title: Two mild cases of Dravet syndrome with truncating mutation of SCN1A.
abstract: BACKGROUND
  SCN1A is the gene that codes for the neuronal voltage-gated sodium-channel alpha-subunit 1. It is generally considered that an SCN1A truncating mutation causes the severe phenotype of Dravet syndrome.
  
  
  METHODS
  We describe 11- and 4-year-old male patients presenting with mild Dravet syndrome with a truncating mutation of SCN1A. The former patient showed moderate mental retardation; however, seizure was controlled to almost one incident a year by levetiracetam and topiramate. Carbamazepine was also effective, which is atypical of Dravet syndrome. The latter patient showed a borderline developmental quotient and did not have episodes of afebrile seizure.
  
  
  CONCLUSIONS
  Two patients presented with mild Dravet syndrome, even though they had a truncating mutation of SCN1A. Not all truncating mutations of SCN1A cause the severe phenotype of Dravet syndrome.
authors.affiliation: Department of Pediatrics, Kitano Hospital, The Tazuke Kofukai Medical Institute, Osaka, Japan. Electronic address: torutakaori@gmail.com.
authors.forename: Toru
authors.initials: T
authors.lastname: Takaori
authors.affiliation: Department of Pediatrics, Kitano Hospital, The Tazuke Kofukai Medical Institute, Osaka, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kumakura
authors.affiliation: Department of Pediatrics, Fukuoka University, Fukuoka, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ishii
authors.affiliation: Department of Pediatrics, Fukuoka University, Fukuoka, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Hirose
authors.affiliation: Department of Pediatrics, Kitano Hospital, The Tazuke Kofukai Medical Institute, Osaka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hata
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004831:Epilepsies, Myoclonic / Q000188:drug therapy / Q000235:genetics*; D006801:Humans; D008297:Male; D062550:NAV1.1 Voltage-Gated Sodium Channel / Q000235:genetics*; D010641:Phenotype; D017384:Sequence Deletion; D012720:Severity of Illness Index
chemical_list: D000927:Anticonvulsants; D062550:NAV1.1 Voltage-Gated Sodium Channel
keywords: Dravet syndrome; Mild phenotype; SCN1A truncating mutation