In what’s being called the largest study of its kind, researchers say they’ve identified more than 100 genes associated with autism.

The study, which looked at 35,000 people including nearly 12,000 on the spectrum, pinpointed 102 genes related to autism. Of them, 49 were also associated with other types of developmental delay.

By contrast, just 65 autism-linked genes were known in 2015, according to those behind the new study published online this week in the journal Cell.

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“This is a landmark study, both for its size and for the large international collaborative effort it required. With these identified genes we can begin to understand what brain changes underlie ASD and begin to consider novel treatment approaches,” said Joseph D. Buxbaum, director of the Seaver Autism Center for Research and Treatment at Mount Sinai and a senior author of the study.

Researchers said they were able to analyze inherited genes and those that occur spontaneously when the egg or sperm are formed. They found that genes associated with autism affect the function or development of the brain, both of which can lead to autism.

In addition, the genetic sequencing done for the study showed that autism can affect multiple classes of nerve cells.

“We now have specific, powerful tools that help us understand those underpinnings, and new drugs will be developed based on our newfound understanding of the molecular bases of autism,” Buxbaum said.

A study published last year looking at more than 2 million people around the world estimated that almost 81 percent of autism risk is hereditary.