Electroencephalographic and epilepsy findings in mecp2 duplication syndrome. A family study

MECP2 duplication syndrome (MECP2 DS) is an X-linked disorder characterized by early-onset hypotonia, poor speech development, recurrent respiratory infections, epilepsy and progressive spasticity. Epilepsy occurs in more than 50% of the affected patients. Generalized tonic-clonic seizures (GTCS) are the most common seizure-type described but atonic seizures, absences and myoclonic seizures have also been reported. Electroencephalographic (EEG) and seizure types occurring in MECP2 DS have been poorly investigated. Here we report on two male siblings carrying a maternally-inherited MECP2 duplication. Patients underwent several EEG recordings and long-lasting video-EEG monitoring. The most represented seizure types were myoclonic and atonic seizures. GTCS were rarely observed. In patients, we found a slowing of the background activity with multifocal paroxysmal activity, prominent on the frontal areas. In conclusion, our observations seem to suggest that MECP2 syndrome seem to have a peculiar epileptic pattern mainly characterized by the occurrence of myoclonic seizures, the recognition of which is important in order to undertake an appropriate treatment.