Gene variant may help against emphysema, asthma

People who carry a variant form of a gene that encodes a protein called MMP-12 are in luck. This uncommon form of the gene appears to provide some protection against emphysema and asthma, researchers report online December 16 in the New England Journal of Medicine.

In the study, an international team of researchers analyzed data on lung function and genetics from seven studies that included more than 5,000 people and found that 7 to 13 percent of people harbored the beneficial variant of MMP-12.

In four of the studies, the scientists found that tobacco smokers carrying the helpful form of the protein were one-third less likely to develop chronic obstructive pulmonary disease than other smokers. COPD includes emphysema and chronic obstructive bronchitis and is the fourth leading cause of death in the United States after heart disease, cancer and stroke.