Potential biomarker for autism found

By John Murphy, MDLinx
Published May 5, 2016

Key Takeaways

Researchers have identified a first-of-its-kind blood biomarker that predicts autism spectrum disorder (ASD) with 66% accuracy—and over 80% accuracy if combined with other tests. If validated, the biomarker could provide an earlier diagnosis and even help measure the severity of ASD, according to a study published in the journal Scientific Reports.

Diagnosing autism currently relies on developmental screening and behavioral evaluations. So, most children aren’t diagnosed until communication and social disabilities become apparent, about age 4 on average.

But an earlier diagnosis—as from a blood biomarker—would allow for earlier, targeted intervention, which could lessen the burden of ASD in the children and their families, the researchers noted.

“Numerous investigators have long sought a biomarker for ASD,” said senior author Dwight German, PhD, Professor of Psychiatry at the University of Texas Southwestern Medical Center, in Dallas, TX.

“The blood biomarker reported here along with others we are testing can represent a useful test with over 80% accuracy in identifying ASD,” he said.

Separate studies have identified widespread immune system abnormalities in children with autism. So for this study, Dr. German and colleagues sought to discover antibodies related to ASD in the blood of boys with the disorder. Using highly complex libraries of peptoids, the researchers screened the compounds for those that preferentially bind to IgG in 74 boys with ASD. They did the same screening in 60 similar boys without ASD.

When the researchers analyzed their results, they found that the boys with ASD had significantly reduced levels of a serum IgG1 antibody. To narrow this down, they further analyzed 25 peptoid compounds that bound to IgG1 and identified one, ASD1, which had an accuracy of 66%, a sensitivity of 78%, and a specificity of 51% in predicting a diagnosis of ASD.

When the researchers combined ASD1 binding with measurements of thyroid stimulating hormone levels in both groups of boys, the combination was 73% accurate at diagnosis. This could serve as a useful blood biomarker panel for ASD, they concluded.

In addition, peptoid binding to IgG1 may be useful as a severity marker to allow further characterization of ASD in children, the researchers noted.

But first, more testing—including analysis of blood samples from girls with ASD—is needed to further validate the findings, Dr. German said. Girls made up a small ratio of the study group, and the biomarker did not correlate as strongly with ASD diagnosis as with boys.

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