Abstract
Autism spectrum disorder (ASD) is a common neurodevelopmental condition, and infant siblings of children with ASD are at a higher risk of developing autistic traits or an ASD diagnosis, when compared to those with typically developing siblings. Reports of differences in brain anatomy and function in high‐risk infants which predict later autistic behaviors are emerging, but although cerebellar and subcortical brain regions have been frequently implicated in ASD, no high‐risk study has examined these regions. Therefore, in this study, we compared regional MRI volumes across the whole brain in 4–6‐month‐old infants with (high‐risk, n = 24) and without (low‐risk, n = 26) a sibling with ASD. Within the high‐risk group, we also examined whether any regional differences observed were associated with autistic behaviors at 36 months. We found that high‐risk infants had significantly larger cerebellar and subcortical volumes at 4–6‐months of age, relative to low‐risk infants; and that larger volumes in high‐risk infants were linked to more repetitive behaviors at 36 months. Our preliminary observations require replication in longitudinal studies of larger samples. If correct, they suggest that the early subcortex and cerebellum volumes may be predictive biomarkers for childhood repetitive behaviors. Autism Res 2019, 12: 614–627. © 2019 The Authors. Autism Research published by International Society for Autism Research published byWiley Periodicals, Inc.Lay SummaryIndividuals with a family history of autism spectrum disorder (ASD) are at risk of ASD and related developmental difficulties. This study revealed that 4–6‐month‐old infants at high‐risk of ASD have larger cerebellum and subcortical volumes than low‐risk infants, and that larger volumes in high‐risk infants are associated with more repetitive behaviors in childhood.
Highlights
Autism spectrum disorder (ASD) is a common heterogeneous neurodevelopmental condition, characterized by difficulties in reciprocal social communication and social interaction, restricted and repetitive patterns of behavior, and atypical sensory responses (American Psychiatric Association, 2013)
Increasing evidence suggests that infants at high-risk of ASD have early differences in brain structure and function at 6 months, which are associated with subsequent development of ASD symptoms
In regions where the high-risk group had shown significant differences in brain volumes at 4–6 months, we examined the association of these early volumes with ASD outcome measures at 36 months
Summary
Autism spectrum disorder (ASD) is a common heterogeneous neurodevelopmental condition, characterized by difficulties in reciprocal social communication and social interaction, restricted and repetitive patterns of behavior, and atypical sensory responses (American Psychiatric Association, 2013). Increasing (albeit preliminary) evidence suggests that infants at high-risk of ASD have early differences in brain structure and function at 6 months, which are associated with subsequent development of ASD symptoms. It is still unclear whether anatomical differences can be identified at younger ages and/or in other brain regions. Cerebellar abnormalities are among the most frequently reported findings in ASD literature (Becker & Stoodley, 2013; Fatemi et al, 2012; Rogers et al, 2013), and subcortical brain regions have been linked to ASD in older cohorts (Estes et al, 2011; Langen et al, 2014; Langen, Durston, Staal, Palmen, & van Engeland, 2007; Stanfield et al, 2008), no study has yet explored whether the development of these regions is altered in very young infants at risk of ASD
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