Peripheral Expression of ADORA2A Is Increased and Is Correlated with Autism Spectrum Disorder Severity in a Sample of Turkish Children

Background: The aim of this study was to evaluate the peripheral expression of ADORA2A (Adenosine A2A receptor gene) in young subjects with autism spectrum disorder compared with healthy controls and its relationship with clinical characteristics. Method: This study included 93 children and adolescents with a diagnosis of autism spectrum disorder as the study group and 105 healthy age-and gender-matched controls. Blood samples were obtained from all participants, and a real-time quantitative polymerase chain reaction was performed. Parent-and clinician-rated assessment instruments were used to assess and rate the severity of autism spectrum disorder and other emotional/behavioral problems. Results: The mean age of the study group was 9.06 ± 3.57 and 86% were male (n = 83), whereas the mean age of the control group was 9.22 ± 3.86 and 86.7% were male (n = 91). We have found a higher level of peripheral expression of ADORA2A in children and adolescents with autism spectrum disorder compared with healthy controls (fold change = 1.33, P = .001). We also found a weak negative correlation with autism spectrum disorder severity (r = –0.216; P = .038) and stereotyped behaviors (r = –0.207, P = .046). Conclusion: ADORA2A genes may have a role in the pathophysiology of autism spectrum disorder. Further studies are needed to evaluate whether peripheral expression of ADORA2A genes may be among the biomarkers for diagnosing or measuring the severity of autism spectrum disorder.