Four children with Angelman syndrome (AS) showed worsening of seizures after introduction of vigabatrin (VGB), at the University Children’s Hospital, Zurich, Switzerland. Doses were 50-100 mg/kg/day in 3 and 150 mg/kg/day in 1. Improved seizure control followed reduction in dose of VGB to 35 mg/kg/day in one child. Myoclonic, astatic, tonic-clonic, and absence seizures were exacerbated. 
COMMENT. This report suggests that vigabatrin is contraindicated in children with Angelman syndrome and epilepsy, irrespective of the seizure type. Previous reports have found myoclonic seizures and atypical absences aggravated, but in the largest series, only 10% of epilepsies were exacerbated by VGB. Reasons for the unusual adverse effects of VGB in Angelman syndrome are undetermined.