Table 1.

Study inclusion and exclusion criteria

Category	Inclusion criteria	Exclusion criteria
Study design/publication type	-Observational studies (prospective, retrospective, cross-sectional, surveillance studies) -Meta-analysis or systematic reviews (to check the reference lists) -Human studies	-Randomized controlled trials (RCTs) -Narrative review -Conference abstracts, unpublished manuscripts, expert opinions, editorials, comments, letters to the editor -Animal studies -Genetic or molecular laboratory studies
Country	All countries/worldwide	No countries excluded
Study topic/subject	Diagnosed RTT syndrome	Other or unspecified conditions
Study population	General population (also stratified by, e.g., gender, age, sex, geographical area, etc.)	Other populations
Outcomes of interest	Prevalence/incidence/proportion of diagnosed RTT	Other outcomes

RCTs Randomized controlled trials, RTT Rett syndrome