Last month, an international autism study group, with the help of UW scientists, found a gene linked to a child’s chance of having autism.

The Autism Genome Project was launched about six years ago as a collaborative effort of more than 120 scientists from 50 institutions and universities — including the UW — across 19 European and North American countries.

The group studies genes that may be tied to a child’s susceptibility to autism.

“The goal is to find the genes that are responsible for autism,” said Gerard Schellenberg, a UW geneticist and a molecular researcher for the study.

However, autistic disorders are not caused by just one gene. Scientists believe there may be anywhere from five to 15 major genes that must come together to contribute to autism, as well as an additional 30 - 40 minor genes.

Annette Estes, associate director of the Autism Center Research Program and Psychiatry, recognizes that a variety of knowledge is necessary for research of this magnitude. Psychologists and geneticists must work together, Estes said.

“A project as large as this takes a team of people with very different disciplinary backgrounds,” she said.

While the UW has been studying 350 families, more than half of which are within the Seattle area, the international collaboration has involved 1,400 families. Each has two or more children with an autistic disorder.

“To do genetics you need family material,” Schellenberg said.

This cooperation provides much more data and statistics to work with, Estes said.

There are three main symptoms of autism: difficulty with social interaction, difficulty with communication and repetitive behaviors such as hand waving.

“Autism is a spectrum disorder,” Estes said. “People range in how severely affected they are.”

The group is trying to understand how genes relate to these symptoms, Estes said.

One approach that proves to scientists that autism is genetic is the specific studies of twins, Estes said. In identical twins, who have all genes in common, there is a 90 percent chance of both having autism if one is diagnosed. In fraternal twins, who have the same gene congruency as regular siblings, this percentage drops drastically.

“This tells us that genes play a large role in autism,” Estes said.

The researchers have identified a chromosome, namely chromosome 11, which most likely contains a gene related to autism.

They have also discovered neurexin 1, a gene that Schellenberg said the team is extremely excited about because it handles glutamate, a neurotransmitter that has been implicated in autism.

Finding genes that may lead to susceptibility of autism is important to catch the disease earlier than currently possible, Estes said.

As of now, diagnosis of an autistic disorder usually cannot be made until the child is, on average, between the ages of 3 and 6.

The earlier the intervention, the more the child’s brain development can be improved.

“If we find the genes that lead to autism, we could start working with babies within six to 12 months and try and help keep their brain development on track,” Estes said.

In addition to early intervention, finding what genes are involved with an autistic disorder and what those genes do may give scientists the ability to create drugs that counteract the effect of these defective genes.

This would be especially affective for children who do not always respond to early intervention treatment; these drugs could assist in their progress, Estes said.

Autism occurs in about one out of 1,000 births, while one out of 200 are born with a lesser form of autism.

The UW sector of the Autism Genome Project works with families who signed on voluntarily.

Estes described the families involved in the study as “so incredibly smart and well-informed” about their children’s disorder.

Estes said she finds the participants “inspirational,” noting their dedication is apparent in taking time off from work, filling out questionnaires and having blood drawn.

“They are doing it because they want to find the genes for autism,” she said.

Reach contributing writer Jessica Bray at news@thedaily.washington.edu.