Rare Daily Staff

Researchers at the University of Warwick and elsewhere say they have developed what they believe is a first-of-its-kind test that can diagnose children with autism spectrum disorders by identifying damaged proteins that are indicators of the condition in blood and urine.

Autism spectrum disorders are defined as developmental disorders mainly affecting social interaction and they can include a wide spectrum of behavioral problems. These include speech disturbances, repetitive and/or compulsive behavior, hyperactivity, anxiety, and difficulty to adapt to new environments, some with or without cognitive impairment.

Because there is a wide range of autism spectrum disorders, they can be difficult to diagnose, particularly in the early stages of development. The researchers say their tests could lead to earlier detection of the disorders and allow children with autism to receive appropriate treatment much earlier in their lives.

In a paper published in the journal Molecular Autism, the researchers identify biomarkers that can used for clinical diagnosis of the condition. They found a link between autism spectrum disorders and damage to proteins in blood plasma by oxidation and glycation—processes where reactive oxygen species and sugar molecules spontaneously modify proteins.

“We hope the tests will also reveal new causative factors,” said Naila Rabbani, Reader of Experimental Systems Biology at the University of Warwick and leader of the study. “With further testing we may reveal specific plasma and urinary profiles or fingerprints of compounds with damaging modifications. This may help us improve the diagnosis of ASD and point the way to new causes of ASD.”

The researchers found the most reliable of the tests they developed examined protein in blood plasma where, when tested, children with autism spectrum disorder were found to have higher levels of the oxidation marker dityrosine and certain sugar-modified compounds called “advanced glycation end products.” Genetic causes have been found in 30–35 percent of cases of autism spectrum disorders and the remaining 65 to 70 percent of cases are thought to be caused by a combination of environmental factors, multiple mutations, and rare genetic variants.

The research team believe that the new tests could reveal yet-to-be-identified causes of autism spectrum disorders. It also confirmed the belief that mutations of amino acid transporters are a genetic variant associated with autism spectrum disorders.

The Warwick team worked with collaborators at the University of Bologna, Italy, who recruited 38 children who were diagnosed as having with ASD (29 boys and nine girls) and a control group of 31 children (23 boys and eight girls) between the ages of five and 12. Blood and urine samples were taken from the children for analysis.

The University of Warwick team discovered that there were chemical differences between the two groups. Working with a further collaborator at the University of Birmingham, the changes in multiple compounds were combined using artificial intelligence algorithms techniques to develop an algorithm to distinguish between autism spectrum disorders and controls. The outcome was a diagnostic test that researchers said is better than any method currently available.

The next steps are to repeat the study with additional groups of children to confirm the good diagnostic performance. This will allow researchers to assess if the test can identify autism spectrum disorders at very early stages, and determine if treatments are working.

February 20, 2018
Photo: Naila Rabbani, Reader of Experimental Systems Biology at the University of Warwick and leader of the study