Familiality of Quantitative Autism Traits

Background: Autistic traits exist along a continuum that extends into social functioning in the general population, and they aggregate in the family members of children with autism spectrum disorder (ASD). Quantitative measures are therefore essential when investigating the patterns of familiality of these traits. Prior studies have suggested differential inheritance patterns of autistic traits that depend on the cognitive level of the child with ASD as well as the family type. Objective: Our goal was to examine the family patterns of quantitative autism traits (QAT) in a group of simplex autism families of high-functioning children with ASD. Method: We used the Social Responsiveness Scale (SRS) to evaluate QAT in 47 ASD families and 46 control families. SRS assessments (parental/spousal evaluations) were collected for the children with ASD, their siblings, and their parents as well as for the control children and their parents. Results The SRS was able to distinguish individuals with ASD from the control children and from their unaffected siblings. Significant group differences were also found when comparing the fathers of ASD families to control fathers and when comparing the brothers of individuals with ASD to control boys, with male members of ASD families having higher SRS scores. Gender differences were observed in the group of siblings of children with ASD and the group of parents of children with ASD, with males having higher scores than females. In ASD families, a positive trend between child and father QAT was found, whereas mothers’ scores were not associated with child outcomes. By contrast, in control families, mothers’ QAT correlated more strongly with child QAT. Conclusions: Autistic traits aggregate in the fathers and brothers of children with ASD in simplex autism families. The QAT levels of the family members should be taken into consideration when planning the rehabilitation of the child or adolescent with ASD and when designing family interventions.