Chicago ? Researchers have found genetic variations that are significantly more common in people with autism, a discovery that may improve diagnosis and offers the promise of developing treatments for the frustratingly mysterious disorder.

The findings, published in the journal Nature, compared the genomes of thousands of autistic people to those of thousands of people without the disorder — a massive task that new technology only recently made possible. The genome is the complex system of DNA coding that builds and runs the human body.

Autism was linked to a genetic variation in a portion of DNA that affects the way brain cells connect with one another. Scientists also reported a link between autism and small “mistakes” in another DNA segment involved with cell communication.

Both reports add weight to the idea that autism is related to problems with the connections among brain cells.

“It is very exciting,” said study leader Hakon Hakonarson, director of the Center for Applied Genomics at Children’s Hospital of Philadelphia. “It opens up the opportunity someday for new interventions to fix the bad consequences this variant has on brain function and development.”

A disorder marked by impaired communication skills and ability to interact, autism affects one in 150 children in the U.S., according to the Centers for Disease Control and Prevention.