The SDHB gene helps cells turn food into energy inside mitochondria, the cell’s power plants. This gene plays an important role in steady energy production, and if it does not work properly, cells may grow in abnormal ways that raise the chance of tumors, especially paragangliomas and pheochromocytomas. Disease-causing variants in the SDHB gene are also linked to some kidney cancers and gastrointestinal stromal tumors. Many people learn about SDHB through family testing after one of these tumors is found.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or direct processes in the body. Some genes hold the information needed to produce proteins, the cell parts that do much of the work. Other genes mainly regulate when certain processes occur, where they occur, and how strongly they operate. Together, genes affect how the body develops and works, and they can also shape how you respond to food, stress, or medications. For a more detailed look at this topic, you can learn more in the LearnHub.
Overview
SDHBGene function
What if the gene works
The SDHB gene helps cells turn food into energy inside mitochondria, the cell’s power centers. It also helps process succinate, a natural cell chemical, as part of routine energy metabolism.
Risk
What if the gene does not work
Variants in the SDHB gene can cause paraganglioma pheochromocytoma syndrome, with paragangliomas or pheochromocytomas and, less often, kidney cancer or digestive tract tumors. Milder and more severe variants can affect when tumors appear and which types develop.
Treatment
What does that mean for your treatment
No treatment or drug choice specific to a pathogenic variant in the SDHB gene is currently established in clinical guidelines. Tumors with loss of SDHB are being studied as biomarkers for targeted treatments, but these approaches remain investigational.
Conditions associated with SDHB
Gene function
What if the gene works
Every cell needs a steady way to turn nutrients and oxygen into usable energy. The SDHB gene supports this everyday work inside mitochondria, the parts of cells that make most of your energy. This helps explain the SDHB gene's role in cell energy production across the body.
The SDHB gene helps cells process a fuel piece called succinate during normal energy production. This is one of the routine steps your body uses to turn nutrients from food into usable energy.
Inside mitochondria (the parts of cells that make energy), this gene helps move electrons through a larger protein team. That flow supports the later steps cells use to capture energy in a usable form.
One of the SDHB gene's main roles is connecting fuel breakdown with the cell's energy making chain. By linking these two steps, it supports steady energy production in many tissues.
What is a variant?
A gene variant is a small difference in the DNA sequence within a gene. These differences are common and are part of normal human diversity, such as variation in appearance, metabolism, or the way the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. In some situations, 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
SDHB gene variants often make the SDHB protein unstable or keep it from fitting into an enzyme complex in mitochondria, the parts of cells that handle energy. More disruptive variants can sharply reduce activity or stop it altogether, while milder variants may leave some function in place; this helps explain differences in SDHB gene variant effects, including how early SDHB-related tumors may appear and how strongly the condition shows up in some families.
How variants are linked to conditions
Pathogenic variants in the SDHB gene cause hereditary paraganglioma-pheochromocytoma syndrome. SDHB gene variants are linked to pheochromocytoma and paraganglioma, and less often to kidney cancer or certain gastrointestinal stromal tumors. These tumors can appear at different ages, and people in the same family may not all have the same pattern.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are common across the general population. Most have no direct impact 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 more than one gene 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?
Risk is mostly tied to having a harmful SDHB variant, and family history may also affect how likely related tumors are to develop. There is not yet broadly confirmed evidence that diet, exercise, or other lifestyle factors clearly change this risk, so regular monitoring matters most.
Inheritance of SDHB variants
The inheritance pattern for SDHB-related conditions can differ depending on the condition involved. For the hereditary tumor syndrome linked to the SDHB gene, variants are usually inherited in an autosomal dominant way, which means a parent with the variant can pass it to a son or daughter with a 50% chance in each pregnancy. A different, much rarer condition linked to having changes in both copies of the SDHB gene follows an autosomal recessive pattern, so a child would need to inherit one altered copy from each parent. This is the key point in understanding how SDHB variants are inherited in families.
What does my SDHB result mean for my family?
For the main SDHB-related condition, a result can matter for close relatives because parents, brothers, sisters, and children may also carry the same gene change and may want to discuss testing. SDHB is also linked to a much rarer condition that follows a different family pattern, so what it means for relatives depends on which SDHB-related condition matches the result. In some families, an SDHB change starts new in one person, so it is not always inherited from a parent.
Genetic information
Genetic testing
How you find out about variants
An SDHB genetic test uses a blood or saliva sample to look for variants in the SDHB gene. This is how doctors find out about SDHB variants, either by checking for a known family variant or by reading the gene on an inherited cancer panel. Results may show a pathogenic variant, no variant, or an uncertain result.
When should I consider getting a genetic test?
Consider SDHB genetic testing if you or close relatives have had certain rare nerve or adrenal gland tumors, called paragangliomas or pheochromocytomas, especially at a young age or more than once. Testing can also help if a family member has a known SDHB gene change or there is a family pattern of certain kidney cancers.
A genetic result is only one part of your health story
A genetic result can be informative, but what it tells you varies by the condition and by the type of variant involved. Many factors, including lifestyle, environment, age, and medical history, shape how the body works over time. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is most useful when viewed alongside other parts of care. In other situations, a genetic result may 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, moves it through the body, or responds to it at its target. This helps explain why the same medication may work well for one person, have less effect in another, or cause more side effects in someone else. These differences are common and are one reason treatment response can vary from person to person.
What is Pharmacogenetics?
Pharmacogenetics explores how genetic differences can affect the way a person responds to medication. It examines relationships between genes and drugs to help explain why the same treatment can work differently from one person to another. For many medicines, genes influence either how strongly a drug works or how the body processes it. This information can support treatment decisions that are more informed and more personalized. To learn more about this topic, more information is available in the LearnHub.
Drugs influenced by the SDHB gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication response, so general health concerns, treatment questions, or side effects are best discussed with your doctor.
History
Families and communities once noticed rare patterns of paraganglioma and related tumors appearing in several relatives, long before the cause was known. In the late 20th century, researchers began tracing these family patterns to inherited gene changes. From these first observations, research expanded steadily. In 2001, variants in the SDHB gene were identified as one cause of hereditary paraganglioma, marking an important step in cancer genetics. This discovery helped connect a long-recognized family syndrome with a specific gene and changed how affected families were evaluated. Over time, the way this gene was viewed shifted as studies showed that SDHB-related inherited risk could involve different tumor types and different ages within the same family.