The findings, based on genetic samples from nearly 1,200 families with two or more children who have autism, were published today in Nature Genetics by more than 120 scientists from Europe and
The project was launched in 2002 by scientists at 50 institutions to share data, samples and expertise in an effort to speed up the process of identifying susceptibility genes, those that heighten a child’s risk of having the developmental disorder. Seven
The research was funded by Autism Speaks, a nonprofit organization dedicated to increasing awareness of autism and raising money to fund autism research, and the National Institutes of Health.
The consortium scientists utilized statistical power from the largest set of autism-related genetic material yet examined. The researchers found neurexin 1, part of a family of genes that plays a role with the neurotransmitter glutamate, and a still-to-be-pinpointed gene on chromosome 11 to be likely susceptibility genes for autism.
“Neurexin 1 is a highly likely candidate,” said Schellenberg, a researcher at the
“As for the chromosome 11 location, we think there is another susceptibility gene there and we are actively pursuing it. We are in the neighborhood and have a plan to find it.”
Dawson, who directs the UW’s
The Autism Genome Project used two techniques to examine the DNA of the nearly 1,200 families with a history of autism. Researchers used so-called “gene chip” technologies to look for genetic similarities among these family members. In addition, the team scanned the same DNA for what are called copy number variations. These are submicroscopic insertions and deletions of genetic material that scientists believe may be involved with autism and other common diseases.
Schellenberg said copy number variations are fairly common in the human genome and many of them are believed to be benign. “But until you know the function, you don’t know what happens when there is an insertion or deletion of this genetic material,” he added.
Scientists believe that there may be five or six major genes and perhaps as many as 30 other genes involved in autism. Inheriting more of these genes or certain ones is thought to increase a child’s likelihood of being born with autism or a more severe form of the disorder, just as there are genes that heighten a person’s chances for inheriting breast cancer or heart disease.
Autism is actually a spectrum of disorders that inhibits a person’s ability to communicate and develop social relationships. It is often accompanied by extreme behavior challenges. Autism Spectrum Disorders are diagnosed in one of 166 children in the and affect four times as many boys as girls.
“These findings are a piece of the puzzle. As we identify these genes we will be able to screen young children for autism at an early age and begin interventions earlier, which can have a dramatic effect for some children,”
A second phase of the Autism Genome Project also was announced today to continue the effort to discover the genes that cause the disorder. This $14.5 million phase is being funded by Autism Speaks, the British Medical Research Council, the Health Research Board of Ireland, Genome and its partners, Canadian Institutes for Health Research, Southwest Autism Research and
Other UW researchers who contributed to the research are Annette Estes, Jeff Munson, Elena Korvatska, Ellen Wijsman and Chang-En Yu.