Each syndrome was characterized by specific sleep disturbances such as bedtime resistance and night awakenings in Angelman and SYNGAP1 diseases, laughing, teeth grinding, and screaming in Rett syndrome and parasomnias and daytime sleepiness in SYNGAP1‐related disorders.15, 16, 17, 30. The gene discussed is SYNGAP1; the disease is atypical Rett syndrome.