Stranger Fear and Early Risk for Social Anxiety in Preschoolers with Fragile X Syndrome Contrasted to Autism Spectrum Disorder

This study investigated behavioral indicators of social fear in preschool boys with fragile X syndrome (FXS) with a low degree of autism spectrum disorder (ASD) symptoms (FXS-Low; n = 29), FXS with elevated ASD symptoms (FXS-High; n = 25), idiopathic ASD (iASD; n = 11), and typical development (TD; n = 36). Gaze avoidance, escape behaviors, and facial fear during a stranger approach were coded. Boys with elevated ASD symptoms displayed more...