title: A homozygous mutation of voltage-gated sodium channel β(I)  gene SCN1B in a patient with Dravet syndrome.
abstract: Dravet syndrome is a severe form of epileptic encephalopathy characterized by early onset epileptic seizures followed by ataxia and cognitive decline. Approximately 80% of patients with Dravet syndrome have been associated with heterozygous mutations in SCN1A gene encoding voltage-gated sodium channel (VGSC) α(I)  subunit, whereas a homozygous mutation (p.Arg125Cys) of SCN1B gene encoding VGSC β(I)  subunit was recently described in a patient with Dravet syndrome. To further examine the involvement of homozygous SCN1B mutations in the etiology of Dravet syndrome, we performed mutational analyses on SCN1B in 286 patients with epileptic disorders, including 67 patients with Dravet syndrome who have been negative for SCN1A and SCN2A mutations. In the cohort, we found one additional homozygous mutation (p.Ile106Phe) in a patient with Dravet syndrome. The identified homozygous SCN1B mutations indicate that SCN1B is an etiologic candidate underlying Dravet syndrome.
authors.affiliation: Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Ogiwara
authors.forename: Tojo
authors.initials: T
authors.lastname: Nakayama
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Yamagata
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ohtani
authors.forename: Emi
authors.initials: E
authors.lastname: Mazaki
authors.forename: Shigeru
authors.initials: S
authors.lastname: Tsuchiya
authors.forename: Yushi
authors.initials: Y
authors.lastname: Inoue
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamakawa
mesh_terms: D004252:DNA Mutational Analysis; D004831:Epilepsies, Myoclonic / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D062547:Voltage-Gated Sodium Channel beta-1 Subunit / Q000235:genetics*; D055815:Young Adult
chemical_list: C470379:SCN1B protein, human; D062547:Voltage-Gated Sodium Channel beta-1 Subunit