Chapel Hill, N.C. — One out of every 150 children – mostly boys – will be diagnosed with an autism spectrum disorder (ASD). Not much is known about who is at risk. However, University of North Carolina researchers have just received a large grant to help find answers.

Autism Speaks is the world's largest autism science and advocacy organization. It has committed $5 million to investigate genetic and environmental risk factors for autism. The money will go to studies at UNC and Drexel University in Philadelphia.

Parents of children with autism, like Maggie Dennison, hope the research will help uncover the genetic markers of the disorder.

Dennison said she first noticed some odd behaviors at the end of her son's first year.

“I noticed that he flapped his hands,” Dennison said.

By age 5, Matthew was diagnosed with Asperger's Syndrome, a condition on the milder side of autism spectrum disorders.

Dennison was even more concerned for 15-month-old Jacob, who, being the younger brother of a child with autism, was at greater risk of the disorder himself.

The Dennisons are part of UNC studies in which researchers will follow 500 siblings of autistic children at ages 6, 12 and 24 months.

Using neuro-imaging and personal evaluation, research has identified the earliest physical and behavioral signs of autism. With federal funding and money now from Autism Speaks, the researchers will look into the genetic roots of the disorder.

The study aims “to give us insights into what's going on genetically that underlies this brain overgrowth and this onset of autistic symptoms,” said Dr. Joe Piven, with the UNC Autism Center.

The goal is also to help pinpoint early diagnosis of children with autism.

“That's a potential time, if we can identify those kids at highest risk, when we can have aggressive early intervention,” Piven said.

So far, 15-month-old Jacob shows no signs of the disorder, but his mother hopes the research will help other families and prevent more children from developing autism.

"I really would like to have it stop with this generation," Dennison said.

The Drexel University study will focus on identifying environmental risks factors for autism.

The two studies will operate in multiple sites throughout the United States and will include more than 2,000 infant siblings of children with autism.