Washington: Rare mutations in more than 100 genes affect networks in the brain that result in autism, showed two major genetic studies on the syndrome led by scientists at the University of California.
Sixty of these genes met a 'high-confidence' threshold indicating that there is a greater than 90 percent chance that mutations in those genes contribute to autism risk.
The majority of the mutations identified in the new studies are de novo (Latin for afresh) mutations, meaning they are not present in unaffected parents' genomes but arise spontaneously in a single sperm or egg cell just prior to the conception of a child.
"Before these studies, only 11 autism genes had been identified with high confidence, and we have now more than quadrupled that number," said Stephan Sanders, assistant professor of psychiatry at the University of California, San Francisco (UCSF) in the US.
Based on recent trends, gene discovery will continue at a quickening pace, with as many as 1,000 genes ultimately associated with autism risk, Sanders estimated.
"There has been a lot of concern that 1,000 genes means 1,000 different treatments, but I think the news is much brighter than that," said Matthew State, professor in psychiatry at UCSF.
"There is already strong evidence that these mutations converge on a much smaller number of key biological functions. We now need to focus on these points of convergence to begin to develop novel treatments," State added.
The large research teams behind each of the two new studies used a form of next-generation sequencing (NGS) known as 'whole-exome' sequencing, a letter-by-letter analysis of just the portion of the genome that encodes proteins.
"That we now have a bounty of dozens of genes, and a clear path forward to find perhaps hundreds more, provides an incredible foundation for understanding the biology of autism and finding new treatments," State concluded.
The studies appeared online in the journal Nature.