Gene-environment interplay in reading performance

Genetic factors are known to play a role in shaping reading abilities and their underlyingcognitive processes. However, understanding how genetic and environmental factorsinteract to influence reading outcomes remains largely unknown. By evaluating the interplaybetween genetic and environmental influences on reading performance, this study aims toprovide insights into the complex mechanisms underlying reading abilities. To this aim, weleveraged the Adolescent Brain Cognitive Development dataset, considering socioeconomicindicators including household income and parental education, along with linguisticcharacteristics such as bilingualism and the child’s first language (L1). We operationalizedgenetic influences as polygenic scores (PGS), which aggregate genetic risk across multipleloci associated with reading-relevant traits (word reading, dyslexia, cognitive performance,and educational attainment). First, we establish the individual associations between selectedenvironmental and genetic predictors for reading, observing that all except L1 are significantpredictors of reading, with a similar range of variance explained by the two types ofpredictors. Next, we confirm an additive effect, as the PGS remain significant afteradjustment for the environmental effects, although the effects of PGSEducationalAttainment andPGSCognitivePerformance are attenuated, confirming a partial gene-environment correlation. This isfurther supported by analyzing direct and genetic effects in a subset of siblings. Next,potential interactions between the PGS and these environmental variables are considered.Finally, we evaluate the combined contribution of the four PGS through a multiPGS analysis,which improves the predictive power of the individual PGS analyses, explaining up to 10% ofvariance in reading performance (adjusted R2). Sensitivity analyses with other cognitiveoutcomes (vocabulary and fluid intelligence) reveal that the observed pattern is specific toreading. Our study highlights the important and interrelated roles of both environmental andgenetic factors in shaping reading abilities.