These findings were presented at the American Thoracic Society International Conference and published online in the New England Journal of Medicine on May 22 and will appear in the July 4, 2013 print edition.
“While this variant of the MUC5B gene is fairly common, pulmonary fibrosis is not. Our findings suggest that pulmonary fibrosis may be a part of a much more common, but likely less severe, syndrome and could potentially be predicted on the basis of the MUC5B genetic variant,” said Gary M. Hunninghake, MD, MPH, a physician researcher in the pulmonary and critical care division at BWH and co-corresponding author of the research paper. “While too early to tell how important this variant may be in clinical practice, this finding could open new research avenues into this disease.”
Researchers looked at a common variant of the gene for mucin-5B, a protein that is a component of the mucous produced by the bronchial tubes associated with associated with pulmonary fibrosis. Their goal was to determine whether this common gene variant was also associated with interstitial lung disease in the general population. To do this, researchers reviewed CT scans of more than 2,600 adults who did not have a clinical diagnosis of pulmonary fibrosis. Researchers found imaging evidence of interstitial lung abnormalities (lung inflammation and scarring) in about 9 percent of those over age 50. In this age group, these abnormal findings were significantly more common among the 19 percent of people with the MUC5B genetic variant. While these abnormalities do not necessarily indicate a disease that will progress, the presence of these abnormalities was associated with more shortness of breath and cough as well as smaller lung sizes and ability to transfer oxygen.
“Our findings provide important insights into the pulmonary effects of a common genetic variant in the general population, and they also suggest that the clinical condition pulmonary fibrosis may be part of the broader spectrum of abnormalities that includes more subtle and asymptomatic findings,” said George O’Connor, MD, professor of medicine at Boston University School of Medicine, director of lung research at the Framingham Heart Study, and a senior collaborator in this study.
Future research efforts will focus on identifying which people with imaging abnormalities are at greatest risk for progression to pulmonary fibrosis, and reciprocally, why some people “at-risk” for pulmonary fibrosis do not develop a clinical disease. The authors believe that this work may eventually pave the way for efforts aimed at preventing pulmonary fibrosis.
In addition to Hunninghake, other researchers from BWH included Hiroto Hatabu, MD, Yuka Okajima, Mizuki Nishino, MD, Tetsuro Araki, Oscar Zazueta, Sila Kurugol, James Ross, Raúl Estépar, Ivan Rosas, MD, and George Washko, MD. In total, twenty-one authors shared credit for the paper, including researchers at Boston University School of Medicine, Vanderbilt University, and the University of Colorado.
This research was supported by the National Institutes of Health (K08 HL092222, 5R21CA11627, K25 HL104085, R01 HL116473, K23 HL089353, R01 HL116473 and R01 HL107246), the National Heart, Lung and Blood Institute (R01-HL095393, R01-HL097163, P01-HL092870, and RC2-HL101715) and the U.S. Veterans Administration.