Thursday, June 10, 2010

Research unravels autism genes

Vanderbilt doctors on team that uncovers crucial clues

By Christina E. Sanchez • THE TENNESSEAN • June 10, 2010

Researchers have identified more than 100 genes that may be responsible for autism, and they say the findings could lead to new treatments for the disorder.

A new autism study — the largest of its kind — released Wednesday revealed that people who have autism spectrum disorder either lack or have extra copies of multiple genes vital in the development and function of the brain.

More than 120 researchers, including two at Vanderbilt University, finished the five-year international study and published it in the journal Nature. The results could lead to new ways of studying and looking at autism, a neurodevelopmental disorder that inhibits a person's ability to communicate and interact socially. It affects 1 in 110 children. The cause and cure of autism are not known.

Researchers said the discoveries were significant, but they also learned that autism is even more complex than they understood and more genes are involved than previously thought. Also, the affected genes are not the same in all people with the disorder.

"We now have starting points. We have some clues, and five years ago we had no clues," said Dr. Jonathan Haines, director of the Center for Human Genetics Research at Vanderbilt and co-author of the study. "We have a lot more work to do, but we are making progress. It is starting to make sense."

The other Vanderbilt researcher was Dr. James Sutcliffe, associate professor of molecular physiology and biophysics and of psychiatry. Sutcliffe and Haines collected samples from participants, helped design the study and analyzed data.

In the study, researchers compared the DNA of 1,000 people with autism spectrum disorder with that of 1,300 people without it for the Autism Genome Project, an international research initiative.

Researchers and advocates hope the results will mean better treatments and diagnosis of the disorder. Right now, doctors can treat autism with behavioral and educational interventions, but they have no proven medical therapies. Also, diagnosis can be difficult since no blood test exists. In some cases, a child may not be diagnosed until age 5, and that is based on symptoms that can include a lack of communication, poor social interaction and an inability to make eye contact.

Family 'encouraged'

Tammy Vice wishes for more ways she can help her 16-year-old daughter, Morgan, who has moderate autism. The Vice family participates in autism studies when possible to look for answers.

"One of the most baffling things to me — I know how bright my child is because she can get on the computer and blow you away with games, but some of the most common-sense things are beyond her," said Vice, who is active with the Autism Society of Middle Tennessee. "We are encouraged to know they are one step closer to getting the answers needed by so many."

Autism has been a hard disorder for scientists to understand. They had believed there were a few commonly related genes among people with autism. The newly found autism-related genes could explain why different people show different symptoms.

"If we are missing some of these genes, essentially the blueprint of how the brain cells should interact is not quite where it would be," Haines said. "If you get enough differences, you get the behaviors associated with autism."

For Morgan, the hardest behavior can be her obsessive-compulsive disorder, which sometimes mixes with her uncanny ability to remember details from years ago.

"Sometimes she will request a toy she had from 11 or 12 years ago," Vice said. "It's very hard to get rid of things because she will ask for them."

The prevalence of autism over the past two decades has grown from about 1 in 10,000 in 1990 to about 1 in 110. Boys are diagnosed at a rate of about 1 in 80.

Dr. Zachary Warren, director of the Vanderbilt Kennedy Center Treatment and Research Institute for Autism Spectrum Disorders, said the rate probably increased because of better diagnosis and greater awareness. "It's not that people with autism spectrum disorder didn't exist before, but they may not have been diagnosed with it," said Warren, who was not an investigator in the study. "They may have been identified with a different behavioral diagnosis."

Study to expand
Warren said knowing the genes responsible could lead to targeted therapies based on a child's biology.

"Autism can be quite an impairing condition for children and adults," Warren said. "The cost — to kids, to families, to schools — is great, and it is imperative to think about ways to understand autism, its causes and how best to treat it."

The study on the new genes linked to autism will continue and expand, said Haines, who envisions the next phase could involve about 5,000 participants. Researchers also have to figure out how each of the genes discovered works and look to see if each is related to subtypes of autism.

"We will look at the genes in more detail," Haines said. "We are on a roll, and we will make progress more quickly."

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