An Investigation of the Sleep Macrostructure of Girls with Rett Syndrome

•Sleep investigation of a large sample of Rett Syndrome cases with MECP2 mutations.•A stratified analytic approach per genetic, clinical characteristics, and their severity.•Increased deep sleep and reduced REM-sleep are their phenotypic trait.•Sleep macrostructure abnormalities were salient with (psycho)motor impairments severity.•Possible poor sleep-on/off switching in Rett Syndrome cases with MECP2 mutations since embryogenesis.