Gene might contribute to asthma risk

Variations in a gene called ADAM33 may predispose a person to asthma.

Scientists discovered ADAM33 on chromosome 20 by comparing blood samples from people with and without asthma. The team also identified dozens of variant forms of the gene that show up more frequently in people with asthma than in healthy people, says study coauthor Tim P. Keith of Genome Therapeutics Corp. in Waltham, Mass. She and her colleagues report the findings in the July 25 Nature.

The wheezing and coughing of asthma result when immune cells instigate inflammation in lung tissue, usually in response to an irritant such as cold air, dust, or smoke.

While the function of the protein encoded by the ADAM33 gene remains unknown, early evidence suggests that altered versions of the protein contribute to biochemical processes that thicken tissues lining the airways.

Keith and her colleagues are trying to discern the normal role of the protein in hopes of