Genetic and environmental overlap between cognitive atypicalities and autism spectrum disorder

Purpose: To examine the heritability of cognitive atypicalities and the genetic and environmental overlap between cognitive atypicalities and ASD.

Background: Cognitive atypicalities in central coherence (CC), executive function (EF) and theory of mind (ToM) are highly prevalent in ASD. These cognitive atypicalities could potentially be cognitive endophenotypes of ASD. However, there have been few twin studies into the heritability of these cognitive atypicalities, with no studies in ASD.

Method: Joint continuous-ordinal liability threshold model fitting was used to estimate the genetic and environmental contributions of the (co)variance of the best-estimate diagnosis (no ASD, broad spectrum or ASD) and each separate cognitive factor (local processing, executive functioning, theory of mind, global processing) in a sample of 127 ASD twin pairs and 80 control twin pairs.

Results: Global processing, EF and ToM were modestly associated with ASD. The local processing factor showed moderate genetic influence. All other cognitive factors showed low genetic influence. All cognitive factors showed substantial unique environmental influence. A modest shared genetic contribution between global processing and ASD.

Conclusion: This was the first study to examine the genetic overlap between cognition and ASD. There appears to be distinct aetiological influences on cognitive atypicalities and ASD. These bivariate genetic findings have implications for the biological basis of cognitive atypicalities and ASD.