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SCN2A is a gene that plays a critical role in how the brain develops and functions. When SCN2A is altered, through a variant that makes its protein overactive or underactive, it can cause a range of serious neurological conditions, including epilepsy, developmental delay, intellectual disability, movement disorders, and autism. Severity and presentation vary widely depending on the type of variant.
SCN2A-related disorders are one of the leading known genetic causes of developmental and epileptic encephalopathy, DEE for short. DEE describes a group of conditions where seizure activity and the underlying brain difference both contribute to developmental challenges.
SCN2A, DEE, genetics, treatment, genetic testing, gene therapy, available to download free, including translations in Korean, Chinese, Hindi, and Japanese.
The term DEE replaced older terminology (such as "epileptic encephalopathy") to better reflect that the developmental impact is not caused solely by seizures, it is part of the condition itself.
In most cases, DEE has a genetic cause, a change (variant) in a specific gene that affects how the brain develops and functions. Over 100 different genes have now been linked to DEE, and new genetic causes continue to be identified through research.
Some of the more commonly identified genetic causes include:
Not every person with DEE will have a confirmed genetic cause identified. As genetic testing technology improves, more families are receiving specific diagnoses, but for some, the cause remains unknown. In a smaller number of cases, DEE may be caused by structural brain abnormalities, metabolic conditions, or immune-mediated processes rather than a genetic variant.
DEE is typically identified when a child (or, less commonly, an adult) presents with:
Diagnosis usually involves a combination of clinical assessment, electroencephalogram (EEG), brain imaging (MRI), and genetic testing. Genetic testing, through a gene panel, whole exome sequencing, or whole genome sequencing, is now recommended early in the diagnostic process for anyone presenting with DEE features.
For many families, the path to diagnosis is not straightforward. It may take multiple investigations, second opinions, and significant time before a specific genetic cause is identified. SCN2A Australia is here to help you navigate that process.
A DEE diagnosis, whether at the syndrome level or tied to a specific gene, is significant. It can bring both relief (finally having a name for what you are seeing) and grief (understanding the road ahead).
It does not define your family member's potential. People living with DEE conditions have rich, meaningful lives. The impact of a DEE condition varies enormously, and what is possible for any individual cannot be fully predicted at diagnosis.
What we know is that early support, coordinated care, connection with others who understand, and access to the latest research all make a genuine difference.
SCN2A-related disorders are one specific cause within the broader DEE family. SCN2A Australia was founded by and for families affected by SCN2A, and that deep expertise remains central to everything we do.
Over time, our work has extended to support the broader DEE community, because the challenges families face, the advocacy work needed, and the research approaches being developed have much in common across genetic causes.
Whether your family member has an SCN2A variant, a diagnosis of another DEE-related condition, or is still awaiting a specific genetic result, SCN2A Australia can help.
No two people with an SCN2A variant are affected in exactly the same way. Some experience frequent seizures from infancy; others have milder presentations with autism spectrum features and few or no seizures. Understanding where your family member sits within this spectrum, and why, is one of the things we can help you navigate.
The SCN2A gene carries the instructions for making a protein called Nav1.2, a sodium channel that plays a critical role in brain cell communication.
Nav1.2 acts like a gateway in the walls of neurons (brain cells). It controls the movement of sodium into the cell, which triggers the electrical signals that allow neurons to communicate, to "fire", and send messages across the brain and to the rest of the body.
When Nav1.2 works as it should, this electrical activity is precisely regulated. When the SCN2A gene has a pathogenic variant, Nav1.2 may not function correctly, and that balance can be disrupted.
Not all SCN2A variants cause the same type of disruption. Understanding the difference matters because it directly affects which treatments are most likely to help.
This distinction is not just theoretical. Some anti-seizure medications that help people with gain-of-function variants may worsen symptoms in those with loss-of-function variants, which is why genetic diagnosis matters so much for guiding treatment decisions.
Because SCN2A variants can cause both overactivity and underactivity of the sodium channel, the range of symptoms is broad. Common features include some or all of the following:
Seizures are the most frequently reported feature, particularly in gain-of-function variants. They may begin in the neonatal period (first 28 days) or early infancy, and can include focal, tonic, clonic, or other seizure types. Seizure severity and frequency vary significantly.
Many individuals with SCN2A variants experience some degree of developmental delay. This may affect motor development, language acquisition, cognitive development, or a combination. The degree varies widely across the SCN2A spectrum.
ASD features are particularly common in individuals with loss-of-function variants. Some individuals with SCN2A variants have a diagnosis of ASD with minimal seizure activity.
Some individuals experience movement disorders, including hypotonia (low muscle tone), ataxia, or difficulties with coordination.
Sleep problems are common across the SCN2A community and can significantly affect quality of life for the individual and their family.
Feeding difficulties, reflux, and constipation are reported by many families, particularly in individuals with more complex presentations.
