Common gene variants account for most of the genetic risk for autism

July 23, 2014

Researchers at the Icahn School of Medicine at Mount Sinai published a new study recently in the online version of Nature Genetics revealing that nearly 60% of the risk of developing autism is genetic and that most of that risk is caused by inherited variant genes that are common in the population and present in individuals without the disorder.

Autism is thought to be caused by an interplay of genetic and other factors, but there has been no consensus on their relative contributions and the nature of its genetic architecture. Recently, evidence has been mounting that genomes of people with autism are prone to harboring de novo mutations—rare, spontaneous mutations that exert strong effects and can largely account for particular cases of the disorder. However, the current study found that 52.4% of autism was traced to common and rare inherited variations, with spontaneous mutations contributing a modest 2.6% of the total risk.

“This is a different kind of analysis than employed in previous studies,” says Thomas Lehner, PhD, Chief of the National Institute of Mental Health’s (NIMH) Genomics Research Branch. “Data from genome-wide association studies was used to identify a genetic model instead of focusing on just pinpointing genetic risk factors. The researchers were able to pick from all cases of illness within a population-based registry.”

Now that the genetic architecture is better understood, the researchers are identifying specific genetic risk factors detected in the sample, such as deletions and duplications in genetic material and spontaneous mutations. Even though such rare spontaneous mutations accounted for only a small fraction of autism risk, the potentially large effects of these glitches make them important clues to understanding the molecular underpinnings of the disorder, say the researchers. Read the article preview.

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