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Sex differences in repetitive stereotyped behaviors in autism: Implications for genetic liability

Authors

  • Peter Szatmari,

    Corresponding author
    1. Offord Centre for Child Studies, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
    • Offord Centre for Child Studies, Hamilton, Ontario, Canada L8N 3Z5.
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  • Xiao-Qing Liu,

    1. Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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  • Jeremy Goldberg,

    1. Offord Centre for Child Studies, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
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  • Lonnie Zwaigenbaum,

    1. Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
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  • Andrew D. Paterson,

    1. Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
    2. Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
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  • Marc Woodbury-Smith,

    1. Offord Centre for Child Studies, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
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  • Stelios Georgiades,

    1. Offord Centre for Child Studies, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
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  • Eric Duku,

    1. Offord Centre for Child Studies, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
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  • Ann Thompson

    1. Offord Centre for Child Studies, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
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  • How to Cite this Article: Szatmari P, Liu X-Q, Goldberg J, Zwaigenbaum L, Paterson AD, Woodbury-Smith M, Georgiades S, Duku E, Thompson A. 2012. Sex Differences in Repetitive Stereotyped Behaviors in Autism: Implications for Genetic Liability. Am J Med Genet Part B 159B:5–12.

Abstract

The implications of the well known sex differences in the prevalence of autism spectrum disorder (ASD) are not well understood. The aim of this paper was to investigate whether these differences might be associated with differences in genetic liability. Individuals with ASD (970 families, 2,028 individuals) were recruited as part of the Autism Genome Project (AGP). The families were differentiated into families containing a female (either female–female or male–female) and those with only males. If the sex with the lower prevalence is associated with a greater genetic liability necessary to cross sex-specific thresholds, the males from female containing families should be more severely affected than males from male only families. Affected subjects from the different types of families with ASD were sampled and compared on the social reciprocity and repetitive behavior scores from the Autism Diagnostic Interview-Revised (ADI-R). In general, females had lower repetitive behavior scores than males. More importantly, males from female containing families had higher repetitive behavior scores than males from male–male families. No such differences were apparent on the social reciprocity scores. These results support the hypothesis of a multiple threshold model of genetic liability of ASD with females having a higher liability for affectation status, at least on the repetitive behavior dimension of the disorder. These data also support the dissociation of the different phenotypic dimensions of ASD in terms of its genetic architecture. The implications of these results for linkage and association studies are discussed. © 2011 Wiley Periodicals, Inc.

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