Researchers discover many genetic keys needed to unlock autism

Hundreds of small genetic variations are associated with autism spectrum disorders, including an area of DNA that may be a key to understanding why humans are social animals, according to a multi-site collaborative study led by researchers at Yale University.

Published in the June 9 issue of the journal Neuron, the study reinforces the theory that autism, a disorder that develops in involving impairments in , language deficits and distinctive behaviors, is not caused by one or two major , but by many small variations, each associated with a small percentage of cases.

The study—led by Matthew State, M.D., Ph.D., the Donald J. Cohen Associate Professor of Child Psychiatry, Psychiatry and Genetics—looked at more than 1,000 families in which there was a single child with an autism spectrum disorder, an unaffected sibling and unaffected parents. The team, including postdoctoral fellow and first author Stephan Sanders from Yale, compared individuals with autism to their siblings to determine what types of genetic changes distinguished the affected child from the unaffected child.

"Thanks to an ambitious collaboration among a large group of autism researchers from around the country, supported by the Simons Foundation, we were able to focus on an ideal study population," said State, who is co-director of the Yale Program on Neurogenetics. "It made all the difference in our ability to identify several regions of the genome clearly contributing to autism."

One of the most intriguing of these findings points to the same small section of the genome that causes Williams syndrome—a developmental disorder marked by high sociability and an unusual aptitude for music.

In autism, there is an increase in the chromosomal material, an extra copy of this region, and in Williams syndrome, there's a loss of that same material," said State. "What makes this observation particularly interesting is that Williams syndrome is known for a personality type that is highly empathetic, social, and sensitive to the emotional state of others. Individuals with autism often have difficulties in the opposite direction. This suggests that there is an important key in that region to understanding the nature of the social brain."

State and his team also found about 30 other regions in the genome that are very likely contributing to autism and are focused on about six of those regions that showed the strongest evidence. "We're now moving on to a second phase of the study looking at an additional 1,600 families and should be able to identify multiple new regions that are strongly implicated in autism," he said.

Sanders and State are optimistic about the new findings, pointing out that genetics is the first step to understanding what's really going on at the molecular and cellular level of the brain. "We can use these genetic findings to begin unraveling the underlying biology of autism," said Sanders. "This will help tremendously in the effort to identify new and better approaches to treatment."

Two other studies published in the June 9 issue of Neuron report on the same families studied by State, Sanders and their co-authors. One of these, by a group at Cold Spring Harbor Laboratory in New York, paints a very similar picture—that autism is a highly genetically diverse disorder and that sporadic changes in the structure of the genome present only in the affected individuals and not in other families often play a key role. The other study, by researchers at Columbia University, suggests that although hundreds of genes may be involved in , they appear to disrupt a common molecular network involved in the mobility of brain cells and development of synapses between them.

More information: Christopher Mason, Rahul Dhodapkar, Vikram Fielding-Singh, Daniel Fishman, Sindhuja Kammela, Brian O'Roak, Rebecca Pottenger and Ilana Yurkiewicz. Neuron, Vol. 70, Issue 5 (June 9, 2011).

Related Stories

Brain scans detect autism's signature

Nov 15, 2010

An autism study by Yale School of Medicine researchers using functional magnetic resonance imaging (fMRI) has identified a pattern of brain activity that may characterize the genetic vulnerability to developing autism spectrum ...

Tiny, spontaneous gene mutations may boost autism risk

Mar 15, 2007

Tiny gene mutations, each individually rare, pose more risk for autism than had been previously thought, suggests a study funded in part by the National Institute of Mental Health, a component of the National Institutes of ...

Study adds to evidence that autism has genetic basis

May 02, 2010

Although there is no known cause of autism, studies have shown that mutations in several genes are associated with the developmental brain disorder. New research has uncovered two additional genes that may be involved with ...

Recommended for you

Stress reaction may be in your dad's DNA, study finds

Nov 21, 2014

Stress in this generation could mean resilience in the next, a new study suggests. Male mice subjected to unpredictable stressors produced offspring that showed more flexible coping strategies when under ...

More genetic clues found in a severe food allergy

Nov 21, 2014

Scientists have identified four new genes associated with the severe food allergy eosinophilic esophagitis (EoE). Because the genes appear to have roles in other allergic diseases and in inflammation, the ...

Brain-dwelling worm in UK man's head sequenced

Nov 20, 2014

For the first time, the genome of a rarely seen tapeworm has been sequenced. The genetic information of this invasive parasite, which lived for four years in a UK resident's brain, offers new opportunities ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.