New research on autism states that the condition most likely develops during pregnancy and environmental factors play a crucial role.
Researchers at the York University found that abnormal levels of lipid molecules in the brain affect the contact between two key neural pathways in early prenatal brain development, which can lead to autism.
They explained that the exposure to pollution or to the chemicals in some cosmetics and common over-the-counter medication affect the lipid levels. "We have found that the abnormal level of a lipid molecule called Prostaglandin E2 in the brain can affect the function of Wnt proteins. It is important because this can change the course of early embryonic development," Professor Dorota Crawford in the Faculty of Health and a member of the York Autism Alliance Research Group said in a news release.
"Using real-time imaging microscopy, we determined that higher levels of PGE2 can change Wnt-dependent behavior of neural stem cells by increasing cell migration or proliferation. As a result, this could affect how the brain is organized and wired. Moreover, we found that an elevated level of PGE2 can increase expression of Wnt-regulated genes - Ctnnb1, Ptgs2, Ccnd1, and Mmp9. Interestingly, all these genes have been previously implicated in various autism studies," lead researcher and York U doctoral student Christine Wong explained.
Autism is more common in boys than girls and is known to be a disorder of brain development. The symptoms range from mild to severe and include repetitive behavior, deficits in social interaction and impaired language skills. The statistics released by the Centers for Disease Control and Prevention from 2010 state that 1 in 68 children in the United States has the condition.
"The statistics are alarming. It's 30 per cent higher than the previous estimate of 1 in 88 children, up from only two years earlier. Perhaps we can no longer attribute this rise in autism incidence to better diagnostic tools or awareness of autism," Crawford said.
The researchers say their study threw up molecular evidence of the environment interrupting early brain development leading to autism.
Crawford explained that genes do not experience major changes in evolution and even if the genetic factors are considered as contributors to the condition, environmental factors such as inadequate dietary supplement of fatty acids, exposures to infections, various chemicals or drugs can change gene expression and lead to autism.