The world's biggest DNA scan for autism has uncovered new genetic changes linked to the condition which US researchers say could help doctors diagnose children earlier and deliver improved treatment.
The results, published in the journal Nature by the Autism Genome Project led by the Mount Sinai school of medicine in New York, could speed the development of the first genetic test for the condition, which affects up to one in 160 Australians.
A detailed study of almost 1000 children with autism and their parents found sections of the DNA were either missing or duplicated in people with the condition.
Clusters of the new genetic variations were rare in healthy children but 20 per cent more common in those with autism. An unexpected finding was that some of the genetic changes found in the children were not carried by the parents, suggesting that tiny genetic errors might occur during the formation of the parents' eggs and sperm and then pass on to the child.
Mount Sinai psychiatry and genetics professor Joseph Buxbaum said the landmark study showed an overlap between autism susceptibility genes and genes previously linked to other intellectual disabilities.
"As we continue to uncover genetic mutations that can cause autism, we are gaining further insights that will ultimately lead to earlier diagnosis and better treatments," he said.
The study also confirmed some children carry "private" genetic mutations unique to them which contribute to their susceptibility.
The results coincided yesterday with the release of a study by Melbourne researchers who found that special brain markers for autism could be seen in a scan known as an electroencephalogram.
Swinburne University said the scan recorded activity in the brain prompted by visual images and could become a new tool to diagnose autism.
In Fremantle, LEARN Foundation for Autism chief executive Mandy Mason said early diagnosis was crucial in improving the outcome for children such as five-year-old Cameron Smith, who has been having early intervention therapy for two years.
"It's really important that children are diagnosed before the age of three so they don't fall too far behind and are given communication skills so they can access the world", she said.
"Untreated autism at the age of two or three becomes a severe disability by age eight because children regress and don't have the social skills they need."