Epilepsy Research Findings: July 2019

This month’s edition of epilepsy news features recent research suggesting that inducing a seizure prior to surgery is just as effective for pinpointing the brain region where seizures originate as a spontaneous seizure as a spontaneous seizure. In addition, CURE Post-Traumatic Epilepsy initiative members Dr. Oleskii Shandra and Dr. Stefanie Robel published work indicating that the amount of a certain type of cell may increase in the brain following repeated, mild TBIs, causing epilepsy.

Safety updates on several anti-epileptic drugs were reported, including results showing pregabalin may be associated with increased suicidal behavior and other hazards, and that certain drugs used to treat epilepsy may increase the risk of dementia. Studies also highlight the need for improved counseling for safe and effective contraception for women with epilepsy, and the need for resources for people with epilepsy in low-income countries.

Summaries of all highlighted studies follow below. We have organized the findings into Research and Discoveries and Also Notable.

Research and Discoveries

Inducing Seizures to Stop Seizures
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Causing seizures by stimulating the brain may be a convenient and more cost-effective way to determine the brain region where seizures are originating prior to surgery.

New Research Could Help Predict Seizures Before They Happen
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A new study has found a pattern of molecules that appears in the blood before a seizure happens, which may lead to the development of an early warning system.

Pregabalin Associated with Increased Suicidal Behavior and Other Hazards 
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Gabapentinoids, a class of drugs used to treat epilepsy and other neurological disorders, are associated with an increased risk of suicidal behavior, unintentional overdoses, head/body injuries, and road traffic incidents and offences. Pregabalin was associated with higher hazards of these outcomes than gabapentin.

Study Furthers Understanding of the Development of Epilepsy Following Mild Traumatic Brain Injury (TBI)
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Featuring the work of CURE PTE Initiative members Dr. Oleskii Shandra and Dr. Stefanie Robel

A type of cell in the brain called an “atypical astrocyte” may increase following trauma, causing epilepsy following repeated, mild TBIs, according to a study by Drs. Oleskii Shandra and Stefanie Robel.

Even People with Well-Controlled Epilepsy May Be at Risk for Sudden Death
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Featuring the work of former CURE Grantee Elizabeth Donner

A new study shows the risk of Sudden Unexpected Death in Epilepsy (SUDEP) may apply to individuals whose epilepsy is well-controlled. Previous, smaller studies showed that SUDEP risk was highest among those with severe, difficult-to-treat epilepsy, however, this study suggests a sizeable minority of SUDEP occurred in patients thought to be treatment-responsive or to have benign epilepsies. The study found that SUDEP occurred in people who had not taken their last dose of epilepsy medication, those who were sleep deprived, and those who had not had a seizure in at least a year.

Anticholinergic Drugs May Increase Risk of Dementia 
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A study suggests that the possible link between anticholinergic drugs and an increased risk of dementia is strongest for certain classes of anticholinergic drugs, including antiepileptic drugs such as oxcarbazepine and carbamazepine.

Research into Cannabis Dosage Shows Reduced Seizures in Children with Severe Epilepsy
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Medicinal cannabis oil containing both cannabidiol (CBD) and a small amount of tetrahydrocannabinol (THC) can reduce or end seizures in children with severe, drug-resistant epilepsy, a study by the University of Saskatchewan has found.

Also Notable

The World Health Organization (WHO) Highlights the Scarcity of Treatment for Epilepsy in Low-Income Countries
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Three quarters of people living with epilepsy in low-income countries do not get the treatment they need, increasing their risk of dying prematurely and condemning many to a life of stigma, according to WHO.

Bringing Neuromodulation Therapies to Drug-Resistant Epilepsy Patients
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Researchers at the University of Alabama at Birmingham found that creating an epilepsy neuromodulation clinic improved access for patients and communication with referring physicians, achievement of expected outcomes for reducing or eliminating seizures, and the ability to train future providers in programming neuromodulation devices.

