title: Analyzing the etiology of benign rolandic epilepsy: a multicenter twin collaboration.
abstract: OBJECTIVE
  Benign rolandic epilepsy (BRE) is considered a genetically determined idiopathic partial epilepsy. We analyzed a large sample of twins from four international twin registers to probe the genetics of BRE. We also aim to synthesize the apparently conflicting family and twin data into a model of BRE etiology.
  
  
  METHODS
  Large population-based twin registries of epilepsies from Odense (Denmark), Richmond, Virginia (United States), and Oslo (Norway) were reviewed for BRE cases and added to our Australian twin data. Diagnosis of classic BRE was based on electroclinical criteria with normal neurologic development. Cases with a compatible electroclinical picture but abnormal neurologic development were termed non-classic BRE.
  
  
  RESULTS
  Eighteen twin pairs were identified (10 monozygous; eight dizygous) of whom at least one twin was diagnosed with classic BRE among a total sample of 1,952 twin pairs validated for seizures, and all were discordant for BRE. The estimated monozygous pairwise concordance for BRE in this sample was 0.0 [95% confidence interval (CI), 0.0-0.3). Four twin pairs (one monozygous, three dizygous) had non-classic BRE, and all co-twins had seizures.
  
  
  CONCLUSIONS
  The twin data showing an absence of any concordant twin pairs with classic BRE suggest that noninherited factors are of major importance in BRE. Modelling the data shows that the familial occurrence of centrotemporal spikes makes only a minor contribution to the familial aggregation of BRE. Genetic factors are probably more important in non-classic BRE. The etiology and mode(s) of inheritance of BRE are much more complicated than initially conceptualized.
authors.affiliation: Epilepsy Research Centre, Department of Medicine (Neurology), University of Melbourne, Austin Health, Heidelberg, Victoria, Australia.
authors.forename: Lata
authors.initials: L
authors.lastname: Vadlamudi
authors.forename: Marianne J
authors.initials: MJ
authors.lastname: Kjeldsen
authors.forename: Linda A
authors.initials: LA
authors.lastname: Corey
authors.forename: Marit H
authors.initials: MH
authors.lastname: Solaas
authors.forename: Mogen L
authors.initials: ML
authors.lastname: Friis
authors.forename: John M
authors.initials: JM
authors.lastname: Pellock
authors.forename: Karl O
authors.initials: KO
authors.lastname: Nakken
authors.forename: Roger L
authors.initials: RL
authors.lastname: Milne
authors.forename: Ingrid E
authors.initials: IE
authors.lastname: Scheffer
authors.forename: A Simon
authors.initials: AS
authors.lastname: Harvey
authors.forename: John L
authors.initials: JL
authors.lastname: Hopper
authors.forename: Samuel F
authors.initials: SF
authors.lastname: Berkovic
mesh_terms: D000328:Adult; D017668:Age of Onset; D001315:Australia / Q000453:epidemiology; D003718:Denmark / Q000453:epidemiology; D004200:Diseases in Twins / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D004569:Electroencephalography / Q000706:statistics & numerical data; D019305:Epilepsy, Rolandic / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D005190:Family; D005260:Female; D018740:Genetic Heterogeneity; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008297:Male; D008957:Models, Genetic; D009664:Norway / Q000453:epidemiology; D010375:Pedigree; D015995:Prevalence; D014429:Twins, Dizygotic / Q000235:genetics; D014430:Twins, Monozygotic / Q000235:genetics; D014481:United States / Q000453:epidemiology