Melbourne: Scientists have for the first time discovered two biologically different strains of autism in a breakthrough which they claim could lead to the development of effective treatments for the condition.
The findings, which are compared with the discovery of different forms of cancer in the 1960s, raised hope that the communication, socialisation and other difficulties that autistic children experience can be tackled more easily and earlier.
Researchers at the University of California Davis's MIND Institute in Sacramento studied the brain growth, genetic make-up and environmental exposure of about 350 children aged between two and 2.5 years.
One group of children -- all boys -- were found to have enlarged brains and most had regressed into autism after 18 months of age; while another group had immune systems that were not functioning properly, The Australian reported.
Psychiatry professor David Amaral, who led the MIND Institute's Autism Phenome Project, said the findings could lead to more individualised treatment.
"The ultimate goal is when a child comes into the clinic, rather than saying you just have autism, to be able to say you have autism type A, or type B, or type C," Dr Amaral said.
"And then based on that description, we would know whether there is a different treatment profile that we should recommend to the families.
"As an example, if a child has an immune form of autism, it may be that what we want to do is manipulate their immune system rather than trying something else that may be related to synaptic functions in the brain."
The researchers presented their study at the Asia Pacific Autism Conference in Perth on Thursday.

Families were currently presented with a vast array of treatments without necessarily knowing which worked.
"But if we can give them more information about what exactly is the causal process for their child's autism, then we can focus in on that and hopefully have a more productive intervention," Amaral said.
He predicted there would be many more biological subtypes of autism identified just as there were many forms of cancer.
"If we were trying to cure all cancer at the same time, it would be hopeless," he said.
"The same is true for autism. My guess is that there just isn't going to be a single diagnostic marker for autism - there's going to be a whole panel."
Bruce Tonge, emeritus psychiatry professor at Monash University, agreed that many subtypes of autism were likely to emerge.
"It has been for some time known that at least for some children with autism, their brains grow too rapidly in the first couple of years of life and then plateau out," Tonge said.
"So further refinement of that knowledge will be important. Currently, a number of people are also looking for other possible environmental contributing factors, and the interaction between the environment and a person's immune system might be an interesting possibility there."