Brain morphology, autistic traits, and polygenic risk for autism: A population-based neuroimaging study.
In typical 9- to 12-year-olds, more autistic traits predict slightly less brain folding and smaller surface areas, not just in kids with an ASD label.
01Research in Context
What this study did
The team scanned the brains of 9- to 12-year-old children in the general population.
They also scored each child’s level of autistic traits and calculated each child’s genetic risk for autism.
Then they asked: do kids with more traits or higher genetic risk show different brain shapes?
What they found
Children with more autistic traits had slightly less brain folding and smaller cortical surface areas.
These links showed up even in kids who did not have an ASD diagnosis.
Genetic risk alone did not explain the brain differences; trait level mattered more.
How this fits with other research
Lawer et al. (2009) found more folding in the right parietal lobe in twins with autism.
Lanfranchi et al. (2021) now finds less folding when traits are measured in non-diagnosed children.
The twin study looked at diagnosed pairs; the new study looks at trait spread in everyone.
Griffith et al. (2012) also saw thinner cortex in socially impaired children with ASD.
Silvia’s trait-based approach shows similar thinning appears across the whole population, not just the clinic group.
Burnham Riosa et al. (2023) links higher traits to poorer motor skills in adults.
Together, the papers say autistic traits track brain and behavior differences far beyond the diagnosis line.
Why it matters
You may see kids with social or motor quirks but no ASD label.
This work tells us their brains still show subtle ASD-linked patterns.
Keep trait checklists handy even for undiagnosed clients; they may guide your intervention targets and help you decide who needs a closer look.
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02At a glance
03Original abstract
Autism spectrum disorders (ASD) are associated with widespread brain alterations. Previous research in our group linked autistic traits with altered gyrification, but without pronounced differences in cortical thickness. Herein, we aim to replicate and extend these findings using a larger and older sample. Additionally, we examined whether (a) brain correlates of autistic traits were associated with polygenic risk scores (PRS) for ASD, and (b) autistic traits are related with brain morphological changes over time in a subset of children with longitudinal data available. The sample included 2400 children from the Generation R cohort. Autistic traits were measured using the Social Responsiveness Scale (SRS) at age 6 years. Gyrification, cortical thickness, surface area, and global morphological measures were obtained from high-resolution structural MRI scans at ages 9-to-12 years. We performed multiple linear regression analyses on a vertex-wise level. Corresponding regions of interest were tested for association with PRS. Results showed that autistic traits were related to (a) lower gyrification in the lateral occipital and the superior and inferior parietal lobes, (b) lower cortical thickness in the superior frontal region, and (c) lower surface area in inferior temporal and rostral middle frontal regions. PRS for ASD and longitudinal analyses showed significant associations that did not survive correction for multiple testing. Our findings support stability in the relationship between higher autistic symptoms and lower gyrification and smaller surface areas in school-aged children. These relationships remained when excluding ASD cases, providing neurobiological evidence for the extension of autistic traits into the general population. LAY SUMMARY: We found that school-aged children with higher levels of autistic traits had smaller total brain volume, cerebellum, cortical thickness, and surface area. Further, we also found differences in the folding patterns of the brain (gyrification). Overall, genetic susceptibility for autism spectrum disorders was not related to these brain regions suggesting that other factors could be involved in their origin. These results remained significant when excluding children with a diagnosis of ASD, providing support for the extension of the relationship between autistic traits and brain findings into the general population.
Autism research : official journal of the International Society for Autism Research, 2021 · doi:10.1002/aur.2576