Implications of slow waves and shifting epileptiform discharges in Angelman syndrome

Objective: Angelman syndrome is a genetic syndrome resulted from a lack of UBE3A gene expression of the maternally inherited abnormalities of chromosome 15q11-q13. About 90% of patients with Angelman syndrome experience epilepsy and its distinctive electroencephalographic changes. Epilepsy predominates in childhood, but may persist in adulthood. The seizure types may be quite varied and sometimes difficult to control. Methods: We retrospectively reviewed and analyzed data of 18 patients with genetically and clinically confirmed Angelman syndrome at Asan Medical Center. Results: An analysis of 53 electroencephalography (EEG) records from 18 patients showed that diffuse slow-wave background patterns were significantly associated with uncontrolled periods of epilepsy. Moreover, epileptiform discharges tended to shift from posterior to anterior head regions over time after an initial normal pattern at a young age. Conclusions: Children with Angelman syndrome follow general developmental patterns, with specific patterns of EEG reflecting the maturational pattern of the brain and epileptic activity.