Analyzing the etiology of benign rolandic epilepsy: a multicenter twin collaboration.
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.
Vadlamudi
Lata
L
Epilepsy Research Centre, Department of Medicine (Neurology), University of Melbourne, Austin Health, Heidelberg, Victoria, Australia.
Kjeldsen
Marianne J
MJ
Corey
Linda A
LA
Solaas
Marit H
MH
Friis
Mogen L
ML
Pellock
John M
JM
Nakken
Karl O
KO
Milne
Roger L
RL
Scheffer
Ingrid E
IE
Harvey
A Simon
AS
Hopper
John L
JL
Berkovic
Samuel F
SF
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