SCN2A-related disorders are diagnosed through genetic testing, specifically, identification of a pathogenic or likely-pathogenic variant in the SCN2A gene. This is most commonly identified through:
Most families reach a diagnosis after a period of investigation, often following the onset of seizures or developmental concerns. For some families, diagnosis takes months or years. For others, increasingly, newborn screening or early genetic testing is accelerating diagnosis.
If your family is still awaiting a diagnosis, or if you have had a genetic result you don't fully understand, our team can help you connect with a genetic counsellor or an SCN2A-experienced clinician.
There is currently no cure for SCN2A-related disorders. Treatment is focused on managing symptoms, reducing seizure frequency, and supporting development and quality of life.
Medication selection for seizures requires careful consideration of variant type. For gain-of-function variants, sodium channel blockers (such as phenytoin or carbamazepine) are often used. For loss-of-function variants, the same medications may worsen the condition, making accurate genetic diagnosis essential before treatment decisions.
Early intervention programmes, occupational therapy, speech pathology, and physiotherapy are valuable for supporting development in children with SCN2A-related disorders. Earlier engagement typically leads to better developmental outcomes.
Most individuals with SCN2A-related disorders benefit from a coordinated care team that may include a paediatric neurologist, developmental paediatrician, geneticist, genetic counsellor, occupational therapist, speech pathologist, and psychologist.
Research into precision-medicine approaches, including antisense oligonucleotides (ASOs) and other targeted therapies, is advancing rapidly. SCN2A Australia tracks and translates this research for families. Several clinical trials have been conducted or are in development specifically for SCN2A.
SCN2A-related disorders are rare. Exact prevalence figures are still being established through natural-history research, but SCN2A is considered one of the more commonly identified single-gene causes of early infantile epileptic encephalopathy.
Because the condition exists on a spectrum, from severe early-onset epilepsy to autism with no seizures, it is likely underdiagnosed in individuals with milder presentations. Improved access to genetic testing is helping to identify more families.
Every person's body is built according to a set of instructions encoded in DNA. These instructions are organised into units called genes, each one responsible for a particular function in the body. Humans have tens of thousands of genes, and together they influence everything from eye colour to how the brain develops.
Sometimes, a gene contains a change, called a variant, that affects how it works. In the case of SCN2A and other genes associated with DEE, the relevant gene change affects how the brain develops and how its electrical activity is regulated.
Not all gene variants are significant. Some are common variations that don't affect health at all. Others, called pathogenic variants, are known to cause or significantly contribute to a health condition.
For most families, a genetic diagnosis follows a period of clinical concern, often after seizures, developmental delays, or other neurological features have prompted investigation.
A paediatric neurologist or developmental paediatrician assesses your child's presentation: their symptoms, development, and medical history. This guides which investigations are ordered.
An EEG (electroencephalogram) measures brain electrical activity and can identify abnormal patterns associated with epilepsy. Brain MRI may also be performed to look for structural abnormalities.
If a genetic cause is suspected, genetic testing is recommended. This may take several forms:
In Australia, genetic testing is typically arranged through a clinical genetics service or a paediatric neurologist.
If your child's SCN2A variant is confirmed as de novo, the likelihood of the same variant occurring in a future sibling is low, approximately 1%, due to the small chance of the same spontaneous change occurring again. This is sometimes referred to as gonadal mosaicism: the possibility that a small number of egg or sperm cells in a parent carry the variant, even though a standard blood test did not detect it.
Given this small recurrence risk, families planning future pregnancies are encouraged to discuss options with a clinical genetics service before conception. Prenatal genetic testing is available for families in this situation.
If a variant is inherited rather than de novo, the recurrence risk is higher and depends on the inheritance pattern of the specific variant. A genetic counsellor can advise on this in the context of your family's specific result.
A genetic counsellor is a health professional specialising in genetic conditions. They are trained to help families understand what a genetic result means, for their child, for other family members, and for future family planning.
Genetic counselling is not just about understanding numbers and probabilities. It also helps families process the emotional aspects of receiving a genetic diagnosis and make informed decisions about testing, management, and family planning.
SCN2A Australia can help connect you with a clinical genetics service or genetic counsellor experienced in neurodevelopmental conditions. If your child's treating team has not yet arranged genetic counselling, it is worth requesting a referral.
One of the most clinically important questions for any family with an SCN2A diagnosis is whether the variant is a gain of function (GoF) or loss of function (LoF) variant. This distinction affects which anti-seizure medications are likely to be helpful, and which may need to be avoided.
For many families, the path to a confirmed genetic diagnosis is not straightforward. It may involve multiple rounds of testing, second opinions, and a period of living with uncertainty. A "variant of uncertain significance" result, or a normal genetic test result despite a clear clinical picture, does not mean that something is not wrong, it means that current testing has not yet identified the cause.
Genetic testing technology is improving rapidly. Variants that cannot be explained today may be reclassified as research advances, and whole genome sequencing is identifying causes in families where earlier tests found nothing.
SCN2A Australia can help you navigate the diagnostic process, whether you are still seeking a diagnosis, trying to understand a recent result, or considering further testing.