New Genetic Clues to Autism Found
2 New Gene Mutations Linked to Autism
Tracking the Autism Genes continued...
Next, Notterman's team validated the finding to see if the genes were expressed in the brain. They found that NCAM2 was ''expressed in some regions of the brain that may be associated with autism -- the hippocampus and the cerebellum."
''Many of the genes described [recently as having a link to autism] are genes involved in the synapse," Notterman says. A synapse is a specialized junction at which a nerve cell communicates with another cell.
The genetic mutation of NCAM2 is probably rare, Notterman says. "We would estimate that 0.5% or fewer of kids with autism have the NCAM2 [mutation]."
"About six to 10 rare genetic mutations to date have been associated with autism," Notterman says. "Most people working in the field predict there will be 50 to 100."
Some parents and siblings of the children with autism were found to have the NCAM2 mutation but not the disorder, which the researchers expected to find. This suggests other genetic factors or environmental triggers play a role.
Notterman conducted the research while at Princeton University. The research was supported by the Simons and Nancy Laurie Marks Foundations and the AGRE Consortium.
Tracking Autism Genes: Implications
While there is no immediate application of the discovery for parents, Notterman says the new research suggests that ''science is probably on the right track over the next decade to understand much more about the basic biology of autism.''
The recurring theme recently, he says, is the finding of structural variations in the DNA that cause mutations in the genes affecting the synapses.
The new findings reflect the complexity of the origin of autism, says Daniel Coury, MD, chief of developmental and behavioral pediatrics at Nationwide Children's Hospital in Columbus, Ohio, and medical director of the Autism Treatment Network, a consortium of 14 U.S. and Canadian sites focused on improving treatment.
''There was the popular belief that we were going to find 'the gene,'" says Coury, who reviewed the study results for WebMD.
''That got expanded," he says, as ongoing research turned up several more genetic mutations associated with autism.