An epilepsy syndrome associated with infantile period seizures, complete or nearly-complete seizure remission afterwards, usually good developmental outcome, and dominant transmission with high penetrance in pedigrees. For most affected infants, seizures begin within the first week after term birth. In a minority, however, seizures can begin after the first week but within the first several months of life. At onset, seizures may be highly recurrent, and often feature unilateral tonic limb stiffening that may alternate sides from seizure to seizure, accompanied by cyanosis and autonomic features. Limb shaking movements occur, but not in the evolving rhythmic pattern of tonic-clonic convulsions in older individuals. Neurological examination of the infant is normal between seizures. Although these seizures remit by 4-12 months of age in the majority, 15-30% of those affected have one or more seizure recurrences later, including febrile seizures, focal-onset seizures, and convulsions. Although most affected children show typical development, individuals with mild learning difficulties have been reported in families where the majority develop typically.