The SUCLG1 gene helps make a protein your mitochondria use to turn food into usable energy. If this gene does not work properly, cells may not make enough energy, especially in the brain and muscles, which can lead to low muscle tone, feeding trouble, developmental delay, and raised lactic acid in the blood. In medicine, this gene is important because harmful variants can cause a rare inherited mitochondrial condition that often begins in infancy.
What is a gene?
Genes are sections of DNA that provide cells with instructions they can use to make molecules or regulate processes in the body. Some genes hold the information needed to produce proteins, the parts of cells that do the work. Others mainly control when certain processes happen, where they take place, and how strongly they run. Together, genes affect how the body develops and functions, and they can influence how you respond to food, stress, or medications. You can find more on this topic in the LearnHub.
Overview
SUCLG1Gene function
What if the gene works
The SUCLG1 gene helps mitochondria, your cells’ energy centers, turn food into usable energy. It supports a step in the Krebs cycle, which helps cells make and manage energy.
Risk
What if the gene does not work
More disruptive variants in the SUCLG1 gene can cause a mitochondrial condition that often affects the brain and muscles, leading to low muscle tone, developmental delay, and acid buildup. Milder variants may lead to later onset or less severe features.
Treatment
What does that mean for your treatment
For people with a pathogenic or loss of function variant in the SUCLG1 gene, no SUCLG1-specific treatment or drug selection approach is currently established. Care is supportive and based on the person’s symptoms, while targeted therapies for SUCLG1-related mitochondrial disease remain under study.
Conditions associated with SUCLG1
Gene function
What if the gene works
Your cells need a steady supply of energy for movement, thinking, and basic organ function. Inside mitochondria, the parts of cells that make energy, the SUCLG1 gene helps carry out a key step in the citric acid cycle. This supports normal energy production in your cells every day.
The SUCLG1 gene provides a core piece of an enzyme used in mitochondria. It joins with a partner protein so this energy step can run normally.
Inside mitochondria, the SUCLG1 gene helps change succinyl-CoA (a molecule used while processing fuel) into succinate during the citric acid cycle. This is one way your body turns nutrients from food into usable energy.
During this step, cells can store a small amount of energy as ATP or GTP, two molecules that carry usable energy. This supports steady energy production in your cells.
What is a variant?
Within a gene, a genetic variant is a slight difference in its DNA sequence. These differences are common and help shape normal human diversity, including differences in appearance, metabolism, and the way the body responds to environmental influences. Many have no noticeable effect and are simply part of 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
Variants in the SUCLG1 gene can make the protein unstable, reduce its activity, or prevent it from joining correctly with its partner proteins inside mitochondria, the cell’s energy-making parts. In explaining how SUCLG1 gene variants affect protein function, milder changes may leave some activity, while more disruptive variants can cause very little or none and can also disturb mitochondrial DNA upkeep. This range often influences how early SUCLG1-related mitochondrial disease begins and how severe it becomes.
How variants are linked to conditions
Pathogenic variants in both copies of the SUCLG1 gene cause SUCLG1-related mitochondrial DNA depletion syndrome, often described as an encephalomyopathic condition with methylmalonic aciduria. This rare inherited condition usually begins in infancy or early childhood and may involve low muscle tone, developmental delay, hearing loss, and problems with movement or breathing. Some people with SUCLG1 gene variants have a milder course, but the diagnosis itself is well established in medical genetics.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are found commonly in the general population. Most do not have a direct effect on health and simply reflect 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 also contribute. In some situations, though, 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 SUCLG1-related disease, risk is mainly determined by inheriting harmful changes in both copies of the SUCLG1 gene, usually one from each parent. In families with known SUCLG1 changes, having two carrier parents, a previous affected child, or parents who are related by blood can increase the chance in a future pregnancy.
Inheritance of SUCLG1 variants
SUCLG1-related conditions are inherited in an autosomal recessive pattern. This means a child is affected when they inherit two disease-causing SUCLG1 variants, one from each parent. Parents who each carry one SUCLG1 variant are usually unaffected carriers, and with each pregnancy there is a 25% chance of having an affected child, a 50% chance of having a carrier child, and a 25% chance of having a child with neither variant. Sons and daughters are affected equally because the SUCLG1 gene is not on a sex chromosome.
What does my SUCLG1 result mean for my family?
For families with a disease-causing change in the SUCLG1 gene, parents are usually healthy carriers, and brothers and sisters may also be carriers or may be affected. Close relatives may want to learn whether the same gene change runs in the family, especially when there is a history of early serious muscle, brain, or growth problems. Children of someone with a SUCLG1-related condition will usually be carriers unless the other parent also carries a SUCLG1 change.
Genetic information
Genetic testing
How you find out about variants
To find variants in the SUCLG1 gene, doctors use genetic testing on a blood sample, saliva, or a cheek swab. SUCLG1 genetic testing reads the gene's DNA code to look for changes that may help explain symptoms or confirm a suspected inherited mitochondrial condition. Results are interpreted alongside symptoms and family history.
When should I consider getting a genetic test?
Genetic testing for the SUCLG1 gene may be considered when a baby or child has signs of a rare inherited problem with the body’s energy supply, such as severe low muscle tone, developmental delay, feeding problems, hearing loss, or repeated high acid levels on blood tests. It can also help clarify risk when a close family member has a known SUCLG1 variant.
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 on the specific type of variant. How the body functions over time is also shaped by many other factors, including lifestyle, environment, age, and medical history. In some conditions, especially those affected by many genes, genetic information provides context rather than certainty and is best considered together with 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 put individual experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Some people break down a drug more slowly or more quickly, which can change how much of the medicine reaches the body and brain over time. These differences are common and can influence how well a treatment works or how sensitive someone is to side effects.
What is Pharmacogenetics?
Pharmacogenetics looks at how differences in genes can shape a person’s response to medicines. It examines links between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medications, genes can affect both how strongly a drug works and how the body processes it. This information can support treatment choices that are more informed and more individualized. More detail on this topic is available in the LearnHub.
Drugs influenced by the SUCLG1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how people respond to medicines, so questions about medications, side effects, or possible interactions are best discussed with your doctor or pharmacist. Seek medical advice promptly if a new medicine seems to make symptoms worse or causes unexpected problems.