A new blood test for autism can diagnose children who previously had not even detected the most developed screens for the set of disorders.
There are already a handful of tests for the disorder, which affects one in 45 American children, but there are also many unknowns of autism that make it difficult for doctors to diagnose it with absolute certainty.
Behavior and an older diagnostic test can trap more than 90 percent of autism cases, but they are not widely used, and the new test detects about 17 percent of children who belong to a subset of the spectrum that could have overlooked previously.
Researchers at the University of California, Davis, developed their new detection method through the largest study on autism spectrum disorders to date.
A new blood test for autism spectrum disorder can detect genetic and environmental signs of the condition in the blood of a small subset of people in the spectrum
The race is underway to create a fail-safe test for autism spectrum disorder (ADS)
Until recently, there has not been a biological test for children on the spectrum.
Children have been previously diagnosed based on their altered behaviors, which may not be evident until children are between two and four years old.
And families often have to wait to see a specialist for a more in-depth evaluation, which must begin within three months of the recommendation, but may take longer.
But in February, scientists released a blood test that had destroyed them with its accuracy.
And since then, a number of similar detection methods have appeared.
Now, scientists at the University of California at Davis have identified a group of blood metabolites that could help detect some children with ASD.
The new panel of biomarkers could accelerate the diagnosis of autism, since about 17 percent of children with autism are identified with the metabolic blood test. This could accelerate children who have intensive behavioral therapy at a younger age.
Dr. David Amaral, of the MIND Davis Institute of the University of California, said: "With this panel of alterations in amino acid metabolism, we can detect approximately 17 percent of children with ASD.
"This is the first of the panels with luck that will identify other subsets of children with autism."
The findings were based on the largest metabolic ASD study ever attempted: the Childhood Autism Metabolome Project (CAMP).
The CAMP researchers believed that the answer lies in the metabolome: the molecules that remain after the larger molecules have been broken down (metabolized).
Metabolomics has the advantage of controlling the genetic and environmental contributions to the development of autism.
So far, about 65 genes related to autism have been identified, and there may be more to discover, not to mention the environmental factors at play.
"Autism is not a single entity, it's a diverse spectrum," says Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, and the father of a daughter on that spectrum.
"It's hard to imagine how there could be a single blood test," he says.
Then the new test can fit into a larger constellation of screens for autism.
Dr. Amaral, professor of psychiatry and behavioral sciences, explained: "When you get to metabolomics, you're seeing how the body works, not just the genes it has."
& # 39; It is unlikely that a single marker will detect all autism & # 39;
But the new test could detect cases of autism that others would lose.
"This document demonstrates that alterations in metabolic profiles can detect considerable subsets of people with autism," said Dr. Amaral.
"The hope is that we can generate a panel of biomarkers that will detect a large proportion of people at risk.
"In addition, this approach highlights the metabolic pathways that can be targeted by the intervention."
The study collected blood samples from 1,100 children between 18 months and 4 years of age, of whom two thirds were diagnosed with ASD.
The researchers compared blood metabolites, specifically amino acids, in 516 children with ASD and 164 children who show typical development.
They found that 17 percent of children with ASD had unique concentrations of specific amino acids (metabopic) in their blood.
Although it may seem small, it is actually quite significant.
ASD encompasses a complex series of symptoms, and no one expected to find a single group of markers that would diagnose all subsets.
Dr. Amaral said that it is expected to create a series of metabolomic assays that cover all variations.
He said: "The long-term vision is that, once we have been able to analyze all the CAMP data, we would have a series of panels.
& # 39; Each of these could detect a subset of children with autism.
"Ultimately, metabolomics may be able to identify the majority of children with autism.
"In addition to allowing an earlier diagnosis, this work could also help generate specific interventions for specific groups of ASD."
Dr. Amaral points out phenylketonuria (PKU) as a possible template.
PKU is a rare disease in which the amino acid phenylalanine accumulates, causing brain damage; however, relatively small dietary adjustments can make a big difference.
He concluded: "With just a simple dietary modification, a child can go from being deeply disabled to one that lives a reasonably normal life
That's the hope with autism too.
"I am optimistic that this is not an exception, there will be other panels that can detect other groups of children with ASD."
The study was published in the journal Biological Psychiatry.