Table 1 Study inclusion and 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-Conference abstracts, unpublished manuscripts, expert opinions, editorials, comments, letters to the editor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