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Spring 2011

Genetics Plays the Dominant Role in Autism

03/14/2011

VS-Spring2011-AutismWhile researchers are still not certain what causes autism spectrum disorder (ASD), experts believe the root may be an interaction of genetic-risk factors with environmental factors that leads to autism.

“We believe that about 70 percent of autism is caused by genetics and the other 30 percent by environment,” says Daniel Geschwind, M.D., Ph.D., director of the UCLA Center for Autism Research and Treatment. “Genetics can alter a person’s response to environment, so in some cases it may be necessary to have a genetic predisposition for an environmental trigger to cause autism.”

“One of the problems with unraveling the mystery of autism is that it is defined by behavioral observation rather than by biological testing at this point,” Dr. Geschwind says. “There is no biological model for how autism occurs,” he adds. “There is currently no one study we can do to point to autism because it’s not based on a brain abnormality. But we can use a genetic toolbox to identify susceptibility factors that may eventually lead to clues about biological pathways to the disorder.”

Dr. Geschwind and his team recently collaborated with 30 research institutions across the country to identify a new gene variant that is common in the general population but occurs about 20 percent more often in children with autism. They also have shown that other autism-related genes are most active in key regions of the brain that support language, speech and interpreting social behavior. The findings suggest that autism genes play a critical role in shaping the developing brain. Overall, genetic factors increase the risk for autism 10–20 fold over the general population.

“We’ve found dozens of genes related to autism; some have known functions, while others don’t,” he explains. “But we know there are many causes, most likely hundreds of different mutations, that are helping us paint a picture about what’s happening with autism.” The result, he says, is that researchers are now able to identify a genetic mutation in at least 10–20 percent of autistic children who come to the UCLA clinic, compared to just 1 percent 10 years ago. While there is still no single genetic test or cure for autism, there are certain types of genetic tests that should be performed in all patients with autism, so parents and prospective parents can arm themselves with knowledge about the disorder, Dr. Geschwind says.

VS-Spring2011-Genetics Autism“Parents who are concerned about autism should include genetic counselors in their family planning, particularly if they already have a child with ASD,” he notes. In families in which one child has ASD, the risk of having a second child with the disorder is approximately 10–20 percent, or one in 10 to one in five, which is at least 10 times greater than the risk for the general population.

“In addition, early diagnosis and intervention is critical. We have excellent behavioral and cognitive interventions that can really make a long-term difference in the lives of children with neurodevelopmental disabilities,” Dr. Geschwind says. “We need to get these interventions out into the community to treat autistic children early, when they’re likely to benefit the most.”

For more information about autism research and treatment at UCLA, go to: www.semel.ucla.edu/autism





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