Profiling early socio-communicative development in five young girls with the preserved speech variant of Rett syndrome

► Various body movements, facial expressions, eye movements, and vocalizations were used to communicate. ► Non-verbal communicative forms dominated over verbal-communicative forms for most communicative functions. ► Early peculiarities in the speech-language domain during the first year of life became more prominent and evident during the second year of life. ► Socio-communicative deficits are present before regression and persist after this period. ► Assessing socio-communicative forms and functions at early age in children with RTT might essentially contribute to early detection.