Signs of autism are evident in children as young as 6 months but take time to unfold, a development researchers said could lead to opportunities to intervene before the disorder makes its full mark.

The finding comes from research on 92 infants considered at high-risk for autism because each had an older sibling with the developmental disorder.

For the study, researchers at the University of North Carolina looked at brain scans from the children to identify differences between those with and without autism.

At 6 months, the pathways that connect regions of the brain were more developed in children who were later diagnosed with autism than those who were typically developing, the researchers found. But by 2-years-old, the opposite was true, they reported online in the American Journal of Psychiatry on Friday.

“It’s a promising finding,” said Jason Wolff of the UNC Carolina Institute for Developmental Disabilities and lead author of the study. “At this point, it’s a preliminary albeit great first step towards thinking about developing a biomarker for risk in advance of our current ability to diagnose autism.”

Ultimately, Wolff said, the new knowledge may allow researchers to “interrupt” the development of autism through early intervention.

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