Emotion-induced myoclonic absence-like seizures in a patient with inv-dup(15) syndrome: a clinical, EEG, and molecular genetic study.

We have described a clinical EEG and molecular genetic study of a 9-year-old boy with inv-dup(15) syndrome in whom seizures were induced by emotionally gratifying stimuli. The reflex seizures began 5-20 s after the onset of repeated cheek-kissing from his mother or after viewing of pleasant or funny events. They were characterized by bilateral discharges involving mainly the temporal regions and evolving into myoclonic absence-like seizures. Nonemotional stimuli, such as a pinch, sucking or rubbing his cheeks, or the sound of the kiss alone, failed to provoke seizures. The seizures were resistant to antiepileptic (AED) treatments. Molecular genetic investigations revealed a correct methylation pattern of the chromosomes 15, and three copies (two maternal and one paternal) of the segment 15q11-q13, including the GABRb3 gene. We hypothesize that an overexpression of cerebral gamma-aminobutyric acid (GABA)-mediated inhibition accounts for the severe epilepsy that we observed in this patient.