New Genetic Clues to Autism Found
May 3, 2010 — Researchers have discovered two new genes that may be involved with autism, the brain disorder marked by difficulty in communicating and relating to others.
The evidence for one of the two new “susceptibility genes” is stronger than that for the other, says Daniel Notterman, MD, the senior author of the study and a professor of pediatrics, biochemistry, and molecular biology at Penn State College of Medicine in Hershey.
One of the newly discovered gene mutations is in NCAM2 and the other is in PTPRD.
“We are more confident about NCAM2 and less about PTPRD,” Notterman tells WebMD.
The researchers announced the discovery Sunday at the Pediatric Academic Societies annual meeting in Vancouver, British Columbia.
Autism or autism spectrum disorder, involving less severe forms of the condition, affect one in 110 U.S. children, according to estimates from the CDC.
The new finding, Notterman says, adds to the growing evidence for genetic links for autism but doesn’t rule out a role for environmental factors. “Over the last couple of years, beginning in 2007, it’s become clear that some cases of autism, maybe up to 15%, will be caused by rare mutations, either occurring spontaneously or that can be inherited by a parent,” he says.
Tracking the Autism Genes
Notterman and his colleagues analyzed data from the Autism Genetic Resource Exchange (AGRE), a collaborative gene bank for autism, on 943 families, most of whom had more than one child diagnosed with autism. In all, they evaluated 3,742 family members.
They compared these with genetic data from 6,317 people without developmental or neuropsychiatric conditions.
Comparing genetic information on those affected with autism and those not, Notterman says, ”gave us a starting list of about 25 genetic mutations” found more commonly in those with autism.
Next, the researchers looked at whether the 25 were substantially different in the two groups, and in the process narrowed the list of suspect genes to four.
Two of the four had already been identified by researchers as linked with autism. The other two were new. “No one had shown this [link] statistically,” Notterman says.