Epilepsy and sleep disorders improve in adolescents and adults with Angelman syndrome: A multicenter study on 46 patients

Objective Actual knowledge on evolution of Angelman syndrome (AS) relies on questionnaire-based cohort studies, phone interviews, or small retrospective cohort studies focused on specific clinical–genetic features. These reports provide conflicting results. The aim of this study was to assess the long-term outcome of epilepsy, sleep disorders, and EEG in a vast series of AS subjects. Methods We collected patients with genetically confirmed AS, aged ≥ 14 years, followed in three tertiary epilepsy Centers or attending the meetings of the Italian Organization for AS (OrSA). Retrospective clinical and EEG data were retrieved from hospital archives or family documents. At index evaluation (IE) (last visit at tertiary Centers or single visit during OrSA meetings), caregivers were interviewed about anamnestic data and filled questionnaires on sleep disorders and daily-living skills. Patients underwent general and neurologic evaluation, and video-EEG recordings. All available EEGs were analyzed to compare evolution of spike–wave index (SWI) over the years. Results Forty-six subjects aged 14–45 years were included: 24 from tertiary Centers, 22 from OrSA meetings. During childhood, 42/46 (91.3%) had seizures, which improved over the years in all subjects. Among patients with epilepsy, 27(64%) became seizure-free at a median age of 10 years and 4 remained seizure-free even after antiepileptic withdrawal. During childhood, 39/46 (84.8%) had sleep disorders, which improved in 27/39 (69%) over the years. At IE, daily-living skills corresponded to age ≤ 1.6 years in 29/46 (63%). Electroencephalogram showed typical AS patterns in 35/46 (76.1%). In EEGs recorded from 10 patients, SWI was not significantly different between infancy/childhood and adolescence/adulthood. Conclusion Improvement of epilepsy or sleep disorders should not disregard the clinical suspicion of AS in adolescent or adult patients with suggestive features. Drug withdrawal might be considered in the management of epilepsy despite the persistence of epileptiform abnormalities.