title: SCN1A mutation mosaicism in a family with severe myoclonic epilepsy in infancy.
abstract: OBJECTIVE
  To investigate the genetic background of familial severe myoclonic epilepsy in infancy (SMEI) cases.
  
  
  METHODS
  We performed mutation analyses of the sodium-channel gene SCN1A in two Japanese brothers with clinical features of SMEI and their parents, who had no history of febrile and epileptic seizures.
  
  
  RESULTS
  Each patient showed nucleotide changes (c.[730G>T; 735G>T; 736A>T]) in the coding exon 6 of SCN1A that led to a truncation of the channel protein. Their father showed no mutations, but their mother showed the same mutation in a subpopulation of lymphocytes.
  
  
  CONCLUSIONS
  The maternal mosaicism explains the identical SCN1A mutations in the two brothers. This highlights the importance of investigating parental mosaicism even in sporadic SMEI cases.
authors.affiliation: Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan. morimoto@koto.kpu-m.ac.jp
authors.forename: Masafumi
authors.initials: M
authors.lastname: Morimoto
authors.forename: Emi
authors.initials: E
authors.lastname: Mazaki
authors.forename: Akira
authors.initials: A
authors.lastname: Nishimura
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Chiyonobu
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Sawai
authors.forename: Aki
authors.initials: A
authors.lastname: Murakami
authors.forename: Keiko
authors.initials: K
authors.lastname: Nakamura
authors.forename: Ikuyo
authors.initials: I
authors.lastname: Inoue
authors.forename: Ikuo
authors.initials: I
authors.lastname: Ogiwara
authors.forename: Tohru
authors.initials: T
authors.lastname: Sugimoto
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamakawa
mesh_terms: D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004831:Epilepsies, Myoclonic / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D053503:Epithelial Sodium Channels / Q000235:genetics*; D005190:Family; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D009030:Mosaicism / Q000706:statistics & numerical data*; D009154:Mutation / Q000235:genetics*; D010290:Parents; D035781:Siblings
chemical_list: D053503:Epithelial Sodium Channels; C507045:SCNN1A protein, human