Parents do not often realize that their child has autism until the age of two or three years old. But the condition, which hampers a child's normal development as well as affects his social and communication skills, appears to be already present long before the baby is born.

Researchers of a new study suggest that patchy changes in a baby's developing brain while still in the womb may be responsible for the development of autism spectrum disorder (ASD), a condition which affects about one in 88 children in the U.S.

In the study "Patches of Disorganization in the Neocortex of Children with Autism" published in the New England Journal of Medicine March 27, researchers examined the brain tissues of 22 dead children who were between the ages two and 15-years old. Half of the sampled brain tissues were from children with autism and the other half were from children without autism.

The researchers found a distinct characteristic in the brain tissues taken from ten of the 11 children with autism. They were dotted with patches of abnormal neurons in regions of the cortex that are involved in functions that children with autism have issues with. Kids who have autism often have trouble communicating and interacting with others.

"We identified discrete patches of disorganized cortex in the majority of postmortem samples obtained from young autistic children that we examined," the researchers reported. "These patches occurred in regions mediating the functions that are disturbed in autism: social, emotional, communication, and language functions."

The researchers said that because the patches do not fill the entire cortex, an infant's developing brain may still be rewired which means that early intervention may help children with autism.

"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 study author Eric Courchesne, professor of neurosciences at the University of California, San Diego.

Paul Wang, head of medical research at Autism Speaks said that the study underscores the importance of early identification and intervention.

"This also further reinforces the understanding that autism is caused by genetic factors, and the need to identify autism as early as possible, so that treatment can be started when they have the greatest potential," Wang said.