The Relationship Between Autism Spectrum Disorder and Purine Metabolism Enzyme Levels

Background and Aim: This study aimed to compare the serum levels of purine metabolism–related enzymes—xanthine oxidase (XO), 5′-nucleotidase (5′NT), and adenosine deaminase (ADA)—in children diagnosed with autism spectrum disorder (ASD) and healthy controls. By contributing to the understanding of the biochemical basis of ASD, the study sought to provide a scientific foundation for biomarker development. Materials and Methods: A total of 80 children were included in the study: 40 children diagnosed with ASD according to DSM-5 criteria and 40 healthy controls. Serum levels of 5′NT, ADA, and XO were analyzed using spectrophotometric methods. Results: XO levels were found to be significantly lower in the ASD group compared with the control group (p < 0.001). Although no statistically significant differences were observed between the groups in terms of ADA and 5′NT levels (p = 0.095 and p = 0.228, respectively), ADA activity tended to be lower and 5′NT activity higher in the ASD group. Additionally, no statistically significant correlations were detected among enzyme levels in either group (p > 0.05). Conclusion: Although not statistically significant for all parameters, the findings of higher 5′NT activity, lower ADA activity, and significantly reduced XO activity in the ASD group suggest a possible disturbance in purine metabolism and a potential accumulation of adenosine.