Rare protein sequence variation in SV2A gene does not affect response to levetiracetam.

Levetiracetam, a broad spectrum antiepileptic drug, binds to membrane protein SV2A. The protein coding region of SV2A was sequenced in 158 patients with focal or generalized epilepsies divided into three groups based on their response to levetiracetam: responders (>75% decrease), exacerbators (50% increase) and non-responders. Nonsynonymous coding variation within SV2A was extremely rare, suggesting that rare variation is not likely to account for the individual differences in response to levetiracetam.