Angelman syndrome (AS) is a neurodevelopmental disorder characterized by severe developmental delay, intellectual disability, speech impairment, gait ataxia, epileptic seizures, and exuberant behavior with happy demeanor. The majority of patients have poor quality of life and cause great burden to family and society. It is known that AS is caused by four genotypes which have different clinical manifestations. In this article, the recent advances in pathogenesis, the relationship between genotype and symptoms, and the treatment strategies of AS will be reviewed.