The SDHAF1 gene helps assemble part of the cell’s energy making machinery in mitochondria, and if it does not work properly, some cells may not make enough energy. This gene plays an important role in tissues with high energy needs, especially the brain and muscles. People with harmful variants in the SDHAF1 gene can develop a rare inherited mitochondrial condition, often in childhood, with low muscle tone, weakness, movement difficulties, developmental delay, and changes in brain white matter.
What is a gene?
A gene is a stretch of DNA that holds instructions your cells use to make molecules or manage activities in the body. Some genes provide the code for proteins, which are the parts of cells that do much of the work. Other genes are used mainly to regulate when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can also influence how you react to food, stress, or medicines. For a more detailed look at this topic, you can read more in the LearnHub.
Overview
SDHAF1Gene function
What if the gene works
The SDHAF1 gene helps your cells assemble part of the machinery in mitochondria, the structures that make energy. This supports steady energy production, especially in muscles and the nervous system.
Risk
What if the gene does not work
Pathogenic variants in the SDHAF1 gene can cause a mitochondrial condition, often in infancy or childhood, with muscle weakness, developmental slowing, and white matter changes in the brain. Effects can range from milder to more severe depending on the variant.
Treatment
What does that mean for your treatment
No treatment or medication choice specific to pathogenic variants in the SDHAF1 gene is currently established.
Conditions associated with SDHAF1
Gene function
What if the gene works
Your cells need the SDHAF1 gene to help a key energy enzyme in mitochondria, the parts of cells that make usable energy, get ready for work. This support is part of how the SDHAF1 gene helps cells make energy from food. It helps keep everyday cell activity running smoothly.
The SDHAF1 gene helps assemble succinate dehydrogenase, an enzyme also called complex II. It supports the stage where this enzyme becomes properly prepared for work inside mitochondria.
Its protein helps place iron-sulfur clusters, tiny mineral-based parts, into the SDHB section of complex II. These parts allow the enzyme to pass along electrons during energy production.
By helping complex II work normally, the SDHAF1 gene supports a key step in the cell’s energy system. This helps cells turn nutrients into usable energy in a steady way.
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 differences between people, such as appearance, metabolism, or the way the body responds to environmental influences. Many variants do not have any noticeable effect and are simply part of natural genetic variation. At times, though, a variant changes how a gene works more significantly and may contribute to or lead to a genetic condition.
Genetic variants
What if the gene does not work
Variants in the SDHAF1 gene can make its helper protein unstable or less able to support assembly of mitochondrial complex II, one of the systems that help cells make energy. This explains how variants in the SDHAF1 gene affect mitochondrial complex II: milder variants may leave some activity, while more severe variants can cause a marked drop in complex II function and, in some people, earlier or more pronounced signs of mitochondrial complex II deficiency.
How variants are linked to conditions
Pathogenic variants in the SDHAF1 gene cause mitochondrial complex II deficiency, nuclear type 2, a rare inherited mitochondrial condition. People carrying a disease-causing SDHAF1 variant may develop developmental delay or loss of skills, muscle weakness, movement problems, and brain white matter changes called leukoencephalopathy. This is the main well-established condition linked to the SDHAF1 gene.
A variant is not necessarily a diagnosis
Genetic variants are a usual part of human biology and are widespread in the general population. Most do not directly affect health and instead 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 play a role. In some situations, though, a single well characterized variant in a particular 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 increase or reduce health risk related to the SDHAF1 gene. In families with an SDHAF1-related condition, risk is mainly shaped by the genetic change itself rather than lifestyle, and a doctor or genetic counselor can help explain personal and family risk.
Inheritance of SDHAF1 variants
SDHAF1-related conditions follow an autosomal recessive inheritance pattern, which is the key point in understanding how SDHAF1 gene variants are inherited in families. This means a person usually needs to inherit two disease-causing variants in the SDHAF1 gene, one from each parent, to be affected. Parents who each carry one variant are typically unaffected carriers. With each pregnancy, two carrier parents have a 25% chance of having an affected child, a 50% chance of having a child who is a carrier, and a 25% chance of having a child with neither familial variant.
What does my SDHAF1 result mean for my family?
For SDHAF1, family impact is usually discussed in the setting of a recessive condition. This often means parents are healthy carriers, and brothers or sisters may also be carriers or, less often, also be affected. Close relatives may want to learn whether the same gene change runs in the family, especially if there is a history of similar early neurologic illness.
Genetic information
Genetic testing
How you find out about variants
SDHAF1 genetic testing usually uses a blood sample or cheek swab. A lab reads the SDHAF1 gene as part of a mitochondrial disease panel or exome test to look for variants that may explain symptoms and show whether the condition runs in the family.
When should I consider getting a genetic test?
Consider testing for the SDHAF1 gene when a child or young person has unexplained muscle weakness, low stamina, developmental problems, or brain scan changes that suggest a rare inherited energy-production condition. It can also be useful if a close relative has a known SDHAF1 variant. Testing can help confirm the cause.
A genetic result is only one part of your health story
A genetic result can be informative, but how much it explains varies with the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, affect how the body functions. For some conditions, particularly those shaped by many genes, genetic information provides context rather than certainty and makes the most sense when considered with other parts of care. In other situations, a genetic result can give a clear answer. For medication response, genetic results can also help put personal experiences in 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 absorbs, breaks down, or uses a drug, so the same treatment may work better for one person than another or cause more side effects in some people. This kind of variation is common and is one reason medication response can differ from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines the ways genetic differences shape how people respond to medicines. It studies gene-drug relationships to clarify why the same treatment can affect one person differently than another. For many drugs, genes influence both how strongly a medicine works and how the body handles it. This information can support more personalized and better informed treatment choices. More detail on this topic is available in the LearnHub.
Drugs influenced by the SDHAF1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work or which side effects may happen. Questions about symptoms, new medicines, side effects, or supplements are best discussed with your doctor or pharmacist.