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SCN8A gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SCN8A gene

The SCN8A gene provides instructions for making a sodium channel that is critical for the generation and transmission of electrical signals in the brain and spinal cord.

Normal Function

The SCN8A gene belongs to a family of genes that provide instructions for making sodium channels. These channels allow positively charged sodium (Na) atoms (sodium ions) to pass into cells; they play a key role in a cell's ability to generate and transmit electrical signals.

The SCN8A gene provides instructions for making one part (the alpha subunit) of a sodium channel called Nav1.6. The alpha subunit forms the hole (pore) in the cell membrane through which sodium ions flow. Nav1.6 channels are primarily found in the nerve cells (neurons) of the brain and spinal cord (central nervous system) and neurons that connect the central nervous system to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound (the peripheral nervous system). Nav1.6 channels control the flow of sodium ions into cells, which makes it possible for neurons to communicate by generating and transmitting electrical signals.

Health Conditions Related to Genetic Changes

SCN8A-related epilepsy with encephalopathy

More than 100 mutations in the SCN8A gene have been found to cause SCN8A-related epilepsy with encephalopathy. This condition is characterized by recurrent seizures (epilepsy), abnormal brain function (encephalopathy), and intellectual disability. The signs and symptoms of this condition typically begin in infancy.

Most of these SCN8A gene mutations change a single protein building block (amino acid) in the Nav1.6 channel. The mutations that cause SCN8A-related epilepsy with encephalopathy result in altered channels that stay open longer than usual, which increases the flow of sodium ions into neurons. The persistently open channels abnormally increase electrical signals, which can lead to excess activation (excitation) of neurons in the brain. This increased neuronal activity leads to seizures in people with SCN8A-related epilepsy with encephalopathy.

Other disorders

Mutations in the SCN8A gene have been found to cause intellectual disability and movement problems in some individuals. Unlike the mutations that cause SCN8A-related epilepsy with encephalopathy, the SCN8A gene mutations that cause this condition result in the production of a Nav1.6 sodium channel that is less active than normal, resulting in a decrease in the flow of sodium into neurons. This change does not increase neuronal signaling, so individuals with these mutations do not develop seizures. Researchers suspect that decreased neuronal signaling in the part of the brain that coordinates movement is the likely cause of the movement problems.

Other SCN8A gene mutations can cause movement problems and seizures called benign infantile seizures, which usually develop in the first year of life and stop by age 3. Unlike most other individuals with SCN8A gene mutations, these individuals have normal intellectual function.

Other Names for This Gene

  • BFIS5
  • CERIII
  • CIAT
  • hNa6/Scn8a voltage-gated sodium channel
  • NaCh6
  • Nav1.6
  • sodium channel, voltage gated, type VIII, alpha subunit
  • voltage-gated sodium channel subunit alpha Nav1.6
  • voltage-gated sodium channel type VIII alpha protein

Frequently Asked Questions

Diagnosis usually involves a combination of clinical evaluation, including observing seizure types and developmental milestones, and genetic testing. Genetic testing specifically looks for mutations in the SCN8A gene. An electroencephalogram (EEG) may also be used to detect abnormal brain electrical activity, and brain imaging like MRI can assess for structural changes.
This condition typically begins in infancy. Parents might observe recurrent seizures, which can vary in type and severity. Other signs could include developmental delays, difficulties with feeding, or unusual movements. As the condition progresses, there may be signs of abnormal brain function or intellectual disability. Early recognition is crucial for timely diagnosis and management.
Most cases of SCN8A-related epilepsy with encephalopathy are caused by new (de novo) mutations, meaning they occur spontaneously in the affected individual and are not inherited from the parents. In such cases, the risk of recurrence in future children is generally low, though genetic counseling is recommended. Rarely, a parent might be a mosaic carrier, which could slightly increase recurrence risk.
Management focuses on controlling seizures and supporting development. This typically involves anti-seizure medications, which may need to be adjusted frequently due to the severity and complexity of the seizures. Other therapies, such as ketogenic diet or vagus nerve stimulation, might be considered. Comprehensive care also includes developmental therapies like physical, occupational, and speech therapy to address intellectual disability and improve quality of life.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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