Monozygous twin brothers discordant for photosensitive epilepsy: first report of possible visual priming in humans.
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.
de Haan
Gerrit-Jan
GJ
Epilepsy Institute of the Netherlands SEIN, Heemstede, the Netherlands. gjdhaan@sein.nl
Trenité
Dorothee Kasteleijn-Nolst
DK
Stroink
Hans
H
Parra
Jaime
J
Voskuyl
Rob
R
van Kempen
Marian
M
Lindhout
Dick
D
Bertram
Ed
E
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