Despite considerable progress in characterizing the early signs of autism spectrum disorder (ASD), more remains to be learned about how symptoms emerge in the first year of life. Parents with a new baby who already had at least one biological child diagnosed with ASD (high-risk) or no family history of ASD (low-risk) completed two measures when…

This study examined the potential of the short form of the Quantitative Checklist for Autism in Toddlers (Q-CHAT-10) to identify autism spectrum disorder (ASD) in a high-risk sibling cohort. High-risk (HR; siblings of children diagnosed with ASD) and low-risk (LR; no family history of ASD) toddlers were assessed prospectively at 18 and 24 months…

Social-emotional behavior in autism spectrum disorder (ASD) was examined among high-risk (HR; siblings of children diagnosed with ASD) and low-risk (LR; no family history of ASD) toddlers. Caregivers completed the Infant-Toddler Social Emotional Assessment (ITSEA) at 18 months, and blind diagnostic assessment for ASD was conducted at 36 months.…

This study assessed sensory processing differences between 24-month infants at high-risk of autism spectrum disorder (ASD), each with an older sibling with ASD, and low-risk infants with no family history of ASD. Sensory processing differences were assessed using the Infant/Toddler Sensory Profile, a parent-reported measure. Groups were compared…

It has been proposed that females at risk for autism are protected in some way, so that only those with the greatest genetic liability are affected. Consequently, affected male siblings of females with autism should be more impaired than affected male siblings of male probands. One hundred and ninety-four (194) families with a single child with…

Sex differences were examined in 3-year-olds with autism spectrum disorders (ASD) ascertained from a high-risk cohort, and high- and low-risk comparison groups. Participants included 319 high-risk siblings and 129 low-risk controls. Eighty-five siblings were diagnosed with ASD, including 57 of 176 boys (32.4%) and 28 of 143 girls (19.6%), implying…

This study examined motor behaviors in a longitudinal cohort of infant siblings of children with autism. Stereotypic movements and postures occurring during standardized observational assessments at 12 and 18 months were coded from videotapes. Participants included eight infant siblings later diagnosed with autism spectrum disorder (ASD), a random…

The objective of this review is to clarify the role of matching in family genetic studies of autism as a way of defining endophenotypes for linkage analysis. The concept of a confounding variable is reviewed and the importance of considering these in family studies of three endophenotypes in autism are considered: cognitive/language impairments,…