Racking up some $14.5 billion in annual U.S. costs and resulting in more than 5,000 American deaths each year, asthma is becoming an increasingly worrisome epidemic. Recent research has emphasized the condition¿s strong environmental triggers, such as diesel-powered truck emissions or dust mite-infested carpets, but scientists have long known that heredity also plays a significant role in disease onset. Now a new study, published online by the journal Nature, documents the discovery of a gene linked to increased asthma susceptibility.

Tim Keith of Genome Therapeutics and his colleagues conducted genome-wide scans of 460 Caucasian families, each of which had at least two children with doctor-diagnosed asthma. They found that a gene called ADAM33 is strongly associated with both increased occurrence of asthma and inflammation of the airways, one of the main components of asthma. As it turns out, this makes sense because the protein that this gene encodes is expressed in human lung and muscle cells. "The airways in asthma patients undergo a number of changes, such as thickening of the airway walls and subsequent narrowing of the airway passage," team member Stephen Holgate explains. "These changes contribute to the overall airway responsiveness and related breathing problems in asthma. Our studies suggest ADAM33 plays a role in this remodeling and may underlie abnormalities in asthmatic airway function."

Knowing that a person possesses a disease-linked variant of this particular gene could one day enable doctors to begin early preventative treatment. "This research has provided not only a novel target for drug discovery, but also insights into the pathways and pathogenic mechanisms underlying asthma," remarks Cecil B. Pickett, president of the Schering-Plough Research Institute in Kenilworth, N. J., home to many of the study¿s researchers. Right now, doctors must treat asthma after it has already begun to suck the breath out of its victims. Perhaps in the future, we can stop the disease before it even starts.