A review of co-occurrence of autism spectrum disorder and Tourette syndrome

•The comorbidities are: ASD/TS 4–5%, ASD/TD 9–12%, and AS/TS 20%.•ASD severity, proper diagnosis, sample size, and recruitment affect comorbidity.•There are many differences and similarities in the clinical phenotype of ASD and TS.•Differential diagnosis is essential for clinical management and intervention.•The distinction between tics and stereotypies hinders clinical practice.