Autism's Possible Genetic Cause Comes to Light in New Study

DNA insertions and deletions may contribute to autism, researchers say.

ByABC News
June 9, 2010, 12:29 PM

June 9, 2010 -- Researchers believe they have found some of the edge pieces in the jigsaw puzzle that is autism spectrum disorder.

A new study has found that duplicated and deleted pieces of DNA in a number of different genes play a role in the development of autism, said study co-author Rita M. Cantor, a professor of genetics and psychiatry at the David Geffen School of Medicine at UCLA.

Advocacy groups are optimistic that the findings could lead to new treatments for the disorder. A number of autism researchers said the discovery could one day lead to earlier diagnosis and treatment. Although some cautioned that it's too early to say how big a step forward the gene findings are, they clearly show the important role of genetics in autism.

At the center of the issue may be stretches of DNA, called copy number variants, or CNVs, that appear to be more common in children with autism than in others.

"Children with autism have 20 percent more CNVs that disrupt genes," said Cantor.

The CNVs were found most often in genes that affect brain development than in other pathways that have nothing to do with the brain, she said.

And while these CNVs are common, they can vary greatly from person to person.

"They're not all seen in the same place, but they are ubiquitous," Cantor said.

The study compared nearly 996 people with autism to 1,287 control subjects and analyzed their genetic makeup to look for these CNVs.

"It's the largest study of this type thus far to get published," Cantor said.

While the researchers said these genetic variants don't cause autism, they do play a role in determining the risk for developing it.