Researchers led by the University of Warwick have developed blood and urine tests which show diagnostic sensitivity and specificity for autism spectrum disorder (ASD). The first-of-a-kind tests could lead to earlier diagnosis of ASD and consequently, earlier intervention, they say.
Working with collaborators at the University of Bologna in Italy and the University of Birmingham, the Warwick team collected blood and urine samples from 38 children who were diagnosed with ASD and a control group of 31 healthy children, between the ages of 5 and 12 years. Plasma protein glycation, oxidation, and nitration adducts and amino acid metabolome in plasma and urine were determined. Machine learning methods were then employed to explore combinations for ASD diagnosis.
They found that children with ASD had increased advanced glycation endproducts (AGEs), Nε-carboxymethyllysine (CML) and Nω-carboxymethylarginine (CMA), and increased oxidation damage marker, dityrosine (DT), in plasma protein, with respect to healthy children. Children with ASD also had increased CMA-free adduct in plasma ultrafiltrate and increased urinary excretion of oxidation free adducts, alpha-aminoadipic semialdehyde and glutamic semialdehyde. From study of renal handling of amino acids, they found that children with ASD had decreased renal clearance of arginine and CMA with respect to healthy children.
Algorithms to discriminate between children with ASD and healthy children gave strong diagnostic performance with features: plasma protein AGEs-CML, CMA- and 3-deoxyglucosone derived hydroimidazolone, and oxidative damage marker, DT. The sensitivity, specificity, and receiver operating characteristic area-under-the-curve were 92%, 84%, and 0.94, respectively.
The next steps are to repeat the study in additional groups of children to confirm the good diagnostic performance and to assess if the test can identify ASD at very early stages.
