The world's biggest study of children with autism has found the first biologically different types of the disorder, a move likened to the landmark discovery of specific types of cancer about five decades ago.
Early findings from the study, which started in 2006 and is known as the Autism Phenome Project, will be released at a major autism conference starting in Perth today.
Results from the University of California's MIND Institute research are based on brain tests, DNA and immune systems of more than 300 children with autism.
MRI scans of the brain have shown a link between autism and the amygdala, the almond-shaped mass of nuclei located deep within the temporal lobe of the brain that helps control a person's mental and emotional state.
The research has also revealed abnormalities in the immune systems of children with autism.
Experts believe being able to clinically diagnose sub-types of autism is the key to preventing and treating the neurodevelopmental condition that affects one in 160 Australian children. It has no cure.
Until now, child health professionals have been limited in how they define types of autism and mostly rely on behavioural checklists.
University of California professor of psychiatry and neuroscience David Amaral said there were probably many subtypes of autism.
Identifying and studying them was a key to a cure.
"When you put an apple, an orange and a banana in a blender, you get this homogenous mixture and at the moment we have a blender of children with autism when we need to get back to the apple, the orange and banana to see the differences," Dr Amaral said.
"In our study, we're starting to see clear subsets of kids and we're getting to the point where we're not that far away from being able to document them."
More than 1300 experts from around the world are attending the three-day Asia Pacific Autism Conference, which starts today at the Burswood conference centre and is hosted by the Autism Association of WA and sponsored by the State Government.
Association chief executive Joan McKenna Kerr said demand for services for children with autism was now greater than the demand for services for children with cerebral palsy, Down syndrome or sensory disabilities.