The SCN8A gene gives your brain cells instructions for a sodium channel, a tiny doorway that helps electrical signals travel. This gene plays an important role in keeping nerve messages balanced, so disruptive variants can make signaling too active or less effective. Depending on the variant, people may have epilepsy, developmental delay, learning difficulties, low muscle tone, or movement problems. Some SCN8A related conditions begin in infancy, while others are milder and appear later in childhood.
What is a gene?
Genes are sections of DNA that carry instructions your cells use to make molecules or regulate processes in the body. Some genes hold the directions for making proteins, the parts of cells that do the work. Others mainly control when certain processes happen, where they happen, and how strongly they are carried out. Together, genes affect how the body develops and functions, and they can influence how you respond to food, stress, or medications. To go into this topic in more detail, you can learn more in LearnHub.
Overview
SCN8AGene function
What if the gene works
The SCN8A gene helps nerve cells send electrical signals. Its protein forms part of a sodium channel that supports brain and nerve communication, especially when signals start and travel along nerves.
Risk
What if the gene does not work
Variants in the SCN8A gene can cause epilepsy, often beginning in infancy or childhood, with a range from milder seizures to severe developmental and epileptic encephalopathy. Some people also have movement problems or developmental delay, depending on the variant’s effect.
Treatment
What does that mean for your treatment
No SCN8A-specific treatment or management approach is currently established in clinical guidelines. The SCN8A gene is an active drug target in epilepsy research, and selective Nav1.6 blockers are being studied, mainly for SCN8A-related seizures linked to increased channel activity.
Conditions associated with SCN8A
Gene function
What if the gene works
The SCN8A gene helps nerve cells send fast, precise electrical messages. In everyday terms, it helps brain cells send signals that support movement, sensation, attention, and other routine functions. Its protein forms part of a sodium channel, a tiny gateway that opens at the right moment to let a charged mineral enter the cell.
Its protein forms a sodium channel, a gate in the cell surface that opens briefly at the right time. This lets sodium move into the nerve cell and starts the electrical change needed for signaling.
Many of these channels gather at the part of a nerve cell where messages begin. This helps launch clear electrical impulses with the timing needed for fast communication.
SCN8A channels also sit at points along nerve fibers that boost a message as it travels. This supports smooth, efficient signaling over longer distances in the brain and nerves.
The channel can reopen in a controlled way so some nerve cells can fire repeatedly when needed. That steady timing helps networks coordinate tasks such as movement, focus, and sensation.
What is a variant?
A genetic variant is a slight change in the DNA sequence of a gene. These changes are common and help account for normal human diversity, including differences in appearance, metabolism, or the way the body responds to environmental influences. Many variants do not cause any noticeable effect and are simply part of natural genetic variation. Sometimes, 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
Variants in the SCN8A gene can affect function by making the nerve cell channel too active, less active, unstable, or unable to reach the cell surface. Some changes keep the channel open longer and let brain cells fire too easily, while others reduce or stop channel activity. Effects range from milder variants with partial function to more severe variants that disrupt protein production, which can influence how early symptoms begin and how marked they are.
How variants are linked to conditions
Pathogenic variants in the SCN8A gene can cause SCN8A-related developmental and epileptic encephalopathy, a condition marked by seizures that often begin in infancy or childhood and may occur with developmental delay. Some people with variants in the SCN8A gene have intellectual disability or movement problems, with or without frequent seizures. The exact features vary by variant, so the same gene change does not affect everyone in the same way.
A variant is not necessarily a diagnosis
Across the general population, genetic variants are common and are a normal feature of human biology. Most do not directly affect 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 also play a role. There are exceptions, though: in some cases, one well-characterized variant in a particular gene is 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 SCN8A gene itself. For many living with a disease-causing SCN8A change, risk is driven mainly by the variant, while things like fever, missed seizure medicine, sleep loss, or flashing lights can trigger seizures in some people and raise the chance of complications.
Inheritance of SCN8A variants
SCN8A-related conditions are usually inherited in an autosomal dominant pattern, which means one altered copy of the SCN8A gene can be enough to cause the condition. If a parent carries a disease-causing SCN8A variant, each child has a 50% chance of inheriting it. In many families, though, the variant is new in the child and was not inherited from either parent. This means how SCN8A variants are inherited can involve either transmission from an affected parent or a new change arising for the first time.
What does my SCN8A result mean for my family?
For many living with an SCN8A-related condition, the gene change is inherited in a dominant way, so close relatives such as parents, brothers, sisters, and children may also carry it and could have symptoms or a higher chance of having an affected child. In many families, the change happened new in the child and was not inherited from either parent. Because of that, what an SCN8A result means for relatives depends on whether the change was passed down or started for the first time in one family member.
Genetic information
Genetic testing
How you find out about variants
SCN8A genetic testing looks for variants in the SCN8A gene using a blood sample or cheek swab. Labs read the gene's DNA, often as part of an epilepsy panel or broader sequencing test, to see whether a variant may help explain seizures or related symptoms. Results are reviewed alongside medical history because not every variant is disease-causing.
When should I consider getting a genetic test?
Genetic testing for the SCN8A gene may be worth considering if someone has unexplained seizures, especially seizures that start in infancy or early childhood, with developmental delays or movement problems. It can also be helpful when similar symptoms run in the family.
A genetic result is only one part of your health story
A genetic result can provide valuable insight, but how much it reveals varies with the condition and the type of variant involved. Over time, factors such as age, lifestyle, environment, 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 best understood together with other parts of care. In other situations, a genetic result can offer a clear answer. In areas such as medication response, genetic results can also help make sense of individual experiences.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines, so the same treatment may work well for one person but less well for another. Some gene changes influence how quickly a drug is broken down, how strongly it acts on its target, or how sensitive the body is to side effects. This kind of variation is common and can help explain differences in benefit, unwanted effects, and how long a medicine stays active in the body.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect the way medications work. By studying links between genes and specific drugs, it helps explain why the same treatment can have different effects from one person to another. For many medicines, genes influence how the body handles a drug and how strong its effects are. This information can support more personalized and well-informed treatment choices. More detail on this subject is available in the LearnHub.
Drugs influenced by the SCN8A gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting medication response, so it is best to talk with your doctor before starting, stopping, or changing any medicine, especially seizure treatment. SCN8A has been studied in epilepsy because some gene changes may affect how well certain seizure medicines work, but this is not yet used as routine prescribing guidance.
History
The SCN8A gene entered medical genetics more recently than some better known epilepsy genes, as researchers linked it to severe seizure conditions in the early 2010s. From these first observations, research expanded steadily, and SCN8A became recognized as an important cause of developmental and epileptic encephalopathy in some children. Scientific classifications changed as researchers learned more about the gene, especially as doctors saw that different SCN8A variants could be tied to different symptom patterns. As genetic testing became more widely used, more families received a clearer explanation for seizures, developmental differences, or movement problems that had previously gone unexplained. This growing knowledge has helped shape today’s understanding of SCN8A related conditions and their place within epilepsy genetics.