Earlier this month, the Autism Genome Project — which includes several Yale researchers — announced that it has finished the first phase of its effort to identify the genes that cause autism.

The project was founded in 2002, and Phase One involved the sequencing of gene samples from more than 1,200 families around the world. Using gene chip technology, the researchers discovered a link between autism and two genetic factors­ — the gene neurexin 1, which is involved in the synthesis of the neurotransmitter glutamate, and a region of chromosome 11 whose function remains unknown.

The project is comprised of 120 scientists and clinicians from 50 institutions and 19 countries, and its first phase was funded by the National Institutes of Health and Autism Speaks, a national nonprofit. The research done at Yale was undertaken by genetics professor Matthew State, Child Study Center Director Fred R. Volkmar and Ami Jm Klin, a professor of child psychiatry.

Klin said the project is a coalition of many smaller research groups.

“We have been doing this together with the British and others for the past 10 years,” he said. “If there is something else to celebrate here it is that the leading research centers around the world, rather than being victims of small-number studies, put their [own goals] aside to make advances in science with an impact around the world.”

Klin said that as more genes for autism are discovered, clinicians will be able to consider treatments such as gene therapy or pharmacological control of the proteins responsible for autism.

According to many scientists involved in the project, however, these discoveries are just a small step toward solving the autism problem.

Jonathan Green, a professor of child and adolescent psychiatry at the University of Manchester who led the clinical fieldwork there, said the project was significant for the size of its sample pool, but that it is just “a step on the road to defining the genetic origins of autism, rather than the end of the road.”

Klin said that two years ago, there was a breakthrough when certain genes associated with autism were found, but this was only the beginning of the search for the exact causes of autism and how the disease can potentially be cured. The specific alleles of neurexin 1 and other genes known to be responsible for the condition have yet to be identified.

“What happens with science is that when you get what you wish for, you realize that the question you were asking is much more complex,” he said. “Therefore, we take those findings with a level of endurance because we know that the road is much longer than we thought.”

Phase Two of the Autism Genome Project is scheduled to begin soon. This second phase represents a $14.5 million, three-year investment by Autism Speaks, the British Medical Research Council, the Health Research Board of Ireland, Genome Canada and its partners, Canadian Institutes for Health Research, Southwest Autism Research and Resource Center, and the Hilibrand Foundation.

Anthony P. Monaco, director of the Wellcome Trust Centre for Human Genetics at the University of Oxford, led the bid for Phase Two.

“We will perform a [much larger] genome-wide scan … where we can hopefully identify exact alleles of genes that might be increasing the risk for autism,” Monaco said.