Novel metabolic biomarkers related to sulfur-dependent detoxification pathways in autistic patients of Saudi Arabia

20 males autistic children aged 3-15 years and 20 age and gender matching healthy children as control group were included in this study. Levels of reduced glutathione (GSH), total (GSH+GSSG), glutathione status (GSH/GSSG), glutathione reductase (GR), glutathione- s-transferase (GST), thioredoxin (Trx), thioredoxin reductase (TrxR) and peroxidoxins (Prxs I and III) were determined.Reduced glutathione, total glutathione, GSH/GSSG and activity levels of GST were significantly lower, GR shows non-significant differences, while, Trx, TrxR and both Prx I and III recorded a remarkably higher values in autistics compared to control subjects.The impaired glutathione status together with the elevated Trx and TrxR and the remarkable over expression of both Prx I and Prx III, could be used as diagnostic biomarkers of autism.Autism spectrum disorders (ASDs) are prevalent neurodevelopmental disorders that, based on a recent survey, affect not less than 1 in 150 children born [1]. Lastly, in Saudi Arabia (population under 23 million) there were 42 500 confirmed cases of autism in 2002, and many more cases remain undiagnosed [2]. ASD diagnoses are characterized by impairments in social relatedness and communication, repetitive behaviours', abnormal movement patterns, and sensory dysfunction [3]. Further, common co-morbidity conditions often associated with an ASD diagnosis include gastrointestinal disease and dysbiosis [4], autoimmune disease [5], and mental retardation [6].Several lines of evidence support an association of oxidative stress with ASD in at least some cases. First, there is evidence of reduced endogenous antioxidant capacity. Specifically, reduced enzymatic activities of glutathione peroxidase (GPX) [6-8], superoxide dismutase (SOD) [7,8] and catalase [9,10], and reduced levels of total glutathione (GSH), GSH/GSSG and cysteine [11] have been reported. Levels of exogenous antioxidants were also reportedly reduced in autism, including vitamin C, vitamin E and vitamin