The SDHA gene helps cells turn food into energy inside mitochondria, the parts of the cell that act like power plants. If it does not work properly, some tissues may not get the energy they need, which can lead to muscle weakness, developmental or nerve-related problems, or heart symptoms. In medicine, this gene is important because certain inherited SDHA variants are also linked to a higher chance of paraganglioma, pheochromocytoma, and some stomach or kidney tumors. Many people with an SDHA variant stay well, but the effects depend on the specific variant.
What is a gene?
A gene is a stretch of DNA that carries instructions your cells use to make molecules or direct processes in the body. Some genes hold the information needed to produce proteins, the parts of cells that do much of the work. Other genes mainly regulate when certain processes take place, where they occur, 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. If you want to explore this subject in more detail, you can find more in the LearnHub.
Overview
SDHAGene function
What if the gene works
The SDHA gene helps your cells make energy, especially in organs with high energy needs like the brain and muscles. Its protein is part of an enzyme in mitochondria, the cell's energy centers, that helps turn food into usable energy.
Risk
What if the gene does not work
Variants in the SDHA gene can range from milder to more severe, which may shape whether effects are mainly a higher tumor risk or an earlier-onset mitochondrial disease affecting the brain, muscles, or heart. Tumor risk is linked to paraganglioma, pheochromocytoma, and some SDH-deficient stomach tumors.
Treatment
What does that mean for your treatment
No SDHA-specific treatment or drug choice is currently established in clinical guidelines. SDHA-related tumors are being studied as a biomarker group for treatments that target altered cell metabolism and, in some settings, immune checkpoint drugs.
Conditions associated with SDHA
Gene function
What if the gene works
Your cells need a steady supply of energy for everyday tasks like muscle movement, heartbeats, and brain activity. The SDHA gene helps mitochondria, the parts of cells that release energy from food, keep that process moving. It supports central energy reactions that let cells make usable fuel.
In mitochondria, SDHA carries out a key step in the cell’s main energy cycle. This helps cells release energy from nutrients.
SDHA passes electrons, small energy carrying particles, into the respiratory chain in mitochondria. This is one part of how cells make energy from food and oxygen.
SDHA connects the energy cycle with the respiratory chain so both systems work together smoothly. This supports steady energy needs across many tissues.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and are part of normal human diversity, including differences in appearance, metabolism, and the way the body responds to environmental influences. Many variants do not produce any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can more substantially change how a gene works and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the SDHA gene can reduce or shut down the SDHA protein’s activity in mitochondrial complex II, often by making the protein unstable, misshapen, or unable to work with nearby partner proteins. Some SDHA gene variants leave partial activity, while more disruptive variants can result in little or no function. This range in effect can influence how much cell energy production is disturbed and, in established SDHA related conditions, may affect when features begin and how marked they are.
How variants are linked to conditions
Doctors recognize SDHA gene variants linked to paraganglioma and pheochromocytoma, and some are also associated with gastrointestinal stromal tumors. These variants can raise tumor risk, but they do not mean a tumor will definitely develop. When both copies of the SDHA gene carry pathogenic variants, they can cause mitochondrial complex II deficiency, an inherited condition that may lead to developmental delay, low muscle tone, seizures, or heart problems.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widespread in the general population. Most do not have a direct effect on health and instead reflect normal 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 are involved. 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?
There is not yet broadly confirmed evidence on specific factors that clearly increase or reduce health risks linked to the SDHA gene. Risk can vary by the exact gene change and family history, and anyone concerned about their personal risk should speak with a doctor or genetic counselor.
Inheritance of SDHA variants
The inheritance pattern for SDHA-related conditions can differ depending on the health issue involved. For tumor predisposition linked to the SDHA gene, inheritance is usually autosomal dominant, which means a parent carrying the variant can pass it to each child with a 50% chance. For some rare energy production conditions caused by the SDHA gene, inheritance is autosomal recessive, meaning a child usually inherits one nonworking copy from each parent. This is why SDHA inheritance is best understood in the context of the specific condition being considered.
What does my SDHA result mean for my family?
For many living with an SDHA finding, what it means for family depends on which SDHA-related condition the result is linked to. Some SDHA changes are tied to an inherited tumor risk that can run in families, so close relatives may also carry the same change and may choose to discuss testing. Other SDHA changes cause a condition only when both copies of the gene are changed, which can mean relatives are healthy carriers.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for SDHA variants uses a blood or saliva sample to read the SDHA gene and check for spelling changes or missing pieces of DNA. Results may show a harmful variant, a harmless variant, or a variant of uncertain significance, which means the lab has not confirmed its health effect.
When should I consider getting a genetic test?
Consider SDHA genetic testing if you or close relatives have had paraganglioma or pheochromocytoma, rare growths linked to nerve or adrenal tissue. It can also matter after certain stomach or intestinal tumors, because a harmful SDHA change can help explain the cause and whether it may run in families.
A genetic result is only one part of your health story
A genetic result can be informative, but how much it explains varies by the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, also shape how the body functions. For some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is most useful when considered together with 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 personal experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can influence how your body responds to medicines. Small DNA differences can affect how a drug is taken up, broken down, or how strongly it works in the body. This helps explain why the same treatment may work well for one person, seem less effective for another, or cause more side effects in someone else. These differences are common and are just one part of the picture, along with age, overall health, and other medicines.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape a person’s response to medication. It focuses on links between genes and drugs to help explain why the same treatment may work differently from one person to another. With many medications, genes can affect how strongly a drug works or how the body handles it. This information can support more informed and more individualized treatment decisions. More on this topic is available in the LearnHub.
Drugs influenced by the SDHA 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 any concerns about side effects, new symptoms, or medication changes are best discussed with your doctor.
History
Since the earliest days of medicine, efforts have been made to understand inherited patterns. The SDHA gene entered genetics through decades of work on succinate dehydrogenase, an enzyme complex studied as scientists mapped how cells make energy in the 20th century. Building on this early work, researchers later identified the individual genes behind that complex, including the SDHA gene. In the 2000s, inherited SDHA variants became recognized as a cause of some paragangliomas, pheochromocytomas, and a small number of gastrointestinal stromal tumors. Over time, descriptions became more precise as genetic testing linked SDHA to a broader range of inherited tumor risk patterns. These historical steps shaped today’s understanding of SDHA in both rare inherited conditions and cancer genetics.