Table 4 Eligibility criteria to screen full-text for inclusion/exclusion in the meta-analysis

Study reports the number of participants with the genetic syndrome who met a clinical cut-off for that syndrome (not an associated syndrome e.g., Fragile X-associated tremor/ataxia syndrome)

Study does not report the number of participants who met a clinical cut-off for that syndrome

Study reports on a unique sample (or a potentially overlapping sample, but the proportion of overlap cannot be readily determined)

Study reports on exactly the same sample as reported in a previous study

Participants recruited without any specific bias (e.g., not recruited for a drug trial for a sleep disorder)

Participants were recruited due to an existing sleep disorder

Study reports the number of participants with the genetic syndrome who had a sleep disorder or difficulty

It is not possible to determine the number of participants with the sleep disorder or difficulty included in the study

Data in the study were extractable for meta-analysis (e.g., number of participants presenting sleep disorder)

Data in the study were not extractable for meta-analysis (e.g., mean questionnaire scores)

Sleep was reported as a naturally occurring phenomenon, not through manipulation

Sleep was reported as an adverse event of treatment or following experimental manipulation

Study reports the number of participants experiencing a sleep disorder, not solely the number taking medication to treat a sleep disorder

Study reports only the number of participants who were taking medication for sleep disorder

Study reports prevalence of sleep disorder or difficulty

Study reports only sleep times or architecture