Encoded Therapeutics Gets $104M to Propel ‘Precision Gene Therapy’ for Dravet Syndrome
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Encoded Therapeutics received $104 million to fund a precision gene therapy for Dravet syndrome. The company will also use the funds to advance its preclinical programs and come up with new treatments for severe genetic disorders.

Improved Counseling Needed for Safe, Effective Contraception in Women With Epilepsy
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Over a third of women with epilepsy do not use highly effective contraception, despite the important, negative consequences of unintended pregnancy such as elevated risk of having offspring with congenital malformations. There is a need for more readily available information and counseling on safe and effective contraception for this community.

SCN8A: When Neurons Are So Excited, They Just Can’t Hide It

In this study, researchers identify a set of neurons in the brain as critical targets for therapeutic intervention, utilizing a mouse model mimicking a mutation of the sodium channel gene SCN8A found in 14 individuals with epilepsy. These individuals had seizures that began in the prenatal or infantile period as well as severe verbal delays. The researchers report that this mutation resulted in seizures in both juvenile and adult mice, suggesting that successful therapy would require lifelong treatment.

Epilepsy Research UK (ERUK) Fellow Awarded Prestigious MRC Grant To Investigate Dravet Syndrome

2017 ERUK Fellow Dr Gabriele Lignani, has been awarded a New Investigator Research Grant, worth nearly £700,000 by the Medical Research Council (MRC), to investigate the potential use of gene therapy in Dravet syndrome. This research project will build on Dr Lignani’s ongoing fellowship research – GeneLoop, which is currently investigating the potential of gene therapy as a treatment for acquired intractable epilepsy.

Dravet Syndrome is a severe and extremely rare but catastrophic neurological disorder affecting young children (approximately 1 in 19,000 people). Every day 3 or 4 children are diagnosed with Dravet syndrome worldwide, with symptoms including epilepsy, autism, movement disorders, and sleep disturbances. To date, the majority of therapies are ineffective or poorly tolerated. Sodium channel drugs, which are some of the most commonly prescribed and effective antiepileptic drugs may even worsen Dravet syndrome.

Dr Lignani said: “This research will be useful not only to understand if a permanent general treatment for Dravet syndrome is achievable, but will also give insight into the potential of the techniques to cure other neurological conditions caused by similar mutations in different genes.”

He continued “This research will be useful not only to understand if a permanent general treatment for Dravet syndrome is achievable, but will also give insight into the potential of the techniques to cure other neurological conditions caused by similar mutations in different genes.”

Dr Lignani’s ERUK Fellowship officially began in 2018 but is already showing promising results. His team’s work thus far has focused on developing and testing their gene therapy tools, and they have found that this tool is able to subdue neurons during epileptic activity. The following stages of the fellowship will involve trialing these tools in models of acquired intractable epilepsy.

Use of Next-Generation Sequencing Panel as First-Tier in Diagnostic Process May Enable Precision Medicine

Objective: Molecular genetic etiologies in epilepsy have become better understood in recent years, creating important opportunities for precision medicine. Building on these advances, detailed studies of the complexities and outcomes of genetic testing for epilepsy can provide useful insights that inform and refine diagnostic approaches and illuminate the potential for precision medicine in epilepsy.

Methods: Researchers used a multi-gene next-generation sequencing (NGS) panel with simultaneous sequence and exonic copy number variant detection to investigate up to 183 epilepsy-related genes in 9,769 individuals. Clinical variant interpretation was performed using a semi-quantitative scoring system based on existing professional practice guidelines.

Results: Molecular genetic testing provided a diagnosis in 14.9-24.4% of individuals with epilepsy, depending on the NGS panel used. More than half of these diagnoses were in children younger than 5 years. Notably, the testing had possible precision medicine implications in 33% of individuals who received definitive diagnostic results. Only 30 genes provided 80% of molecular diagnoses. While most clinically significant findings were single-nucleotide variants, ~15% were other types that are often challenging to detect with traditional methods. In addition to clinically significant variants, there were many others that initially had uncertain significance; reclassification of 1612 such variants with parental testing or other evidence contributed to 18.5% of diagnostic results overall and 6.1% of results with precision medicine implications.

