Autism spectrum disorder (ASD) is a condition that impacts cognition, behavior, and social interaction.
The Centers for Disease Control and Prevention (CDC) estimate that 1 in 68 children have ASD.
Given its developmental nature, ASD may have an early onset, but it typically takes a while for the first symptoms to appear. As such, early diagnosis is not usually possible.
Therefore, a chemistry-based diagnosis test for the early detection of ASD may be crucial, enabling children to receive the care that they need much earlier on. Until now, no such test was available.
But an international team of researchers — led by Dr. Naila Rabbani, a reader of experimental systems biology at the University of Warwick — believes that it has designed tests that can accurately detect ASD-related protein changes in the blood and urine.
The findings were published in the journal Molecular Autism.
Tests yield 92 percent accuracy
Dr. Rabbani and her team collected and analyzed blood and urine samples from 38 children aged between 5 and 12 who had been diagnosed with ASD, as well as from 31 children who had not.
The researchers found chemical differences between children with ASD and neurotypical children — that is, children without ASD.
Specifically, the scientists found an association between ASD and damage to some proteins found in the blood's plasma, or the fluid that carries white and red blood cells.
Of the several blood and urine tests that the scientists developed, the most accurate one found that children with ASD had higher levels of a compound called dityrosine and another class of compounds called advanced glycation end-products (AGEs).
Dityrosine is a marker of oxidation damage, and AGEs are the result of glycation, which is a process wherein sugars combine with amino acids, the "building blocks of proteins."
Dr. Rabbani and colleagues then fed this information into a computer algorithm, which resulted in a diagnostic test with 92 percent sensitivity. Sensitivity refers to the ability of a medical test to accurately identify people who have a disease.
Will the test lead to earlier ASD diagnosis?
Dr. Rabbani comments on the significance of the findings, saying, "Our discovery could lead to earlier diagnosis and intervention. We hope the tests will also reveal new causative factors."
"With further testing we may reveal specific plasma and urinary profiles or 'fingerprints' of compounds with damaging modifications."
Dr. Naila Rabbani
"This may help us improve the diagnosis of ASD," she adds, "and point the way to new causes of ASD."
But Dr. Max Davie — an assistant officer for health promotion at the Royal College of Paediatrics and Child Health in the U.K. — has expressed skepticism about such a test, saying, "This is a promising area, however this is a very long way indeed from a 'test for autism.'"
He adds, "The analysis was derived from children whose ages averaged 7–8, so there is no data to indicate that very young children will have the same metabolic pattern and that the results found would be reproducible in infants."
"While we applaud the arrival of this interesting area of research," says Dr. Davie, "it is important that it is not adopted with too much enthusiasm." He cautions that applying the test to a large population may produce a large number of false positives, causing unnecessary worry.