Scientists have discovered a new evidence to prove that autism is a kind of disorder that begins in the womb. Symptoms of autism could be caused by patchy changes in the developing brain long before birth takes place.

US scientists came across this significant finding after analyzing post-mortem brain tissue of 22 children between two and 15 years of age with and without autism spectrum disorder (ASD). The findings of the study, published in the New England Journal of Medicine, have highlighted the importance of early identification and treatment, said a University of California team.

The study will also help in gaining better insight into the brain to better the plight of children with autism.

The study saw usage of genetic markers to figure out as to how the outermost part of the brain, the cortex, wired up and layers were formed. About 90% of the children were detected with autism compared to about 10% of children without.

The abnormalities were found in brain regions that were responsible for social and emotional communication, and language. These changes started to occur in the brain long before birth.

Patchy nature may provide an explanation for how some children with autism are able to improve if provided with treatment early enough, said the researchers from the University of California, San Diego and the Allen Institute for Brain Science in Seattle.

"The finding that these defects occur in patches rather than across the entirety of cortex gives hope as well as insight about the nature of autism", said Prof Eric Courchesne, a neuroscientist at the University of California San Diego.

Carol Povey, Director of the National Autistic Society Centre for Autism, said the findings of the study must not be trivialized because they throw light on a complex and often misunderstood disability. The right support can make a huge difference to autism.