A twin study investigating the genetic and environmental aetiologies of parent, teacher and child ratings of autistic-like traits and their overlap.
ABSTRACT In the present study we investigated phenotypic agreement between informants (parent, teacher and child self-report) on ratings of autistic-like traits and compared the genetic and environmental aetiologies of the informants' ratings and of their covariance. Parents and teachers of >2,500 pairs from a community twin sample completed an abbreviated Childhood Asperger Syndrome Test (CAST). The twins also completed an adapted self-report version of the CAST. Structural equation model-fitting was carried out. Correlations between raters were significant but moderate (0.16-0.33). The magnitude of heritability estimates of autistic-like traits varied across raters, being highest for parent-rated autistic-like traits (82-87%) and more modest for child self-reported autistic-like traits (36-47%). Genetic overlap was significant but moderate across all raters. These findings are discussed in relation to population screening for autism and future genetic research.
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ABSTRACT: In recent years, several twin studies adopted a dimensional approach to Autism Spectrum Disorders (ASD) and estimated the contribution of genetic and environmental influences to variation in autistic traits. However, no study was performed on adults over 18 years of age and all but two studies were based on parent or teacher ratings. Also, the genetic and environmental contributions to the interplay between autistic traits and adult personality dimensions have not been investigated.Comprehensive Psychiatry 12/2014; 58. DOI:10.1016/j.comppsych.2014.12.018 · 2.26 Impact Factor
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ABSTRACT: Autism shows a high degree of comorbidity with anxiety disorders. Adolescence is a time of increased stress and vulnerability to internalising problems. This study addresses for the first time the degree of genetic and environmental overlap between autistic traits (total measure and subscales) and internalising traits in a community-based adolescent twin sample. Parents of 12-14-year-old twins (N = 3,232 pairs; 3,460 males, 3,004 females) reported on the twins' internalising and autistic traits. Autistic trait subscales were created using principal component analysis. Bivariate twin model-fitting was conducted. Autistic and internalising traits correlated moderately (r = 0.30). Genetic influences on individual traits were substantial but genetic overlap between traits was moderate (genetic correlation: males = 0.30, females = 0.12). Shared environmental influences were low for internalising traits and moderate for autistic traits, and showed considerable overlap (shared environmental correlation: males = 0.53, females = 1). Nonshared environmental influences were moderate for internalising traits and low for autistic traits and showed low overlap. A multiple component solution was found for autistic traits and of the derived subscales, autistic-like 'Social Unease' showed the most phenotypic and genetic overlap with internalising traits.Journal of Abnormal Child Psychology 08/2013; 42(4). DOI:10.1007/s10802-013-9796-y · 3.09 Impact Factor
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ABSTRACT: Autistic traits-social impairment, communication impairment, and restricted and repetitive behaviors and interests-are heritable in the general population. Previous analyses have consistently reported limited genetic and environmental overlap between autistic trait domains in samples assessed in middle childhood. Here we extend this research to parent-report data for 12-year-olds. Data from 5,944 pairs in the Twins Early Development Study were analyzed to explore the domain-specific heritability and degree of shared genetic and environmental influences across different autistic traits in the general population and among individuals scoring in the top 5% of each domain. Sex differences in the etiological estimates were also tested in these analyses. Autistic traits were moderately to highly heritable (0.58-0.88) at age 12. Bivariate genetic correlations in the full sample (0.18-0.40) and the extremes (0.24-0.67), as well as even lower unique environmental correlations, all suggested considerable fractionation of genetic and environmental influences across autistic trait domains, in line with previous findings.Behavior Genetics 09/2011; 42(2):245-55. DOI:10.1007/s10519-011-9500-3 · 2.84 Impact Factor