The quest to understand autism spectrum disorder seems an unending one. Now, researchers discover 102 genes associated with the disorder. The find virtually doubles the number of genes implicated in the complicated condition.

Curbed Communication

Autism spectrum disorder (ASD) is a developmental condition that affects at least 1 in 59 U.S. children. The disorder usually shows up as a range of symptoms in early childhood when kids are about 2 to 3 years old as a range of symptoms. Individuals with autism have trouble interacting with peers, engage in repetitive behaviors and have difficulty communicating with others. Many are highly sensitive to sounds and other sensations. The disorder is complex and affects individuals differently.

No one knows what causes autism but scientists suspect genetics play a role. Many families show inheritance of autism or related medical conditions such as sleep disturbances, seizures and gastrointestinal disorders that often accompany an autism diagnosis. Previous research identified 65 genes associated with autism, but these studies focused only on new mutations to find genes underlying the disorder.

Serious Search

Jack Kosmicki, a bioinformaticist and Ph.D. student at Harvard University who led the new research, thought that approach was lacking. It ignored other potential sources of genetic variation that could be at play. So, he and his colleagues cast a much wider net. The team analyzed the genetics of more than 37,000 individuals. They assessed new mutations but also genetic differences between affected individuals and case controls.

The researchers identified more than 100 autism-associated genes. When the team compared their results to published studies of individuals with autism, intellectual disabilities and developmental delays, he found about half the genes associated more with autism spectrum disorder than the other conditions that often show up with an autism diagnosis.

“Being able to look at other disorders in connection to ASD is significant and valuable for being able to explain the genetics behind the variety of possible outcomes within ASD,” Kosmicki, who presented the findings today at the American Society of Human Genetics 2018 Annual Meeting in San Diego, California, said in a statement. The discovery could also help untangle the differences between autism and intellectual disability and developmental delay.

For Kosmicki and colleagues, the discovery is a beginning. “We hope to create a resource for definitive future analysis of genes associated with ASD,” Mark Daly, a geneticist at the Broad Institute and Massachusetts General Hospital and one of Kosmicki’s advisors, said in a statement. The researchers hope to combine their results with other large studies of the genetic variation behind intellectual disability, developmental delay and psychiatric traits.