Gene Variants Hold New Clues to Autism
Researchers Identify Gene Mutations That May Raise Risk of Autism Spectrum Disorders
Gene Variant Study continued...
"When we looked to see if any particular regions of the genome looked different, only one region came up," Hakonarson tells WebMD. It was in the region of chromosome 5 involving the genes that facilitate cell-to-cell communication -- CDH9 and CDH10. These genes carry codes to produce crucial neuronal cell-adhesion molecules, Hakonarson says. "They sit on the surface of nerve cells and facilitate and create cell-to-cell communication."
No other common gene variants have been identified and replicated in independent studies with the same scientific rigidity, Hakonarson says.
With the new discovery, the hope is to identify children having these variants at birth or even in utero so intervention can begin early, Hakonarson says. Eventually, he says, the goal would be to create specific treatments to correct the gene variant.
DNA Duplications and Autism Risks
In the second study, Hakonarson and colleagues used the same genome-wide association approach to find genes that were either duplicated or deleted in those with autism or ASD. For this study, the researchers looked at 2,195 children with ASD and 2,519 children without ASD.
They found some previously reported genes, but also some new ones.
And the newly discovered gene variants tended to affect genes involved in cell adhesion, linking the findings to those in the first study.
Search for Genetic Variants
In another study, published online in the Annals of Human Genetics, Margaret Pericak-Vance, PhD, director of the Miami Institute for Human Genomics at the University of Miami Miller School of Medicine, searched for small genetic variants associated with ASD also using a genome-wide association approach.
She used a data set of 438 families with autistic children and then validated the findings with another data set of 487 families with autistic children.
"We found basically the same thing as the Nature paper,'' she says. In addition to multiple and rare gene variants, she concludes that part of "complex genetic architecture of autism involves common variation."
She calls the new research "the most significant finding to date, the most universal finding to date, that clearly shows common gene variants can play a role in giving someone a risk for autism."