Significance: Using a next-generation sequencing panel with key high-yield genes and robust analytic sensitivity as a first-tier test early in the diagnostic process, especially for children younger than 5 years, can possibly enable precision medicine approaches in a significant number of individuals with epilepsy.

Encoded Therapeutics Bags $104M to Propel ‘Precision Gene Therapy’ for Dravet Syndrome

Encoded Therapeutics reeled in $104 million in series C cash to bankroll the development of its lead program: a precision gene therapy for Dravet syndrome, a rare form of epilepsy. The Bay Area biotech will also use the funds to push its preclinical programs and come up with new treatments for severe genetic disorders.

The company’s work is based on a platform designed to overcome hurdles it has identified in the gene therapy space. Gene therapies tend to work in one of three ways: They deliver a healthy copy of a faulty gene, introduce a new gene into the body or “knock out” a defective gene. But they can run into problems with cell selectivity, potency and the ability to control endogenous genes, Encoded CEO Karthik Ramamoorthi, Ph.D., told FierceBiotech.

“We’ve developed a series of technologies that are both computational and genomics- or sequencing-based that allow us to screen for and identify sequences in vivo that control where and when genes are able to be expressed,” Ramamoorthi said. “We take these sequences and place them in gene therapies—such as adeno-associated viruses (AAVs)—that allow us to control where the adeno-associated viruses are able to express the payload.”

Clinical Evolution and Epilepsy Outcome in Three Patients with CDKL5-Related Developmental Encephalopathy

Objective: To further characterize CDKL5-related disorder, previously classified as an early-onset seizure variant of Rett syndrome, which is currently considered a specific and independent early-infantile epileptic encephalopathy.

Results: Researchers describe the epileptic phenotype and neurocognitive development in three girls with CDKL5 mutations showing severe neurodevelopmental impairment, with different epileptic phenotypes and severity. The patients differed regarding age at epilepsy onset, seizure frequency, duration of “honeymoon periods”, as well as EEG features. The “honeymoon period”, defined as a seizure-free period longer than two months, represented, in this case series, a good indicator of the epilepsy outcome, but not of the severity of developmental impairment. However, even during the “honeymoon period”, the interictal EEG showed epileptiform abnormalities, slowing, or a disappearance of physiological pattern. The natural history of CDKL5 disorder was compared between the three girls, focusing on the relationship between electroclinical features and neurological development.

Significance: These findings suggest that CDKL5 mutations likely play a direct role in psychomotor development, whereas epilepsy is one of the clinical features associated with this complex disorder.

Epilepsy Research Findings: June 2019

This month’s round-up of epilepsy news features an announcement about a new antiepileptic rescue medication, NAYZILAM®. This therapy is the first FDA-approved nasal treatment option for people with epilepsy who experience episodes of frequent seizure activity.

We also highlight many research advances, from the discovery of a compound found in fruit and honey which can inhibit seizures to the development of a new drug to treat Dravet syndrome. Research in the cannabidiol (CBD) space has also advanced, with the creation of a synthetic form of CBD which may be easier to purify and does not need to be cultivated from hemp plants.

In more sobering news, reports over the past month show that one-third of epilepsy cases go without appropriate treatment for up to three years following diagnosis. In addition, people with psychogenic nonepileptic seizures (PNES) as well as epileptic seizures may be at a higher risk for sudden unexpected death in epilepsy (SUDEP)during the years immediately following diagnosis with PNES.

Summaries of all highlighted studies follow below. I’ve organized the findings into three categories: Treatment Advances, Research Discoveries, and Also Notable.

