U.S. researchers say they've identified the molecular network underpinning many of the genes that have been shown to be involved in autism spectrum disorders.
The discovery could lead to uncovering more genes specifically linked to autism, as more and more studies strengthen the idea of genetic mutations being at least a contributing factor to the disorders, researchers at Stanford University say.
Their study also suggests a defect in the communication between the two halves of the brain could be behind some cases of autism.
There have been a large number of mutations seen in an extensive number of autism-related genes, which makes investigation of the disorder difficult, says lead study author Professor Michael Snyder of the Stanford Center for Genomics and Personalized Medicine at the Stanford School of Medicine.
"We, therefore, wanted to see to what extent shared molecular pathways are perturbed by the diverse set of mutations linked to autism in the hope of distilling tractable information that would benefit future studies," he explains.
Snyder and his colleagues used a published database of interactions between genes and proteins to create an "interactome," showing all molecular interactions within a cell.
They say they've identified a molecular network within the interactome made up of 119 proteins that shows a "very strong enrichment for autism genes."
Subsequent research on gene expression and genome sequencing of 25 autism patients confirmed a link between the protein interactions and autism-related genes, the researchers report.
The study findings suggest a possible explanation for why the region of the brain known as the corpus callosum, the brain's communication center, is often abnormally reduced in size in people with autism spectrum disorders, the Stanford team says.
Disruption in areas of the corpus callosum may be interfering with the signaling between the brain's two halves, they suggest, causing the characteristics of autism.
The research focused on brain cells known as oligodendrocytes, which produce a substance called myelin, which helps electrical signals move quickly among the brain's neurons.
If genetic mutations cause problems with oligodendrocytes, it could contribute to poor neuronal signaling, they say.
"This is our first glimpse of autism's underlying biological framework, and it implicated a cell type and region of the brain that have not been extensively studied in the disease," Snyder says.
Identifying new autism-related genes represents an advance in research on the disorder, but won't necessarily create new therapies immediately, says study co-author Joachim Hallmayer.
"Many genes have been identified, but environment also plays a role," he says. "This study suggesst a possible way to subdivide patients into smaller, more homogenous populations based on which genes are mutated."