Angelman syndrome (AS) is a rare neurodevelopment disorder (estimated incidence 1 in 12.000–20.0001) caused by disruption of the maternally-inherited UBE3A gene, most commonly due to a large deletion of the chromosome 15q11.2-q13 region, or to a pathogenic variant of the maternal copy of the UBE3A gene, paternal uniparental disomy, or imprinting defect2,3. The gene discussed is UBE3A; the disease is Angelman syndrome.