Treatment Advances

FDA Approves NAYZILAM® Nasal Spray to Treat Intermittent, Stereotypic Episodes of Frequent Seizure Activity in People Living with Epilepsy in the US
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The FDA has approved a New Drug Application for UCB’s newest antiepileptic drug NAYZILAM® (midazolam) nasal spray. This therapy is a benzodiazepine indicated for the acute treatment of intermittent, stereotypic episodes of frequent seizure activity (i.e., seizure clusters, acute repetitive seizures) distinct from a patient’s usual seizure pattern in individuals with epilepsy who are 12 years of age and older.

Study Advances More Effective Laser Ablation and Standard Epilepsy Surgery 
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In the largest study of its kind to date, researchers across 11 centers analyzed data on a relatively new minimally invasive alternative surgery for epilepsy. These researchers discovered changes that could make the procedure more effective in both laser ablation and standard surgery.

Research Discoveries

Brain Network Activity can Improve in Epilepsy Patients after Surgery
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Successful epilepsy surgery can improve brain connectivity similar to patterns seen in people without epilepsy, according to a new study published in the journal Neurosurgery. The study of 15 people with temporal lobe epilepsy is the first to show improvements in brain networks after surgery compared to a group of healthy subjects.

New Drug Could Help Treat Neonatal Seizures
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A new drug that inhibits neonatal seizures in rodent models could open new avenues for epilepsy treatment in human newborns. Researchers have found that gluconate—a small organic compound found in fruit and honey—acts as an anticonvulsant, inhibiting seizures by targeting the activity of channels that control the flow of chloride ions in and out of neonatal neurons.

Research Looks to Halt Stress-Induced Seizures Following Brain Injury
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The likelihood of developing epilepsy increases significantly with a traumatic brain injury. Stress and anxiety increase that likelihood even more dramatically. Researchers have been able to demonstrate that an injured brain responds differently to stress hormones than a healthy brain. The research team showed abnormal electrical activity in the brain tied to these stress-induced seizures and, most importantly, found a way to stop this activity from occurring.

Synthetic Version of Cannabidiol (CBD) Treats Seizures in Rats
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A synthetic, non-intoxicating analogue of CBD was found to be effective for treating seizures in rats. Researchers note the synthetic CBD alternative is easier to purify than a plant extract, eliminates the need to use agricultural land for hemp cultivation, and could avoid legal complications associated with cannabis-related products.

AZD7325 Has Seizure-Protective Effect in Mouse Model of Dravet Syndrome, Study Says
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Treatment with AZD7325, a compound that stimulates an inhibitory receptor in the brain, has a seizure-protective effect in a mouse model of Dravet syndrome. This treatment significantly increased the temperature threshold animals could withstand without experiencing any seizures during a hyperthermia-induced seizure test.

Children’s Brains Reorganize after Epilepsy Surgery to Retain Visual Perception
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Children can keep their full ability to process and understand visual information after brain surgery for severe epilepsy, according to a study funded by the National Eye Institute, part of the National Institutes of Health. This new report from a study of children who underwent epilepsy surgery and suggests that the lasting effects on visual perception can be minimal, even among children who lost tissue in the brain’s visual centers.

One-Third of Epilepsy Cases Go Untreated up to 3 Years After Diagnosis
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A small yet substantial subset of patients with newly diagnosed epilepsy go without appropriate treatment approximately 3 years after diagnosis. This gap in treatment may be increasing the risk for medical events and hospitalization in these patients.

Study Suggests ‘High Risk Period’ for SUDEP for People with Psychogenic Nonepileptic Seizures in Addition to Epileptic Seizures 
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Findings of a recently published study suggest that patients with comorbid epileptic seizures (ES) and Psychogenic Nonepileptic Seizures (PNES) can die from SUDEP and that there may be a high?risk period after the diagnosis of PNES is made. The authors state such patients should be closely monitored and provided with coordinated care of both their epilepsy and psychiatric disorder(s).

