A brain scan could potentially predict autism in babies before symptoms appear, researchers have said.
Scientists used MRI to study the brains of infants at high risk of the disorder – those who had older siblings with autism.
In 80% of the scans, researchers were able to predict correctly which children would be diagnosed with autism by the time they turned two.
Early diagnosis is key because it helps parents to understand why their babies may not be reaching certain developmental milestones.
And a study published in 2014 suggested that if treatment begins as early as the first six months of life, it can vastly improve a child's outcome.
But most children with autism do not get diagnosed until after the age of two.
Study leader Dr Joseph Piven, from the University of North Carolina, told CBS News: “It’s a time we’re talking about during the first year of life where the brain is most malleable.”
He went on to say: “[In brains with autism] we see an increased rate of growth in the outer surface of the brain - the folds and the sort of waviness of the surface that’s followed by an overgrowth of the brain in the second year.
“We haven’t had a way to detect the biomarkers of autism before the condition sets in and symptoms develop.
“Now we have very promising leads that suggest this may in fact be possible.”
There are around 700,000 people on the autism spectrum in the UK, which equates to more than 1 in 100, according to the National Autistic Society.