Developmental path between language and autistic-like impairments: a twin study
Version of Record online: 8 JAN 2008
Copyright © 2008 John Wiley & Sons, Ltd.
Infant and Child Development
Volume 17, Issue 2, pages 121–136, March/April 2008
How to Cite
Dworzynski, K., Ronald, A., Hayiou-Thomas, M. E., McEwan, F., Happé, F., Bolton, P. and Plomin, R. (2008), Developmental path between language and autistic-like impairments: a twin study. Inf. Child Develop., 17: 121–136. doi: 10.1002/icd.536
- Issue online: 26 MAR 2008
- Version of Record online: 8 JAN 2008
- National Alliance for Autism Research
- MRC program. Grant Number: G0500079
- autism spectrum disorders;
- early language development
Autism spectrum disorders (ASDs) are diagnosed when individuals show impairments in three behavioural domains: communication, social interactions, and repetitive, restrictive behaviours and interests (RRBIs). Recent data suggest that these three sets of behaviours are genetically heterogeneous. Early language delay is strongly associated with ASD, but the basis for this association and the relationship with individual sub-domains of ASD has not been systematically investigated. In the present study, data came from a population-based twin sample with language development data at 2–4 years, measured by the MacArthur Communicative Development Inventory (MCDI), and data at 8 years using the Childhood Asperger Syndrome Test (CAST). For the total CAST and the three subscales at 8 years, approximately 300 same-sex twin pairs were selected as showing extreme autistic-like traits (ALTs), defined here as pairs in which at least one member of the twin pair scored in the highest 5% of the distribution. Phenotypic analyses indicated that children showing extreme social and communication ALTs (but not the RRBI subscale) at 8 years were below average in language development at 2–4 years. A regression model for selected twin data suggested that genetic influences account for this overlap, but that these effects are only in part mediated by genes that are shared between language and extreme autistic traits. Copyright © 2008 John Wiley & Sons, Ltd.