Researchers claim that nearly 60% of autism risk is genetic, with the implicated variant genes being common among the general population. They publish the results of their research in the journal Nature Genetics.
By conducting a "rigorous analysis" of DNA sequence variations as part of the Population-Based Autism Genetics and Environment Study (PAGES) Consortium, Dr. Buxbaum's team found that about 52.4% of autism cases can be traced back to both common and rare inherited variations. By contrast, spontaneous mutations were found to account for just 2.6% of total autism risk.
"We show very clearly that inherited common variants comprise the bulk of the risk that sets up susceptibility to autism," Dr. Buxbaum says. "But while families can be genetically loaded for autism risk, it may take additional rare genetic factors to actually produce the disorder in a particular family member."
The study used data from Sweden's universal health registry to compare about 3,000 participants, including autistic subjects and a control group. The researchers say that PAGES is the largest study of its kind to date.