Angelman syndrome in three biological siblings: Focusing on the neuropsychiatric domain

Angelman syndrome (AS) is a neurogenetic disorder that usually presents with delayed motor milestones, ataxic gait, mental retardation, language disorder, seizures, sleep disturbances, characteristic facial features, and happy demeanor. The genetic abnormality of AS has been located on chromosome 15q11-q13. The AS gene(s) is exclusively expressed from the maternal chromosome. Loss of the maternally contributed AS region can occur by deletion, paternal uniparental disomy, imprinting defects, mutation of the ubiquitin-protein ligase (UBE3A) gene, and by yet unidentified mechanisms. Deletion of maternal chromosome accounts for most of the cases of AS with imprinting accounting for 2%-5% of cases. In imprinting inheritance, offsprings of carrier mothers are theoretically at 50% risk of having AS. Familial occurrence of AS has been reported. Here, we highlighted the rare incident of AS in three biological siblings and their neuropsychiatric manifestations as well as different psychosocial aspects.