The SDHD gene helps cells make energy in mitochondria, the parts of the cell that supply power. If this gene does not work properly, cells can behave as if oxygen is low and may form paragangliomas or pheochromocytomas, which are tumors in nerve tissue. Inherited pathogenic variants in the SDHD gene are linked to a hereditary tumor syndrome, often affecting the head and neck. This gene is mainly known in medical genetics rather than popular culture.
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 provide the directions for making proteins, the working parts of cells. Others mainly help determine when certain processes occur, where they happen, and how strongly they run. Taken together, genes influence how the body develops and functions, and they can 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
SDHDGene function
What if the gene works
The SDHD gene helps mitochondria, your cells’ energy centers, turn food into usable energy. It forms part of complex II, linking two key steps in energy production and supporting steady cell function.
Risk
What if the gene does not work
Pathogenic variants in the SDHD gene are best known for raising the chance of paragangliomas, especially in the head and neck, and sometimes pheochromocytomas. Milder and more severe variants can influence which tumors develop and when they appear.
Treatment
What does that mean for your treatment
A pathogenic or loss-of-function variant in the SDHD gene does not currently have a standard SDHD-specific treatment or drug choice. Care is usually guided by the tumor’s location, hormone release, growth, and spread, using options such as surgery, radiation, or other cancer treatments when needed. SDH-deficient tumors are being studied as a biomarker-defined group for targeted therapies, but no SDHD-directed treatment is yet established.
Conditions associated with SDHD
Gene function
What if the gene works
Your cells use the SDHD gene to support how they make energy from food. It works inside mitochondria, the parts of cells that act like power stations. This is a core part of how the SDHD gene helps your cells make energy for routine body functions.
Inside mitochondria, the SDHD gene helps cells take a key step in getting energy out of food. This supports steady ATP production, the main form of usable energy in your cells.
Its protein is part of complex II, a protein group that passes electrical charges through the cell's energy system. This helps connect food breakdown to the next stages of energy production.
The SDHD gene helps keep complex II positioned in the inner membrane of mitochondria, where this work takes place. This allows the different parts of the complex to work together efficiently.
What is a variant?
A genetic variant is a minor change in a gene’s DNA sequence. These changes are common and help shape normal human diversity, such as differences in appearance, metabolism, or the way the body reacts to environmental influences. Many do not cause any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can affect how a gene works more strongly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the SDHD gene can change the SDHD protein’s shape or stability, so the cell has trouble building a working mitochondrial complex II. In plain terms, this is how SDHD gene variants affect cells: milder variants may leave some activity, while more disruptive variants can sharply reduce or stop electron transfer and lead to succinate buildup, which can make cells behave as if oxygen were low.
How variants are linked to conditions
Pathogenic variants in the SDHD gene cause hereditary paraganglioma-pheochromocytoma syndrome, most often linked to paragangliomas in the head and neck and sometimes to pheochromocytomas. Some people also develop paragangliomas in the chest, abdomen, or pelvis. In families, SDHD gene variants linked to hereditary paraganglioma and pheochromocytoma syndrome usually have the clearest health impact when the variant is inherited from the father.
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 are involved. In some situations, though, one well-characterized variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For people with an SDHD gene change, risk is shaped most by which parent it came from. These tumors usually develop when the change is inherited from the father, while the chance is much lower when it is inherited from the mother. Risk also tends to rise with age, so ongoing checkups can matter.
Inheritance of SDHD variants
For families asking how the SDHD gene is inherited, the main pattern is autosomal dominant, which means a child can inherit the variant from either parent. In practice, SDHD related paraganglioma and pheochromocytoma risk shows a parent of origin effect: the condition is usually seen when the variant is inherited from the father. If you inherit the variant from your mother, you can still pass it on, but you often do not develop the condition yourself. Each child of a parent carrying the variant has a 50% chance of inheriting it.
What does my SDHD result mean for my family?
For many living with an SDHD change, close relatives can also carry it, so parents, brothers, sisters, and children may share the same result. Family impact depends on which parent passed it on: SDHD-related illness usually develops when the changed gene is inherited from the father, while people who inherit it from the mother often remain healthy carriers but can still pass it to their children. This means the pattern in a family can look uneven across generations.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for SDHD variants usually uses a blood or saliva sample to read the SDHD gene and look for changes in its DNA sequence, sometimes along with missing or extra pieces. Results can show whether a variant is present, absent, or uncertain, which helps clarify inherited risk in a family.
When should I consider getting a genetic test?
Consider SDHD genetic testing if you or close relatives have had paraganglioma or pheochromocytoma, which are rare growths linked to nerve tissue and the adrenal glands. Testing can also make sense when several family members have these growths or when a known SDHD variant runs in the family.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it reveals depends on the condition and on the type of variant involved. Over time, how the body works is shaped by many factors, including lifestyle, environment, age, and medical history. In some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is best understood 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. Small differences in genes can change how the body breaks down, moves, or reacts to a drug, so the same treatment may work better for one person and cause more side effects in another. This kind of variation is common and helps explain why medication response can differ from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can affect the way a person responds to medication. It studies connections 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 processes it. This information can help support treatment decisions that are more informed and more individualized. You can read more about this topic in the LearnHub.
Drugs influenced by the SDHD gene
When should I seek medical advice?
There is no broadly confirmed role for this gene in day-to-day medication decisions, so questions about side effects, drug interactions, or changes in treatment are best discussed with your doctor or pharmacist.
History
The SDHD gene entered medical history in the early 2000s, when researchers found that inherited variants in this gene could cause some family cases of paraganglioma, a rare tumor that often grows near nerves and blood vessels. This discovery helped solve a long-standing mystery in families where these tumors appeared across generations. Building on this early work, scientists also recognized an unusual inheritance pattern: risk is typically linked to a variant passed down from the father. That finding drew wide interest because it was different from the usual way many inherited conditions are tracked in families. Over time, SDHD became an important part of the broader story of hereditary tumor syndromes and genetic testing for inherited cancer risk.