Movement Disorders and Syndromic Autism: A Systematic Review.

Only Angelman and Rett syndrome studies met the inclusion criteria, so the review cannot describe movement disorder prevalence in CHARGE, Cohen, Cornelia de Lange, Fragile X, or Tuberous Sclerosis Complex. Many included studies had moderate or high risk of bias because recruitment methods, sample representativeness, and response bias were often unclear. Most studies did not report reliability or validity for the movement disorder assessment, and only a few defined the movement disorder being measured. The review reports prevalence, not treatment effects, so it does not show that any therapy improves movement disorders in these syndromes. Sample sizes varied widely and some studies were small, which makes prevalence estimates unstable. Some prevalence estimates were based on people able to walk, so they may not apply to non-ambulatory patients.

Do not read these prevalence rates as evidence that a therapy for movement disorders works, or as evidence about all syndromes with syndromic autism. Only Angelman and Rett studies met inclusion criteria, and many studies had unclear recruitment, definitions, or assessment reliability.