title: The Autism-Spectrum Quotient in Siblings of People With Autism.
abstract: This study measures the distribution of autistic traits, using the autism-spectrum quotient (AQ), in siblings of individuals with autism spectrum conditions (ASC). Total AQ scores, along with AQ subscales, were collected from child, adolescent and adult controls, siblings, and volunteers with ASC using one of the three age-appropriate versions of the instrument: the AQ (adult self-report), the AQ-adolescent and AQ-child (both parent-reports). We examined the effect of Group (case, sibling and control) and AQ version (adult, adolescent and adult) on total and subscale scores. In addition, we tested for sex differences in all groups and on all versions. We found that in male and female adults, AQ scores in siblings fell between cases and controls (cases > siblings > controls). In children and adolescents, female siblings also scored higher than control females (female cases > female siblings > female controls), but there was no difference between male siblings and controls (male cases > male siblings = male controls). An investigation of subscale scores revealed that male siblings only differed from controls on the "Communication" subscale (male cases > male siblings > male controls), while female siblings differed from controls on all subscales except "Imagination" (female cases > female siblings > female controls). This study confirms the broader autism phenotype in siblings, and reveals this is modulated by sex and AQ version. Autism Res 2017, 10: 289-297. © 2016 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research.
authors.affiliation: Cambridge Intellectual and Developmental Disabilities Research Group, Department of Psychiatry, University of Cambridge, Cambridge, UK.
authors.forename: Emily
authors.initials: E
authors.lastname: Ruzich
authors.affiliation: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK.
authors.forename: Carrie
authors.initials: C
authors.lastname: Allison
authors.affiliation: NIHR CLAHRC for the East of England, Cambridge, UK.
authors.forename: Paula
authors.initials: P
authors.lastname: Smith
authors.affiliation: Cambridgeshire and Peterborough NHS Foundation Trust, Peterborough, UK.
authors.forename: Howard
authors.initials: H
authors.lastname: Ring
authors.affiliation: CLASS Clinic, Cambridgeshire and Peterborough NHS Foundation Trust, Peterborough, UK.
authors.forename: Bonnie
authors.initials: B
authors.lastname: Auyeung
authors.affiliation: Psychology Department, University of Edinburgh, Edinburgh, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Baron-Cohen
mesh_terms: D000293:Adolescent; D000328:Adult; D000067877:Autism Spectrum Disorder / Q000175:diagnosis* / Q000523:psychology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D010641:Phenotype; D057566:Self Report; D012737:Sex Factors; D035781:Siblings / Q000523:psychology*
keywords: autism; autism-spectrum quotient; autistic traits; sex differences; siblings