Over the last decade, autism research has been primarily focused on finding genes that may "cause" autism. However, little information exists on gene-environment interactions that may increase risk for autism.
Valerie Hu, Ph.D., professor of biochemistry and molecular medicine at the George Washington University School of Medicine and Health Sciences, was awarded $435K from the National Institute of Environmental Health Sciences to study how certain environmental factors affect the gene retinoic acid-related orphan receptor-alpha (RORA), which has been shown to be an important regulator of multiple genes of neurological significance in those with autism.
"You can have a genetic predisposition for lung cancer, but if you've never smoked, you may never develop cancer. On the other hand, you could smoke like a chimney and live a long life - if you're not genetically susceptible, you may never have cancer," said Hu. "Like cancers, where genes and environment play a role in susceptibility, diseases of the brain, like autism, can be viewed in terms of genes and environmental interactions."
Hu and colleagues recently reported that RORA regulates more than 2,500 genes; over 400 of these genes are considered to be autism candidate genes. Previous research by Hu's laboratory also found that male and female sex hormones regulate RORA in opposite directions, suggesting that this may play a role in the sex bias in autism. Hu believes that endocrine disrupting compounds (EDCs), many of which are environmental pollutants that interfere with hormonal signaling, may interfere with the normal expression of RORA, leading to increased risk for autism.
Hu will study how RORA's expression changes as a result of exposure to various EDCs found in the environment, such as BPA found in plastics and atrazine found in weed killer. Such chemicals have been shown to interfere with the endocrine system at very low levels. She will then examine how exposure to EDCs impact neuronal processes.
Hu anticipates that the information gained through these studies will lead to public health policies to protect the public against exposure to environmental agents that may promote developmental disorders and neurological dysfunction, which may also account for the increasing prevalence of autism, as well as stimulate the development of treatment protocols to counteract the effects of exposure to these compounds.
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