Brief report: Plasma oxytocin is lower in children with Asperger syndrome and associated with autistic trait attention to detail

Aim: Autism spectrum disorders (ASD) are described as a continuum of severity gradient of autistic symptoms diffusing through particular ASD diagnoses, however the biological correlates among individuals with the different ASD diagnoses slightly or considerably differ. Oxytocin (OT) has been implicated to play an important role in autism etiology. Lower OT levels have been previously found in children with infantile autism, however in a group of high-functioning autistic subjects, no differences have been shown compared to controls. Moreover, whereas the opposite patterns of OT associations with social measures have been found in children with infantile autism compared to healthy children, no associations have been found in individuals with high-functioning autism. We aimed to find out the plasma OT differences between separate group of children with Asperger syndrome (AS) and healthy children and the associations of OT with particular autistic traits in a group of children with AS. Methods: We included 9 children (m = 6, f = 3) with AS at the age 9 to 12 years and 9 ageand gender-matched controls. OT levels were analyzed by ELISA method. Autistic traits in children with AS were evaluated by Autism Spectrum Quotient (AQ), child and adolescent versions. Results: Children with AS had significantly lower plasma OT levels compared to healthy children. We found the significant negative correlation of OT level and AQ Attention to detail area score. Conclusion: In spite of the lower OT level in children with AS, which is also previously found in children with infantile autism, the pattern of OT associations with autistic traits more resembles the pattern in non-autistic population. Our preliminary results support the hypothesis of continuum within the ASD particular diagnoses in the terms of biological correlates.