Study Links Autism To Gene Defects

CBS News Medical Correspondent Dr. Jon LaPook Explains

(CBS)  Austin and Nathaniel Lewin, 10 year-old identical twins, have been slow learners. Their parents worried what could be wrong. Could it be autism?

According to Morrie Lewin, the boys' father, he felt very guilty. "You wonder something you did or something in your genes or something you had no control over is somehow been passed on and is affecting your kids," he says.

A new study in the New England Journal of Medicine says a certain genetic glitch increases the risk of autism by 100 fold. This defect appears to account for about 1 percent of autism - an estimated 15,000 cases.

"Ultimately, we think that this could act as a signpost to guide us to what genes might be particularly important in autism," says Dr. David Miller of Children's Hospital in Boston.

When the brothers were tested at Children's Hospital in Boston, doctors found they were each missing a piece of DNA - the same defect identified in the new report. Finding a genetic link to autism is a relief to their parents, because it could help them get the right treatment.

"I think this is going to be a big help for a lot of parents whose kids have been tested for the/big syndromes that are out there," says Robin Lewin, the boys' mother. "Now they're finally going to get an answer like we have."

You can get this test through some labs and large academic hospitals. It costs $2,000 to 3,000 dollars. While this discovery accounts for a fraction of autism, it's another step toward mapping all the genetic causes of this baffling disorder.