Speaker 2: Gianluca Esposito, Italy

s | 35 Abstract Due to familial factors, younger siblings of children with Autism Spectrum Disorder (ASD) are at an increased risk for developing the disorder1,2. Although behavioral symptoms of ASD typically emerge during a child’s second year,3 recent work on younger siblings demonstrates that prodromal features of ASD are present already within the first months of life. These features include atypical attention toward stimuli relevant to social engagement, such as faces and speech sounds.4,5 Similar deficits were observed in clinic-referred toddlers suggesting continuity of social attention impairments in ASD from prodromal to early syndromal stages.6,7 This presentation will review: (1) the methodological underpinnings of prospective high-risk sibling studies and findings on patterns of autism onset in infancy, and (2) experimental studies on endoand exogenous attention to multimodal social stimuli conducted during prodromal and early syndromal stages of the disorder.Due to familial factors, younger siblings of children with Autism Spectrum Disorder (ASD) are at an increased risk for developing the disorder1,2. Although behavioral symptoms of ASD typically emerge during a child’s second year,3 recent work on younger siblings demonstrates that prodromal features of ASD are present already within the first months of life. These features include atypical attention toward stimuli relevant to social engagement, such as faces and speech sounds.4,5 Similar deficits were observed in clinic-referred toddlers suggesting continuity of social attention impairments in ASD from prodromal to early syndromal stages.6,7 This presentation will review: (1) the methodological underpinnings of prospective high-risk sibling studies and findings on patterns of autism onset in infancy, and (2) experimental studies on endoand exogenous attention to multimodal social stimuli conducted during prodromal and early syndromal stages of the disorder.