The presence of extra bronchial passageways in children may be a marker for autism and autism spectrum disorders, results from a novel study demonstrated.

"Autism continues to remain underdiagnosed or missed altogether, unrecognized and undiagnosed because appropriate tools for screening for autism have not been available," lead investigator Dr. Barbara A. Stewart said during an interview in advance of the annual meeting of the American College of Chest Physicians, where the study was presented. "Until now, there has been no objective evidence for autism spectrum disorder."

Dr. Stewart of Nemours Children’s Clinic in Pensacola, Fla., conducted bronchoscopic evaluations in 49 children younger than age 18 years who had autism or autism spectrum disorder and were seen in a pulmonary clinic with a diagnosis of cough that was unresponsive to therapy. She noticed that although the airways of the children initially appeared normal, the lower airway had doubled branches, or "doublets" as she calls them.

"Another way to think of this is systematic doubling of airways in the lower airways," Dr. Stewart explained. "When airways divide beyond the first generation, they typically branch like a tree, with one branch on one side and one on the other. A doublet occurs when there are twin branches that come off together instead of one, which are exactly symmetrical, in each of the lower locations that can be seen."

Because of a lack of uniformity in nomenclature in the medical literature, Dr. Stewart said that it’s difficult to determine if doublets have been previously identified, let alone studied. "There are no known studies in the literature attempting to define or even speculate on a function, purpose, role, [or] significance of the ‘double take-off’ airway anomaly," she said.

She speculated that children with doublets may have higher airway resistance, which "might be why the population of children with autism spectrum disorder are not truly athletic people."

Although the potential association between autism and airway structure is intriguing, Dr. Stewart emphasized the preliminary nature of the findings. "That there is such a compelling correlation between a perplexing bronchial anomaly and a seemingly unrelated condition such as autism begs further study," she said. "This discovery needs to be validated by much larger–scale investigations than my own."

She went on to note that research into neurodevelopmental processes, including autism and autism spectrum disorder, and anatomical anomalies such as doublets in the bronchi "should and will be accelerated." She also expressed the hope that "likely less-invasive alternatives to bronchoscopy will be discovered in the near future to justify identification of airway anomalies as a diagnostic tool for autism."

Dr. Stewart said that she had no relevant financial conflicts to disclose.