As all babies grow cell by cell in their mother's womb, they develop small changes from their parents' genes. These changes happen by chance. Some are harmless, some are beneficial, and some cause diseases. SCN8A mutations can be the disease-causing kind.
One letter is out of place in a string of billions of letters. SCN8A is a rare disorder that causes a range of symptoms that can include severe epilepsy, developmental delay, and other medical challenges. Every person with this condition is affected differently and with varying severity. While choosing medications is a process of trial and error, with the help of several physicians, TCSF has developed a Clinician Reference Guide that can help guide your physician in best practices on medications to try (and to avoid).
What is SCN8A? SCN8A is a gene that encodes a voltage-gated sodium channel and affects how brain cells function. Mutations on this gene can cause neurological problems that can include epilepsy and learning difficulties. The SCN8A gene was isolated in mice in 1995, and the role of SCN8A in the human brain was discovered in 2012. Since then, ~550 patients have been diagnosed with SCN8A mutations. Due to advances in genetic testing, more patients are being discovered all the time. It is now believed that SCN8A mutations may cause up to 1% of all epilepsies. Watch SCN8A 101 below to learn more...
What problems do SCN8A mutations cause? Many with SCN8A mutations have epilepsy that is resistant to treatment - they may have seizures every day and need to be hospitalized often. Non-seizure symptoms often include learning difficulties, muscle spasms, low or high muscle tone, poor coordination, developmental delay, and autism spectrum disorder. Many children will have trouble learning to speak, and some will need assistance from feeding tubes to get the nourishment they need to grow.
Seizures in SCN8A Epilepsy typically onset between 0-18 months, at a mean age of 5 months. Seizures in SCN8A Epilepsy are often refractory—tonic-clonic seizures are the most typical, myoclonic and absence seizures are also common. Children with SCN8A mutations often have some degree of developmental delay which may occur from birth or onset with seizures. About half of those with SCN8A mutations have intellectual disability. Many others also have autistic-like features, hypotonia, and movement disorders—including dystonia and choreoathetosis. Learn more about some of our SCN8A warriors...
There is still much to be discovered about SCN8A and it's effects. While many have epilepsy and other medical challenges, some may develop fairly typically, and others may never have any seizures. It is important to get connected with our community and get involved in research, so we can understand the full spectrum of this disorder.
What is the treatment for SCN8A? There is currently no standard treatment for SCN8A. Treatment will depend on the type and severity of symptoms. SCN8A epilepsy is commonly drug resistant, but has shown a positive response to sodium channel blockers in many cases. A combination of treatments such as medications, implantable devices (VNS or RNS), or the ketogenic diet may be helpful.
The gene SCN8A was isolated in humans by Michael Hammer, PhD, a geneticist who found the gene in his own daughter, Shay. We celebrate International SCN8A Awareness Day on February 9th in memory of Shay. You can learn more about Dr. Hammer and Shay in The Gene Detective's Journey: