title: Electroclinical features of epileptic encephalopathy caused by SCN8A mutation.
abstract: Voltage-gated sodium channel Nav 1.6, encoded by the gene SCN8A, plays a crucial role in controlling neuronal excitability. SCN8A mutations that cause increased channel activity are associated with seizures. We describe a patient with epileptic encephalopathy caused by de novo SCN8A mutation (c.5614C>T, p.Arg1872Trp). Seizures began 10 days after birth at which time brain magnetic resonance imaging (MRI) and electroencephalography (EEG) were normal. Seizure recurrence increased with age, leading to the development of frequent status epilepticus from 1 year of age. Seizure type included generalized tonic seizures and focal motor seizures. EEG first showed focal epileptic activity at the age of 4 months, and thereafter showed multifocal spikes. Serial MRI demonstrated brain atrophy, which appeared to progress with seizure aggravation. Clinical features that may give a clue to the diagnosis include normal EEG despite frequent seizures in early infancy and an increase in epileptic activity that occurs with aging.
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Akie
authors.initials: A
authors.lastname: Okayama
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Araki
authors.affiliation: Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan.
authors.forename: Hirotomo
authors.initials: H
authors.lastname: Saitsu
authors.affiliation: Department of Human Genetics, Graduate School of Medicine, Yokohama City University, Yokohama, Japan.
authors.forename: Naomichi
authors.initials: N
authors.lastname: Matsumoto
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Azuma
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use*; D004569:Electroencephalography; D004827:Epilepsy / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D009154:Mutation; D062557:NAV1.6 Voltage-Gated Sodium Channel / Q000235:genetics*
chemical_list: D000927:Anticonvulsants; D062557:NAV1.6 Voltage-Gated Sodium Channel
keywords: SCN8A; encephalopathy; epilepsy; mutation; sodium channel