Autism spectrum disorders (ASD) are highly heritable and first degree relatives (especially fathers) of autistic probands have been shown to often manifest a set of subthreshold autistic features. It is not known, however, the clinical significance of this subthreshold autism spectrum.

– to evaluate the prevalence of a subthreshold autism spectrum respectively in fathers and mothers of children with ASD;

– to describe clinical correlates of parents with and without a subthreshold autism spectrum respectively.

36 fathers and 39 mothers of preschoolers with ASD were administered the autism-spectrum quotient (AQ), the adult autism subthreshold spectrum (AdAS spectrum), the trauma and loss spectrum (TALS), the SCID-5 and the social and occupational functioning assessment scale (SOFAS).

Fathers and mothers did not differ for both AQ and AdAS spectrum total and subscale scores. Overall, 13 parents (17.3%) scored higher than 45 on the AdAS spectrum, as indicative of the presence of a subthreshold autism spectrum. This group showed greater prevalence of mood, anxiety and feeding/eating disorders, greater utilization of antidepressants and higher scores on the TALS and the SOFAS than the group scoring lower than 45 (all P < 0.05).

Fathers and mothers of children with ASD show autistic traits in equal measure. The presence of a subthreshold autism spectrum is associated to greater prevalence of mood, anxiety and feeding/eating disorders, to greater susceptibility to traumatic events and to lower levels of functioning.

The authors have not supplied their declaration of competing interest.