Common Gene Variants Increase Autism Risk

Common gene variants are linked to autism risk, a new study shows.

According to researchers, most of the genetic risk for autism is associated with versions of genes commonly found in the population and not from rare variants.

Spontaneous glitches in DNA accounted for just 2.6 percent of the total genetic risk, while common gene variants accounted for 52 percent of genetic risk.

Autism Spectrum Disorder or ASD is a range of neurodevelopmental disorders characterized by problems in communication, inability to form social connections and restricted, repetitive patterns of behavior. The National Institute of Neurological Disorder and Stroke stated that autism is caused by a combination of both genetic and environmental factors.

The current study was funded by the National Institutes of Health. Scientists at Population-Based Autism Genetics and Environment Study (PAGES) Consortium also worked on the research and it is published in the journal Nature Genetics

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

The study was based on data from Sweden's universal health registry, which allowed researchers to obtain information from 3,000 people with autism and compare the data with age-matched controls. Also, the team used statistical methods that helped them find heritability factors.

The research will lead to a better understanding of molecular mechanisms that drive autism, researchers said.

"Within a given family, the mutations could be a critical determinant that leads to the manifestation of ASD in a particular family member," said Buxbaum. "The family may have common variation that puts it at risk, but if there is also a de novo [spontaneous} mutation on top of that, it could push an individual over the edge. So for many families, the interplay between common and spontaneous genetic factors could be the underlying genetic architecture of the disorder."