This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
SCN8A encephalopathy is a very rare form of early-onset epilepsy that causes multiple types of seizures and developmental delay or regression (loss of skills). Seizures begin during the first 18 months of life, at an average age of 4 months. Types of seizures may include generalized tonic-clonic seizures, infantile spasms, absence seizures, and focal seizures. Other signs and symptoms of SCN8A encephalopathy may include low muscle tone (hypotonia), a high pain tolerance, movement disorders (such as dystonia and ataxia), mild to severe intellectual disability, sleep problems, and autistic-like features. In some people with SCN8A encephalopathy, various other medical problems have been reported including hearing or vision problems, scoliosis, and difficulty regulating body temperature. About 10% of people with SCN8A encephalopathy reported in the literature have died from sudden unexpected death in epilepsy (SUDEP).
SCN8A encephalopathy is caused by mutations in the SCN8A gene. Inheritance is autosomal dominant, but most people with SCN8A encephalopathy have a new mutation in the gene that was not inherited from a parent. Treatment aims to control seizures with medications, which is extremely challenging. Seizure control should be managed by a pediatric neurologist with expertise in epilepsy who is familiar with SCN8A encephalopathy.
For more information, visit GARD.