SAN DIEGO – An international team of scientists led by UC San Diego has found what they believe is a way to accurately test for autism spectrum disorder in boys as young as 1-2 years old, the university announced Monday.
Their study, published in the current online issue of JAMA Psychiatry, said the scientists found a biomarker in blood in 75 percent or more of toddlers with ASD.
The degree of accuracy of the test is better than other behavioral and genetic screens for infants and toddlers with the condition, the researchers reported.
Current tests make it difficult to get a conclusive ASD diagnosis on a child until 4 years of age because the causes are complex and diverse, according to Eric Courchesne, the study’s principal investigator.
“A major challenge is the difficulty of accurately diagnosing ASD, which is very heterogeneous, at an early enough age to implement the most effective treatment,” Courchesne said.
Courchesne, the professor of neurosciences and director of the Autism Center of Excellence at the UC San Diego School of Medicine, said the biomarker was a measure of RNA expression levels in leukocytes — or white blood cells.
“Ideally, biomarkers come from (the) tissue affected, but in ASD this is the brain, which is obviously an inaccessible tissue,” Courchesne said.
“Peripheral blood of living ASD infants and toddlers is an important alternative, and obtaining blood samples is routine and safe and, thus, is a preferable and accessible tissue for identifying signatures of ASD that could be used in clinical screening and follow-up evaluations,” he said.
Courchesne said new studies point to autism beginning in the womb. His team analyzed the blood of 220 study participants divided into two groups. Each group had children with autism and a control group without the condition.
The accuracy of the blood testing was 83 percent in one group and 75 percent in the other.
Courchesne said this was a first step toward a possible means of diagnosing autism much earlier than can be done now, which would result in better intervention and treatment.
Boys were used in the study because they’re four times more likely to have autism. The next steps will be to find similar markers for toddler girls, and to refine the testing process, according to the professor.
Researchers at the Scripps Translational Sciences Institute, University of Cambridge and University of Cyprus assisted with the study, which was funded, in part, by the National Institutes of Health and UC San Diego.