Cognitive Profiles and Autism Symptoms in Comorbid Down Syndrome and Autism Spectrum Disorder

: Objective: The prevalence of comorbid autism spectrum disorder (ASD) in children with Down syndrome (DS) is estimated to be around 16%. This study aims to fill gaps in the literature by describing developmental and behavioral phenotypes in this group relative to those with DS or ASD in isolation. Methods: Participants included 173 children ( M age = 73 months) with ASD, DS, or DS + ASD. Two 3 × 2 repeated-measures analyses of variance were...