MedGen

An autosomal dominant condition caused by mutation(s) in the SCN1A gene, encoding sodium channel protein type 1 subunit alpha. It is characterized by isolated febrile seizures, typically with onset between 3 months to 5 years, with spontaneous remission by 6 years of age. Mutation(s) in the SCN1A gene are also responsible for generalized epilepsy with febrile seizures plus, type 2; and Dravet syndrome. [from NCI]

SCN1A seizure disorders encompass a spectrum that ranges from simple febrile seizures and generalized epilepsy with febrile seizures plus (GEFS+) at the mild end to Dravet syndrome and intractable childhood epilepsy with generalized tonic-clonic seizures (ICE-GTC) at the severe end. Phenotypes with intractable seizures including Dravet syndrome are often associated with cognitive decline. Less commonly observed phenotypes include myoclonic astatic epilepsy (MAE), Lennox-Gastaut syndrome, infantile spasms, epilepsy with focal seizures, and vaccine-related encephalopathy and seizures. The phenotype of SCN1A seizure disorders can vary even within the same family. [from GeneReviews]