SCN8A Epilepsy May Return In The Teen Years

What was studied

This was a single-patient case report about SCN8A-associated epilepsy. The report described a 19-year-old woman with a novel SCN8A gene change called c.791 T > C (p.Val264Ala). The variant was reported as de novo and heterozygous.

The authors described her seizure history, EEG findings, genetic testing, and response to treatment. They also discussed how SCN8A expression in the brain changes with age and how that might relate to her seizure pattern over time.

What they found

The patient had frequent cluster seizures with early onset, remission in childhood, and recurrence in adolescence. Her EEG showed multifocal epileptiform discharges. The variant was absent from gnomAD and multiple in silico tools predicted it to be damaging, so the authors evaluated it as "likely pathogenic" under ACMG guidelines.

Her seizures were controlled with the sodium channel blockers oxcarbazepine and lamotrigine. The authors said this clinical response suggests a possible gain-of-function effect of the variant, but this was not directly tested. They also stated that age-related changes in SCN8A expression in the brain may help explain the timing of remission and recurrence.

Limits of the evidence

This is only one case, so it cannot show that this pattern happens in most people with SCN8A variants. The report also cannot establish with certainty how this specific variant affects channel function.

The study did not include functional lab experiments on this variant, so the suggested gain-of-function effect is based on clinical response rather than direct testing. The proposed link between developmental changes in SCN8A expression and the patient’s clinical course is also an interpretation from the authors.

For families and caregivers

For families, this report suggests that SCN8A-related epilepsy can have a changing course over time, with seizures improving at one stage and returning later. It also suggests that some people with SCN8A variants may respond to sodium channel blocker medicines.

Still, this is a finding from one person, not a rule for everyone with SCN8A-related epilepsy. Families should not assume the same seizure pattern or treatment response will happen in another child or adult with SCN8A-related epilepsy.

What to watch next

Useful next steps would include reports of more patients with the same or similar SCN8A variants and lab testing to show how this variant affects channel function.

Terms in this summary

SCN8A

A gene that gives instructions for making the sodium channel NaV1.6, which is important for brain cell signaling.

de novo

A genetic change that is new in the person rather than inherited.

heterozygous

Having the gene change in one of the two copies of a gene.

EEG

A test that records the brain’s electrical activity.

multifocal epileptiform discharges

Abnormal EEG signals linked to seizures that come from more than one brain area.

developmental and epileptic encephalopathy

A condition involving epilepsy together with effects on development and brain function.

likely pathogenic

A genetic test label meaning the variant is considered likely to contribute to disease, but not proven with complete certainty.

gain-of-function

A change in a gene or protein that may make it more active than usual.