Six patients aged 6 to 27 years (mean, 14 years) with childhood absence epilepsy and paroxysmal dyskinesia (PD), identified at five European centers participating in a study group, are reported from Great Ormond Street Hospital, London, UK. The onset of absence seizures was early, at a mean age of 16 months (range, 3 months to 3 years 6 months), and seizures remitted between age 8 and 13 years. The types of associated PD included paroxysmal kinesigenic dyskinesia (1 patient), paroxysmal exercise-induced dystonia (3 patients), and paroxysmal tonic upgaze (two siblings). Apart from the siblings with tonic upgaze which had an earlier onset, PD developed after the onset of absence seizures, and continued after seizures had remitted. PD improved with increasing age and was not severely disabling. Seizures and PD were idiopathic and were thought to be genetic. Seizures were accompanied by a characteristic 3 Hz spike-and-wave EEG and they responded to ethosuximide. [1]
COMMENT. Absence epilepsy and paroxysmal dyskinesias may coexist. The age at onset of absence seizures and 3 Hz spike-and-wave in this comorbid syndrome is unusually early, often in infancy.