title: Monozygous twin brothers discordant for photosensitive epilepsy: first report of possible visual priming in humans.
abstract: OBJECTIVE
  The interaction of genetic predisposition and the environment in the development of epilepsy is often discussed, but, aside from some animal reflex epilepsies, little evidence supports such interaction in the development of reflex epilepsy in humans.
  
  
  METHODS
  We describe the history of a 16-year-old boy in whom photosensitive epilepsy developed after a period of weekly exposures to high-intensity light flashes.
  
  
  RESULTS
  Both he and his clinically unaffected monozygotic twin were found to be photosensitive.
  
  
  CONCLUSIONS
  This case report suggests that some genetic forms of human reflex epilepsy may be elicited by repeated environmental exposure to the appropriate stimulus, similar to some of the stimulus-induced epilepsies seen in animals.
authors.affiliation: Epilepsy Institute of the Netherlands SEIN, Heemstede, the Netherlands. gjdhaan@sein.nl
authors.forename: Gerrit-Jan
authors.initials: GJ
authors.lastname: de Haan
authors.forename: Dorothee Kasteleijn-Nolst
authors.initials: DK
authors.lastname: Trenité
authors.forename: Hans
authors.initials: H
authors.lastname: Stroink
authors.forename: Jaime
authors.initials: J
authors.lastname: Parra
authors.forename: Rob
authors.initials: R
authors.lastname: Voskuyl
authors.forename: Marian
authors.initials: M
authors.lastname: van Kempen
authors.forename: Dick
authors.initials: D
authors.lastname: Lindhout
authors.forename: Ed
authors.initials: E
authors.lastname: Bertram
mesh_terms: D000293:Adolescent; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics*; D004569:Electroencephalography / Q000706:statistics & numerical data; D004781:Environmental Exposure / Q000009:adverse effects*; D020195:Epilepsy, Reflex / Q000175:diagnosis / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006801:Humans; D007696:Kindling, Neurologic / Q000235:genetics*; D008297:Male; D010641:Phenotype; D010775:Photic Stimulation / Q000009:adverse effects*; D011998:Recreation; D035781:Siblings; D014430:Twins, Monozygotic