Boy_with_AutismMany recent studies weigh in on the risk factors of autism spectrum disorders (ASD). Some explore the influence of genetic versus environmental factors, while others investigate the effects of specific contributing elements. In a new study, scientists from the Population-Based Autism and Genetics Environment Study (PAGES) Consortium focus on the impact of genetics as a risk factor for autism. They find that common genetic variations account for roughly half the risk for autism. The results may help researchers determine exactly how much genetics affects autism risk.

The researchers based their work on a sample of 3,000 people with autism and a demographically-matched control group. Data for the study is from Sweden’s universal health registry. The research team used new statistical methods to create a best-fit model capable of analyzing the combined effects of multiple genes and environmental factors instead of focusing on individual genetic risk factors.

Around 52% of autism risk is linked to common and rare inherited variation. Spontaneous mutations accounted for only 2.6% of total risk, which means that common genetic factors are the most influential in genetic risk for autism.

“Genetic variation likely accounts for roughly 60 percent of the liability for autism, with common variants comprising the bulk of its genetic architecture. Although each exerts just a tiny effect individually, these common variations in the genetic code add up to substantial impact, taken together,” explained Joseph Buxbaum, Ph.D., of the Icahn School of Medicine at Mount Sinai (ISMMS), New York City.

This research gives scientists the tools to detect both common and rare genetic variations associated with autism. Understanding the genetic risk factors may help scientists identify the specific causes of ASD and find themes in common genetic variations.

This research is published in the journal Nature Genetics.

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