The SURF1 gene helps mitochondria, the parts of cells that make energy, build an enzyme needed for energy production. The protein made by this gene helps your cells turn oxygen and food into usable energy, especially in the brain and muscles. Pathogenic variants in both copies of the SURF1 gene cause SURF1-related Leigh syndrome, a mitochondrial condition in which the body cannot meet energy needs well. Children often develop slowed development, loss of skills, weak muscle tone, movement problems, and feeding or breathing difficulties.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or regulate processes in the body. Some genes hold the directions for producing proteins, the parts that do much of the cell’s work. Other genes mainly help determine when certain processes happen, where they take place, and how strongly they run. Taken together, genes affect how the body develops and works, and they can also influence how you respond to food, stress, or medications. For a more detailed explanation of this topic, you can find more in the LearnHub.
Overview
SURF1Gene function
What if the gene works
The SURF1 gene helps mitochondria, the cell's energy centers, put together complex IV, a key step in making energy. This supports steady energy supply, especially in the brain and muscles.
Risk
What if the gene does not work
Disease-causing variants in the SURF1 gene most often cause Leigh syndrome, a mitochondrial condition that affects the brain, muscle tone, movement, and breathing. Milder and more severe variants can influence when symptoms begin and how strongly they affect daily life.
Treatment
What does that mean for your treatment
No SURF1-specific treatment or drug-choice approach is currently established in clinical guidelines. Care is supportive and may include standard mitochondrial disease measures, but these are not tailored to the SURF1 gene itself. The SURF1 gene is also being studied in experimental mitochondrial therapies, including early gene replacement research.
Conditions associated with SURF1
Gene function
What if the gene works
Your cells need a constant supply of energy for movement, growth, and repair. The SURF1 gene helps mitochondria, the parts of cells that make most of this energy, assemble an important energy unit called complex IV. When this step runs smoothly, cells can use oxygen to support everyday body functions.
Inside mitochondria, the SURF1 gene helps assemble complex IV, a key part of the cell’s energy chain. This gives the complex the right structure so it can join the rest of the energy system.
Complex IV is the step that passes electrons to oxygen at the end of energy production. By helping this step come together, SURF1 supports efficient energy release from food.
This work is especially important in tissues that need steady energy, such as the brain, muscles, and heart. When mitochondria run smoothly, these cells can keep up with routine daily demands.
What is a variant?
A genetic variant is a small difference in the DNA sequence within a gene. Variants are common and help explain normal human diversity, such as differences in appearance, metabolism, or the body’s response to environmental influences. Many do not produce any noticeable effect and simply represent natural genetic variation. In some instances, though, a variant can more strongly change how a gene functions and may contribute to, or cause, a genetic condition.
Genetic variants
What if the gene does not work
Variants in the SURF1 gene can lower or eliminate SURF1 protein production, which disrupts assembly of cytochrome c oxidase, a key part of the cell's energy system. Some changes leave a little protein activity, while more severe variants cause near complete loss, so SURF1 gene variants can affect Leigh syndrome severity and the age when problems begin. Truncating variants often have a larger functional effect than missense variants, though this can vary.
How variants are linked to conditions
Pathogenic variants in the SURF1 gene cause Leigh syndrome, a rare inherited mitochondrial condition. In practice, the conditions linked to SURF1 gene variants are centered on this diagnosis rather than a wide range of unrelated diseases. Symptoms usually begin in infancy or early childhood, and finding disease-causing variants in both copies of the gene can confirm the diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are common in the general population and are a normal feature of human biology. 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 definite diagnosis, especially when several genes and environmental factors play a role. In some situations, though, a single well-characterized variant in a specific gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For SURF1-related disease, risk is mainly shaped by inheritance: a child is affected when they inherit a harmful SURF1 change from both parents. Risk is higher in families with a known SURF1 variant or when parents are related by blood, because they are more likely to carry the same change.
Inheritance of SURF1 variants
Variants in the SURF1 gene are inherited in an autosomal recessive pattern. This means a child usually develops a SURF1 related condition only after inheriting one nonworking copy of the gene from each parent. Parents who each carry one SURF1 variant are usually unaffected themselves, and with each pregnancy there is a 25% chance of having an affected child, a 50% chance the child will be a carrier, and a 25% chance the child will inherit neither variant. This is the usual answer to how variants of the SURF1 gene are inherited.
What does my SURF1 result mean for my family?
For SURF1, family implications usually follow a recessive pattern. Parents of an affected child are often healthy carriers, and brothers or sisters may also be affected or may be carriers. Other close relatives can sometimes carry the same gene change too, so the result may matter beyond one person in the family.
Genetic information
Genetic testing
How you find out about variants
Testing for changes in the SURF1 gene uses blood, saliva, or a cheek swab to read DNA and look for variants. SURF1 genetic testing can help confirm a condition linked to SURF1 variants or clarify carrier status in a family, and results may show a variant, no variant, or an uncertain finding.
When should I consider getting a genetic test?
Genetic testing for the SURF1 gene may be worth considering when a baby or child has signs of Leigh syndrome, such as developmental loss, weak muscles, trouble feeding, breathing problems, or seizures. It can also help when there is a family history of Leigh syndrome or a known SURF1 change in the family.
A genetic result is only one part of your health story
How much a genetic result can tell you depends on both the condition and the type of variant involved, even though it can provide valuable insight. Lifestyle, environment, age, and medical history, among other influences, also shape how the body works over time. In some conditions, especially ones affected by many genes, genetic information provides context rather than certainty and is most useful when viewed alongside other parts of care. In other situations, a genetic result can offer a clear answer. In areas such as medication response, it can also help place personal experiences in perspective.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. This happens because inherited differences can change how the body absorbs, breaks down, transports, or responds to a drug. As a result, the same medication may work better for some people, have less effect in others, or cause side effects more easily.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape a person’s response to medications. It studies the relationship between genes and drugs 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 handles it. This information can support treatment decisions that are more informed and more individualized. To explore this subject in greater detail, you can learn more in the LearnHub.
Drugs influenced by the SURF1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in how people respond to medicines, so questions about symptoms, treatment side effects, or medication choices are best discussed with your doctor.
History
SURF1 entered medical genetics through research on Leigh syndrome, a severe inherited condition affecting energy production in cells. In the late 1990s, researchers identified variants in the SURF1 gene as a cause of a form of Leigh syndrome linked to cytochrome c oxidase deficiency, helping connect a specific gene to a long-recognized mitochondrial disease. The gene itself had already been mapped within the “surfeit” gene cluster, an unusual region where several unrelated genes sit very close together. From these first observations, research expanded steadily. SURF1 became important in the study of mitochondrial disease because it helped clarify why some children with Leigh syndrome share a similar pattern on muscle testing and brain imaging. These findings also improved the accuracy of genetic diagnosis for affected families.