Research Highlights Genetic Risk for Autism

April 29 -- TUESDAY, April 28 (HealthDay News) -- Inheriting abnormal mutations of two common genes can raise the risk for developing autism, according to one of two new studies highlighting the complex genetic roots of the disorder.

Both genes are located in the brain's frontal lobe region, responsible for complex social behavior and abstract thought, and are normally involved in the proper functioning of healthy brain cell connections. Both also play a key role in the formation of those connections, or synapses, which allow brain cells to communicate and enable learning, cognition, and memory.

The second study found that the risk for autism may rise in rare instances when normal DNA variations disturb genes along a particular neural pathway, one linked to smooth nervous system development and synapse function.

"By using state-of-the-art technology and large samples, we discovered new genes that appear to increase susceptibility to autism," said Geraldine Dawson, a co-author of both studies and the chief science officer of Autism Speaks, an international funder and advocate for biomedical autism research.

"The main point," she said, "is that these genes appear to act in conjunction with other genes -- some of which are identified already, but most of which are not yet identified -- to impact on the way synapses, or brain cell connections, are made."

"And the other point is that the genes that were found are associated with a specific pathway in the brain," Dawson said. "And this is important in that we might eventually be able to begin to develop treatments to target this specific biochemical pathway."

Dawson worked in collaboration with Dr. Hakon Hakonarson, director of the Center for Applied Genomics at the Children's Hospital of Philadelphia and the study's leader; Gerard D. Schellenberg, a professor of pathology and laboratory medicine at the University of Pennsylvania; and Kai Wong, also at Children's Hospital.

Hakonarson, Schellenberg and Wong presented the findings Tuesday during a London-based teleconference. They are published online today in Nature.