Although children with learning disabilities frequently manifest comorbid reading and mathematics deficits, the cause of this comorbidity is unknown. To assess the extent to which comorbidity between reading and mathematics deficits is due to genetic and environmental influences, we conducted a twin study of reading and mathematics performance. Data from 148 identical and 111 fraternal twin pairs in which at least one member of the pair had a reading disability were subjected to a cross-concordance analysis and also fitted to a bivariate extension of the basic multiple regression model for the analysis of selected twin data. Results of these analyses suggest that genetic and shared-environmental influences both contribute to the observed covariance between reading and mathematics deficits.
Although results obtained from recent twin and adoption studies suggest that individual differences in mathematics performance are due in part to heritable influences, no genetic analysis of mathematics disability (MD) has been previously reported. In this article we present data from the first twin sample ascertained for mathematics deficits (40 identical and 23 same-sex fraternal twin pairs in which at least one member had MD). When mathematics performance data from these twin pairs were subjected to a multiple regression analysis, evidence for a significant genetic etiology was obtained. However, tests for the differential etiology of MD as a function of reading performance level were nonsignificant. Results of this first twin study of MD indicate that the condition is significantly heritable, but data from additional twin pairs will be required to test hypotheses of differential etiology more rigorously.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.