Autism test could unlock much earlier diagnosis

A test for autism could allow far earlier diagnosis in children, British researchers claim, having discovered what appear to be chemical indicators in blood and urine samples. Autistic Spectrum Disorder (ASD) is believed to impact approximately 1 in 100 people, but with its broad range of symptoms can be difficult to correctly identify thus delaying possible treatment.

Indeed, while autism is often referred to as a singular condition, in reality it's an umbrella term that encompasses a wide array of disorders. According to the DSM-5, the latest iteration of the diagnostic tool used by the American Psychiatric Association, ASD covers everything from Asperger syndrome through lesser-known conditions like childhood disintegrative disorder. Each has different combinations of presentation, which can include problems in social interaction, struggling with communication, and repetitive behaviors.

Symptoms generally begin to display – or at least be identified – by the time the child is 1-2 years old. Nonetheless, settling on a diagnosis can take considerably longer. Researchers led by a team at the University of Warwick, however, have identified the basis for what they describe as a test that flags the "fingerprints" of ASD much earlier than traditional methods.

Their discovery was of a link between ASD and proteins in blood plasma which had been damaged by oxidation and glycation. In children with ASD, proteins in their blood plasma were found to have higher levels of the oxidation marker dityrosine (DT), along with certain sugar-modified compounds called "advanced glycation endproducts," or AGEs. In addition, they tested – and confirmed – previous suggestions that amino acid transporter mutations are a genetic variant associated with ASD.

The system included using artificial intelligence to create an algorithm that can distinguish between ASD and non-ASD samples. It also opens the door to much greater understanding of the disorder. Indeed, the researchers suggest that while a combination of genetic causes, environmental factors, and rare genetic variants are known to be causes of autism, the tests could reveal other causes we currently don't know about.

"Our discovery could lead to earlier diagnosis and intervention," project lead Dr Naila Rabbani of the University of Warwick said of the research. "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. This may help us improve the diagnosis of ASD and point the way to new causes of ASD."

Actually treating the disorder has proved controversial. While there is no known cure for autism, behavioral-based therapies and special education have been shown to give those on the ASD spectrum better skills at managing in daily life. The efficacy of such has been shown to improve the earlier such therapies are begun, something which could clearly benefit from earlier diagnosis.

The research findings have been published in a paper today, "Advanced glycation endproducts, dityrosine, and arginine transporter dysfunction in autism—a source of biomarkers for clinical diagnosis," in the journal Molecular Autism. Nonetheless, we're still some way from an actual test that could be applied to children.