The diagnosis of Angelman syndrome (AS) is based on the clinical features, behavior, EEG findings, and genetic abnormalities. The physical, clinical and behavioral aspects appear to attributable to localized central nervous system (CNS) dysfunction of the ubiquitin ligase gene, UBE3A, located at 15q11.2. The features of AS frequently become apparent at 1-4 years of age, and the average age at diagnosis is 6 years
