Air Pollution, Genetics Increase Autism Risk

Statistics show that approximately one in 88 children in the United States alone suffer from an autism spectrum disorder (ASD), a lifelong neurodevelopmental disorder that's marked by an individuals inability to comprehend social situations as well as his or her increase of repetitive behaviors.  Yet a recent study suggests that while genetics play an important role regarding the problem, many questions still remain regarding environmental factors that could play a role in the probability of the disease.

"Although gene-environment interactions are widely believed to contribute to autism risk, this is the first demonstration of a specific interaction between a well-established genetic risk factor and an environmental factor that independently contribute to autism risk," said Daniel B. Campbell, Ph.D., assistant professor of psychiatry and the behavioral sciences at the Keck School of Medicine of USC and the study's senior author, via a press release. "The MET gene variant has been associated with autism in multiple studies, controls expression of MET protein in both the brain and the immune system, and predicts altered brain structure and function. It will be important to replicate this finding and to determine the mechanisms by which these genetic and environmental factors interact to increase the risk for autism."

Campbell and Volk's research teams examined 408 children between the ages of 2 and 5 from the Childhood Autism Risks for Genetics and the Environment Study, a population-based, case-control study of preschool children of California. From the sample, they found that 252 met the criteria for an autism spectrum disorder, with many living in unfavorable living condition that may have increased the risk of the disease. For instance, they found that air pollution exposure was determined based on many past residences of the children and their mothers, as well as local traffic-related sources and regional air quality measures.

Previous findings provided through their research have shown distinct associations between autism and air pollution exposure with a variant in the MET gene. 

The current study suggests that air pollution exposure and the genetic variant may interact to augment the risk of an ASD.
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More information regarding the study will be available via the 2014 edition of Epidemiology.