Your cells depend on the SDHAF2 gene to help switch on part of the system they use to make energy. If this gene does not work properly, that energy pathway may falter, and some people develop inherited paraganglioma, with tumors that usually grow slowly near nerves in the head and neck. These tumors may cause a neck lump, ringing in the ears, hearing changes, or symptoms from hormone release, although some people have no symptoms at first. Pathogenic variants in the SDHAF2 gene are rare but can run in families.
What is a gene?
Within DNA, a gene is a stretch that carries instructions your cells use to make molecules or regulate processes in the body. Some genes provide the information needed to make proteins, the parts of cells that do much of the work. Others mainly help control when certain processes happen, where they happen, and how strongly they run. Taken 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 detail on this topic in LearnHub.
Overview
SDHAF2Gene function
What if the gene works
The SDHAF2 gene helps your cells build a working part of mitochondria, the structures that make energy. This supports normal energy production.
Risk
What if the gene does not work
If the SDHAF2 gene does not work correctly, it can cause hereditary paraganglioma, usually with one or more head and neck paragangliomas. Effects can range from milder to more pronounced, influencing age of onset and whether one or several tumors develop.
Treatment
What does that mean for your treatment
A pathogenic variant in the SDHAF2 gene does not currently change treatment in a gene specific way; care is based on the tumor and its location. SDH deficient tumors linked to the SDHAF2 gene are being studied as a distinct group for newer targeted treatments, but this has not led to an established SDHAF2 specific drug approach.
Conditions associated with SDHAF2
Gene function
What if the gene works
Your cells need the SDHAF2 gene to help set up a key enzyme inside mitochondria, the parts of cells that make energy. This support lets that enzyme join the normal process of turning fuel from food into usable energy. Understanding how the SDHAF2 gene helps mitochondria make energy gives useful context for its role across many tissues.
The SDHAF2 gene helps place a vitamin-like helper called FAD onto the SDHA protein. This step prepares the succinate dehydrogenase enzyme for its normal energy related work.
By helping build working complex II, this gene supports a step in the mitochondrial energy chain. That helps cells move energy from food through the system that powers routine cell activity.
This gene supports an enzyme that connects the citric acid cycle, which breaks down fuel, with the cell’s energy chain. That link helps keep energy production coordinated and steady.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These differences are common and are part of normal human diversity, including variation in appearance, metabolism, and how the body responds to environmental influences. Many variants do not cause any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can change how a gene functions more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
In discussions of how SDHAF2 gene variants affect protein function, some DNA changes make the helper protein unstable or stop it from attaching properly to SDHA. That can leave the cell's complex II enzyme partly assembled or much less active. Milder variants may only reduce this step, while more severe variants can largely shut it down. Bigger functional losses are the changes most often linked to paraganglioma in families carrying disease-causing variants in the SDHAF2 gene.
How variants are linked to conditions
Pathogenic variants in the SDHAF2 gene cause hereditary paraganglioma type 2, a rare inherited condition most often linked to head and neck paragangliomas. The SDHAF2 gene and hereditary paraganglioma connection is strongest when the variant is inherited from the father. These tumors are often noncancerous, but some people develop more than one over time.
A variant is not necessarily a diagnosis
Genetic variants are common in the general population and are a normal part 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 indicates a possible link rather than a definite diagnosis, especially when multiple genes and environmental factors are involved. In some cases, 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 SDHAF2, risk is mainly set by whether a disease-causing change is inherited and which parent it comes from. People who inherit the change from their father have a much higher chance of developing paragangliomas, while inheritance from the mother is much less likely to lead to the condition.
Inheritance of SDHAF2 variants
Variants in the SDHAF2 gene are usually inherited in an autosomal dominant pattern, but the SDHAF2 inheritance pattern has an important parent of origin effect. A child can inherit the variant from either parent, yet people usually develop SDHAF2-related paraganglioma only when the variant is passed down from their father. If a parent carries the variant, each child has a 50% chance of inheriting it. A variant inherited from the mother is usually silent in the child, although that child can still pass it on to the next generation.
What does my SDHAF2 result mean for my family?
A harmful change in the SDHAF2 gene can run in families in a dominant way, so close relatives may also carry the same change. For many families, the key detail is that health effects are mainly seen when the changed gene is inherited from the father, while people who inherit it from their mother may carry it without developing the condition. Because of that, the meaning for relatives depends on which side of the family the result came from.
Genetic information
Genetic testing
How you find out about variants
To look for changes in the SDHAF2 gene, labs use genetic testing for SDHAF2 variants on a blood or saliva sample. The test reads the DNA sequence, and some labs also check for missing or extra pieces, which can help confirm a hereditary paraganglioma diagnosis in the right clinical setting.
When should I consider getting a genetic test?
Testing for SDHAF2 may be worth discussing if you or close relatives have had paragangliomas, which are rare tumors that often develop in the head or neck. It can be especially useful when these tumors seem to run in a family, particularly through the father's side.
A genetic result is only one part of your health story
A genetic finding can provide useful insight, but how much it reveals depends on the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, influence how the body functions. For some conditions, especially those shaped by many genes, genetic information offers context rather than certainty and is most helpful when considered alongside other parts of care. In other situations, a genetic result can give a clear answer. In areas like medication response, genetic results may help put individual experiences into perspective.
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, so the same dose can lead to different effects or a different chance of side effects. This kind of variation is common and can influence how well a treatment works or how sensitive your body is to it.
What is Pharmacogenetics?
Pharmacogenetics studies the ways genetic differences shape responses to medicines. It examines links between genes and medications to better explain why the same treatment can affect people differently. For many drugs, genes influence either how strongly a medicine works or how the body handles it. This information can support treatment decisions that are better informed and more individualized. To explore this subject in greater detail, you can find more in the LearnHub.
Drugs influenced by the SDHAF2 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication response. If you have symptoms, concerns about treatment, or side effects from medicine, it is best to speak with your doctor.
History
The SDHAF2 gene entered the medical literature in 2009, when researchers studying families with inherited head and neck paragangliomas identified it as the cause of a rare form of the condition. Early reports referred to it as SDH5, and the name was later updated to the SDHAF2 gene as understanding of its role became clearer. This discovery mattered because it expanded the group of genes linked to hereditary paraganglioma and helped explain why some families had a clear inherited pattern despite negative results in other known genes. From these first observations, research expanded steadily. Another important milestone was the recognition that disease risk in these families followed an unusual parent of origin pattern, which drew wide interest in cancer genetics.