UBE3A and Angelman syndrome: Angelman syndrome (AS), a severe neurodevelopmental disorder caused by loss of the maternal allele of E3 ubiquitin ligase UBE3A, is characterized by a constellation of symptoms including recurrent seizures (>90% of individuals), motor impairment, sleep disruption, intellectual disability, and absence of speech (Williams et al., 2010; Thibert et al., 2013; Buiting et al., 2016).