Autism: Airway abnormality

A researcher has found an abnormality in the airways of children with autism that she says may be the first anatomical marker for the neurodevelopmental disorder.

While examining children with autism who came in for a persistent cough, Dr. Barbara Stewart used a bronchoscope -- which can see down into the windpipe and the airways that branch into the lungs -- and noticed something different about those branches.

In a typical lung, the windpipe, or trachea, branches into two main stems. From there, airways branch off the stems much like tree branches in a random, asymmetrical pattern, said Stewart, a pediatric pulmonologist at Nemours Children's Clinic in Pensacola, Fla.

But in the autistic children, those branches were instead doubled up and symmetrical. And the branches were smaller -- whereas in a normal lung you might have one large branch jutting off, in the autistic child, she'd see two, smaller branches instead.

Stewart went back and looked at the bronchoscopy results of 49 children with autism spectrum disorder and more than 300 kids without the condition. She found that all of the kids with autism had what she calls symmetrical "doublets" in their airways, while none of the normally developing kids did.

"I don't know what the significance of that is … But it looks like they have more of everything," Stewart said, adding that all of the autistic children had normal lung function and the anatomical difference may or may not explain the cough.

The research is scheduled to be presented Monday at CHEST 2011, the annual meeting of the American College of Chest Physicians, in Honolulu. Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.

Dr. Daniel Coury, medical director for the Autism Treatment Network of Autism Speaks, said he wasn't sure what to make of the findings, since there aren't reports of children with autism having any particular issues with their lungs.

And yet, he said the findings warrant more research, particularly whether there might be some gene or region of a chromosome that plays a role in both brain and lung development and is associated with autism.

"I've never heard of anything like this before and certainly, your first thought is, 'If autism is a neurodevelopmental disorder, why would we be finding problems in the lungs?'" Coury said. "The fact is we are thinking more and more that autism is a whole-body disorder.

We are seeing some people with autism that have lower gastrointestinal problems and immune problems. So, once you toss aside the idea that this is strictly a brain problem and think of it as a whole-body problem, this becomes possible."

Airway structures begin to develop in utero during the first trimester and continue until about 20 weeks, Stewart noted. The difference in lung structure among children with autism spectrum disorder was difficult to spot at first, she added.