Beyond Autism: A Baby Siblings Research Consortium Study of High-risk Children at Three Years of Age

This study is the first large-scale examination of ASD behavioral characteristics and developmental functioning in high-risk (HR), non-autistic 3-year-olds with siblings on the spectrum. 79% of HR children were either no different from low-risk children (LR; no known ASD family history) with respect to ASD behavioral severity and developmental functioning, or were developmentally on target with high levels of ASD-related behaviors. 21% of HR children with no ASD diagnosis had an "early manifestation" of a broad autism phenotype: high levels of ASD-related behaviors and/or low levels of verbal and nonverbal functioning. The authors highlight the importance of developmental surveillance and intervention for this HR subset.