Abstract
The marked heterogeneity of autism spectrum disorders is a challenge for research into biomarkers of these disorders. The present study aimed to assess the association of the thioredoxin (TRX) system and vasopressin with autism in children. Thirty-five autistic children were recruited with thirty-one healthy controls children matched for age and gender. Total antioxidant capacity (TAC), vasopressin, peroxiredoxin (PRDX1, PRDX3), phox domain-containing protein kinase-like protein, and TRX1 levels were measured in plasma and mercury and lead levels were measured in red blood cells. Children with autism had significantly lower levels of PRDX1 and TRX1 and significantly higher levels of lead and mercury compared with controls. Significantly higher levels of vasopressin were also observed in more severe cases of autism. Receiver operating characteristics analysis demonstrated satisfactory specificity and sensitivity of TAC, PRDX1, PRDX3, and TRX1 for the diagnosis of autism. The optimal cut-off value for plasma TRX1 levels, as an indicator of autism, was 10.6 ng/mL. Significant positive correlations existed between TRX system components, lead, and mercury. A negative correlation was found between vasopressin and TRX1, but positive correlations were found between vasopressin and mercury and lead. In conclusion, TAC, PRDX1, PRDX3, and TRX1 may be useful biomarkers for the diagnosis of autism in Saudi populations. Vasopressin-resistance in autistic patients may be due to an increased oxidative burden.