Heritability of quantitative autism spectrum traits in adults: A family-based study.
Autism trait scores in adults are strongly heritable, making them reliable tools for genetic risk assessment.
01Research in Context
What this study did
Researchers studied 19 autism traits in the adults from the families.
They used self-reports, informant reports, and direct tests.
The team asked: how much of these traits run in families?
What they found
Every trait showed strong heritability.
Scores ranged from a large share to a large share genetic influence.
Self-report and informant-report measures shared the highest heritability.
How this fits with other research
Day-Watkins et al. (2014) found fathers' traits predict child autism better than mothers' traits. This new study extends that work by showing all family members' trait scores are genetically linked.
Xia et al. (2020) hunted for specific autism genes but found none that reached significance. Palka Bayard de Volo et al. (2021) explains why: autism traits are highly heritable, but each gene adds only tiny effects.
Chen et al. (2020) used these same trait measures to predict suicide risk in kids. Palka Bayard de Volo et al. (2021) validates these measures as genetically meaningful, strengthening their use in clinical prediction.
Why it matters
You can now trust quantitative autism trait scores as valid measures. These scores capture real genetic differences, not just random variation. When you see elevated trait scores in parents, know these reflect genuine genetic risk that may appear in their children. This helps explain why autism runs in families beyond just diagnosis.
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02At a glance
03Original abstract
Autism spectrum disorder (ASD) comprises a multi-dimensional set of quantitative behavioral traits expressed along a continuum in autistic and neurotypical individuals. ASD diagnosis-a dichotomous trait-is known to be highly heritable and has been used as the phenotype for most ASD genetic studies. But less is known about the heritability of autism spectrum quantitative traits, especially in adults, an important prerequisite for gene discovery. We sought to measure the heritability of many autism-relevant quantitative traits in adults high in autism spectrum traits and their extended family members. Among adults high in autism spectrum traits (n = 158) and their extended family members (n = 245), we calculated univariate and bivariate heritability estimates for 19 autism spectrum traits across several behavioral domains. We found nearly all tested autism spectrum quantitative traits to be significantly heritable (h2 = 0.24-0.79), including overall ASD traits, restricted repetitive behaviors, broader autism phenotype traits, social anxiety, and executive functioning. The degree of shared heritability varied based on method and specificity of the assessment measure. We found high shared heritability for the self-report measures and for most of the informant-report measures, with little shared heritability among performance-based cognition tasks. These findings suggest that many autism spectrum quantitative traits would be good, feasible candidates for future genetics studies, allowing for an increase in the power of autism gene discovery. Our findings suggest that the degree of shared heritability between traits depends on the assessment method (self-report vs. informant-report vs. performance-based tasks), as well as trait-specificity. LAY SUMMARY: We found that the scores from questionnaires and tasks measuring different types of behaviors and abilities related to autism spectrum disorder (ASD) were heritable (strongly influenced by gene variants passed down through a family) among autistic adults and their family members. These findings mean that these scores can be used in future studies interested in identifying specific genes and gene variants that are associated with different behaviors and abilities related with ASD.
Autism research : official journal of the International Society for Autism Research, 2021 · doi:10.1002/aur.2417