Also Notable

Fralin Biomedical Research Institute Neuroscientist Awarded Grant to Study Epilepsy
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Featuring CURE Grantee Dr. Sharon Swanger

Dr. Sharon Swanger of the Fralin Biomedical Research Institute was recently awarded a $1.7 million grant through the National Institute of Neurological Disorders and Stroke to study the role of glutamate receptors in the thalamus – an area of the brain involved in seizure generation. “If we can figure out how each [receptor] subtype functions and modulate select subtypes, then maybe we can target therapies to the circuit where the disease originated while leaving healthy circuits intact,” said Dr. Swanger.

Tool Helps GPs Predict Risk of Seizures in Pregnancy
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Doctors, midwives, and others can use a new risk calculator to identify those pregnant women at high-risk of seizures and to plan early referral for specialist input. The specialist could determine the need for close monitoring in pregnancy, labor, and after birth, and assess antiepileptic drug management, according to new research in PLOS Medicine. The study authors added that the model’s performance is unlikely to vary with the antiepilepsy drug dose management strategy – and that it could save maternal and infant lives.

Development of Epilepsy Prediction Device to Improve Independence for People with Epilepsy
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The University of Sydney’s Faculty of Engineering and Information Technologies is developing a system, NeuroSyd, which aims at real-time monitoring and processing of brain-signals while driving in a group of people living with epilepsy. NeuroSyd will be developed to deliver an early warning of the likelihood of an epileptic seizure.

Pfizer’s Lyrica at Doses 5mg and 10mg Fails Phase 3 Trial in Epilepsy
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Pfizer’s Lyrica has failed to meet its primary endpoint in a phase 3 trial in primary generalized tonic-clonic (PGTC) seizures. The study evaluated two doses of the drug – 5 mg and 10 mg – over a period of 12 weeks. Treatment with the drug did not result in a statistically significant reduction in seizure frequency versus placebo. Another phase 3 trial in May 2018 was successful, showing that a 14 mg dose of Lyrica resulted in a statistically significant reduction in seizure frequency versus placebo.

Advancing Science for Children with Epilepsy and Movement Disorders

Two Michigan State University College of Osteopathic Medicine graduate students are advancing the science behind genetic mutations that cause rare forms of epilepsy and movement disorders.

Huijie Feng, a doctoral student in the Department of Pharmacology and Toxicology, and Casandra Larrivee, a master’s student in the comparative medicine and integrative biology program, have found that different mutations in the GNAO1 gene in mice correlate to different characteristics, or phenotypes, of movement disorders in humans.

The findings are published in PLoS ONE.

The work adds to research started in 2013 by Richard Neubig, professor and chair of MSU’s pharmacology and toxicology department, whose focus at that time was on cardiovascular disease.

While using mice with a GNAO1 protein mutation, one unexpectedly had a seizure. This begged the question of whether the mutation could be linked to a seizure disorder.

Further investigation indicated that these mice were prone to seizures and soon after, four children who earlier had been diagnosed with Early Infantile Epileptic Encephalopathy, or EIEE, were also found to have the same mutations.

CURE Discovery: New Genetic Models of Epileptic Encephalopathies Deepen Our Understanding

This research is generously supported by a grant from Jen Scott and Pierre-Gilles Henry, PhD, in honor of Felix Henry.

Key Points

  • CURE grantee Dr. Mingshan Xue created mice modeling the features of STXBP1-related epileptic encephalopathy (EE) to explore why not having enough STXBP1 activity can cause epilepsy.
  • The team found that inhibitory brain signaling was diminished in the models, causing excessive neuronal excitation, seizures, and other neurological features seen in humans with EE.
  • The long-term goal of the team’s project is to understand the mechanisms that cause EEs and use this knowledge to develop new therapies.

Deep Dive

Reduced activity of a gene called STXBP1 is one of the most common causes of epileptic encephalopathy (EE),1a group of severe pediatric epilepsies which includes Ohtahara Syndrome, West Syndrome, and Dravet Syndrome. Patients with EE often have aggressive, treatment-resistant seizures, developmental delays, behavioral deficits, and intellectual disability among other clinical features. There is an urgent need to better understand these syndromes and develop new therapies for them.

