In the single-choice question: "Which genetic background for Angelman syndrome was identified during the diagnosis?", out of five possible answers: 80% of caregivers (n = 56) indicated a deletion (of the maternal region containing UBE3A), 12.9% a mutation of the UBE3A gene, 4.3% paternal uniparental disomy (UPD), and 2.8% an imprinting defect. The gene discussed is UBE3A; the disease is Angelman syndrome.