease, but these approaches are not established treatments.
Conditions associated with COX15
Gene function
What if the gene works
Your cells need a steady power supply for movement, heartbeat, and brain signaling. The COX15 gene helps make one of the parts that mitochondria, the cell's energy centers, need for this job. Understanding what the COX15 gene does helps explain how your body turns oxygen and nutrients into usable energy.
The COX15 gene helps mitochondria make heme A, an iron-containing helper used by an enzyme called complex IV. This molecule sits inside the enzyme and helps it handle oxygen during energy production.
Its protein helps provide an essential piece for complex IV in the membrane where mitochondria make energy. This supports the enzyme's normal structure and lets it take part in the final steps of cellular energy production.
By supporting complex IV, the COX15 gene helps cells use oxygen as they turn food into usable energy. This supports oxidative phosphorylation (the process that makes most ATP, the cell's main energy source).
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These changes are common and help explain normal human diversity, such as differences in appearance, metabolism, or the way the body responds to environmental influences. Many variants do not have any noticeable effect and are simply part of natural genetic variation. In some instances, though, a variant can change how a gene functions more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the COX15 gene can make the protein unstable, shorten it, or greatly reduce its activity, so cells build too little complex IV, one part of the energy making system in mitochondria. This is how COX15 gene variants affect cell energy production. Some variants are milder and leave partial function, while more disruptive variants can leave little or no function and are often linked to earlier or more marked mitochondrial disease.
How variants are linked to conditions
Pathogenic variants in the COX15 gene can cause a rare mitochondrial condition, often called COX15-related mitochondrial disease, that may present in infancy with hypertrophic cardiomyopathy, developmental delay, low muscle tone, feeding problems, and high lactate levels. Some people with variants in the COX15 gene also develop Leigh syndrome, which affects the brain and nervous system. When clearly disease-causing variants are found in both copies of the gene, they can confirm this diagnosis.
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 simply contribute to natural human diversity. For many genes, carrying a variant associated with a condition suggests a possible link rather than a certain diagnosis, especially when several genes and environmental factors play a role. In some situations, however, 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 COX15, risk is mainly set by whether someone inherits harmful changes in both copies of the gene. There is not enough evidence to say that diet, exercise, or other everyday factors lower the chance of developing a COX15-related condition, although illness or other physical stress can sometimes make symptoms more noticeable in people already living with it.
Inheritance of COX15 variants
COX15-related conditions are inherited in an autosomal recessive pattern. This means a child usually inherits one COX15 gene variant from each parent, and both parents are often healthy carriers who do not have the condition themselves. For families asking how variants of the COX15 gene are inherited, each pregnancy between two carriers has a 25% chance of an affected child, a 50% chance of a child who is a carrier, and a 25% chance of a child with no inherited variant.
What does my COX15 result mean for my family?
For COX15-related conditions, family members are usually affected only when they inherit a changed copy from each parent. This often means parents are healthy carriers, while brothers and sisters may also be affected or may be carriers. Close relatives may want to learn whether the same COX15 change runs in the family, especially if there is a history of similar symptoms.
Genetic information
Genetic testing
How you find out about variants
COX15 genetic testing looks for variants in the COX15 gene using a blood sample, saliva, or sometimes a cheek swab. A lab reads the gene’s DNA code and compares it with the usual sequence to identify changes that may help explain symptoms or confirm whether a specific family variant is present.
When should I consider getting a genetic test?
Genetic testing for the COX15 gene may be considered when a baby or child has signs of a rare energy-production condition, such as developmental delay, weak muscles, seizures, breathing problems, or an enlarged heart. It can also help when there is a known COX15 variant in the family or a previous child with a similar condition.
A genetic result is only one part of your health story
A genetic result can provide helpful insight, but how much it explains varies based on the condition and the type of variant. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body functions. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is best viewed together with other parts of care. In other situations, a genetic result can give a clear answer. In areas such as 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 or how the medicine acts in the body, so the same treatment may work better for one person than another. These differences are common and can influence how much benefit someone gets or how likely they are to notice side effects.
What is Pharmacogenetics?
The field of pharmacogenetics examines how genetic differences can affect a person’s response to medications. It studies relationships 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 how strongly a drug works or how the body handles it. This information can support more informed, individualized treatment decisions. More detailed information on this topic is available in the LearnHub.
Drugs influenced by the COX15 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices, so any questions about medicines, side effects, or changes in your health are best discussed with your doctor.