The study is one of the few to show a strong link between anatomy and autism and may indicate a genetic cause for the syndrome, says Barbara Stewart, MD. She presented the study today at CHEST 2011, the Annual Meeting of the American College of Chest Physicians.
"I think it takes some of the pressure off parents," Stewart tells WebMD. "Autism is not something they did. It just happened."
Stewart, a lung doctor at Nemours Children's clinic in Pensacola, Fla., made the discovery while examining patients referred to her for persistent coughs.
Searching for the cause of their coughs, she examined the passages that take air to the lungs by placing a tiny camera down their windpipes, a procedure known as bronchoscopy. In looking at the lungs in this way, she noticed that several patients had divisions in some of their airways, creating double passages, which she calls "doublets."
Then she noticed that these patients all had something else in common: "Every single one has autism, or autism spectrum disorder," she says.
Stewart says it's possible that the doublets cause more resistance to the air passing into the lungs; these patients tend to be short of breath. But she doesn't think that these patients' breathing problems could be enough to cause any brain damage that might lead to autism.
"I think the whole thing occurs embryologically -- when the cell and egg come together and the fetus is formed," she says. "It's important for parents to know that."
While the information points in new directions for research, there is nothing that parents can or should do with the information, Stewart says. She does not recommend that parents of autistic children have bronchoscopies to see if the doublets are present.
Anatomy and Autism
Altogether, Stewart evaluated 49 children with autism or ASD. That is a small number on which to make any conclusions, Joseph Horrigan, MD, tells WebMD. Horrigan is assistant vice president for medical research at Autism Speaks, a foundation that researchers the disorder.
"The study needs to be replicated," he says, and that will be challenging because bronchoscopy can be uncomfortable for patients.
But if the findings are confirmed by other studies, the research could prove valuable, he says.
So far no one else has found any physical feature that all autistic children share, although there have been recent studies showing that many autistic children have similar facial features, he says.
Other studies have found that many autistic patients have larger brains at age 2, and that babies born at low birth weight are also more likely to have the disorder.
"There is general agreement that both genetic and environmental factors are involved," says Horrigan. "This could lend some understanding to the timing of when development is affected."
These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.