Face individual identity recognition: a potential endophenotype in autism

Abstract

Background: Face individual identity recognition skill is heritable and independent of intellectual ability. It can be measured early in development, in individuals with intellectual disability and is translatable to animal models. Difficulties in face individual identity recognition are present in autistic individuals and their family members and are possibly linked to oxytocin polymorphisms in families with an autistic child. While we know that developmental prosopagnosia (i.e., impaired face identity recognition) occurs in 2-3% of the general population, no prosopagnosia prevalence estimate is available for autism. Furthermore, an autism within-group approach has not been used to characterize impaired face memory and investigate its possible links to social and communication difficulties. Methods: We estimated prevalence of prosopagnosia in 80 autistic adults with no intellectual disability, investigated its cognitive characteristics and links to autism symptoms’ severity, personality traits and mental state understanding from the eye region by using standardized tests and questionnaires. Results: More than one third of autistic participants showed prosopagnosia. Their face memory skill was not associated to their symptom’s severity, empathy, alexithymia or general intelligence. Face identity recognition was instead linked to mental state recognition only in autistic individuals who had prosopagnosia, and this relationship did not depend on participants’ basic face perception skills. Importantly, we found that autistic participants were not aware of their face memory skills. Conclusions: Impaired facial individual identity recognition is found in a large subgroup of individuals on the autism spectrum and is associated with difficulties in mental state understanding from the eye region. Testing for face memory could, in the future, potentially be used to stratify autistic individuals in genetically meaningful and oxytocinrelevant subgroups and be translatable to autism animal models.