title: Brief Report: Relationship between non-verbal IQ and gender in autism.
abstract: It has been proposed that females at risk for autism are protected in some way, so that only those with the greatest genetic liability are affected. Consequently, affected male siblings of females with autism should be more impaired than affected male siblings of male probands. One hundred and ninety-four (194) families with a single child with autism (simplex, SPX) and 154 families with more than one child with autism (multiplex, MPX) were examined on measures of severity, including non-verbal IQ. Among SPX families, girls had lower IQ than boys, but no such differences were seen among MPX families. Similarly, the affected brothers of girls with autism were no different from affected brothers of male probands. These data suggest that MPX and SPX families differ with respect to the relationship between gender and IQ.
authors.affiliation: Department of Family Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Ryan
authors.initials: R
authors.lastname: Banach
authors.forename: Ann
authors.initials: A
authors.lastname: Thompson
authors.forename: Peter
authors.initials: P
authors.lastname: Szatmari
authors.forename: Jeremy
authors.initials: J
authors.lastname: Goldberg
authors.forename: Lawrence
authors.initials: L
authors.lastname: Tuff
authors.forename: Lonnie
authors.initials: L
authors.lastname: Zwaigenbaum
authors.forename: William
authors.initials: W
authors.lastname: Mahoney
mesh_terms: D001321:Autistic Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D002648:Child; D002675:Child, Preschool; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007360:Intelligence / Q000235:genetics; D008297:Male; D010641:Phenotype; D012744:Sex Ratio; D014888:Wechsler Scales