CURE grantee Dr. Mingshan Xue and his colleagues at the Baylor College of Medicine created mouse models with reduced STXBP1 activity to study epilepsy associated with this genetic variant. Through extensive testing, they determined these mice accurately represented EE clinical features such as seizures, behavioral, and cognitive deficits.2

For their CURE-funded work, the team used these models to determine how not having enough STXBP1 activity could cause EE. The team previously observed high levels of neuronal excitation in the brains of mice with low STXBP1. Thus, Dr. Xue’s team hypothesized that not having enough STXBP1 must prevent inhibitory neuronal signaling, causing an imbalance between excitation and inhibition in the brain.

To test this, the team recorded the electrical activity of neurons in the model with reduced STXBP1 activity. They found that inhibitory brain signaling was indeed diminished in these mice while excitatory signaling was not affected, resulting in excessive excitation, seizures, and other neurological features of EE. Further testing revealed that mice with reduced STXBP1 activity specifically in inhibitory neurons had higher anxiety, impaired motor skills, and reduced cognitive function – all features that are seen in humans with EE.

EEs are typically hard to treat with currently available options. The team’s long-term goal is to understand the mechanisms that cause EEs and use this knowledge to develop new therapies. Since completing their CURE-funded grant, Dr. Xue and his co-investigator have received a National Institutes of Health grant, as well as an American Epilepsy Society postdoctoral fellowship to continue this important work.

Bridging the Gap Between STXBP1 Researchers and Families

We are honored to sponsor and attend the first ever STXBP1 Investigators and Family Meeting (SIFM) on June 21, 2019 and June 22, 2019 in Philadelphia. This conference is hosted by STXBP1 Foundation and the Center for Cellular and Molecular Therapeutics (CCMT).

The need for developing community and driving more research on this group of EEs is clear. The inaugural SIFM will bring together researchers and families of individuals with STXBP1 encephalopathies to foster community development and accelerate the search for a cure. This conference is designed to encourage interaction and in-depth discussions among researchers and clinicians to further research and innovation in this field.

You can find out more information about this conference here.

1 Carvill GL et.al. Nat Genet. 2013 Jul;45(7):825-30. doi: 10.1038/ng.2646
2 Wu Chen et.al., Apr 29, 2019, https://www.biorxiv.org/content/10.1101/621516v1

Clinical Study Finds Two Types of SCN8A-Related Epilepsy: Slowly Emerging or Sudden Onset of Epilepsy

Objective: To describe the mode of onset of SCN8A-related severe epilepsy in order to facilitate early recognition, and eventually early treatment with sodium channel blockers.

Methods: Researchers reviewed the phenotype of patients carrying a mutation in the SCN8A gene, among a multicentric cohort of 638 patients prospectively followed by several pediatric neurologists. The study focused on the way clinicians made the diagnosis of epileptic encephalopathy, the very first symptoms, electroencephalography (EEG) findings, and seizure types. The team made genotypic/phenotypic correlation based on epilepsy-associated missense variant localization over the protein.

Results: The study found 19 patients carrying a de novo mutation of SCN8A, representing 3% of our cohort, with 9 mutations being novel. Age at onset of epilepsy was 1 day to 16 months. The team also found two modes of onset: 12 patients had slowly emerging onset with rare and/or subtle seizures and normal interictal EEG (group 1). The first event was either acute generalized tonic-clonic seizure (GTCS; Group  1a, n = 6) or episodes of myoclonic jerks that were often mistaken for sleep-related movements or other movement disorders (Group 1b, n = 6). Seven patients had a sudden onset of frequent tonic seizures or epileptic spasms with abnormal interictal EEG leading to rapid diagnosis of epileptic encephalopathy. Sodium channel blockers were effective or nonaggravating in most cases.

Significance: SCN8A is the third most prevalent early onset epileptic encephalopathy gene and is associated with two modes of onset of epilepsy.