DURHAM, N.C., Sept. 27 (UPI) -- A deadly incurable lung disorder is caused by a genetic defect plus inhaled chemicals from cigarettes, researchers say.
Idiopathic interstitial pneumonia "is a terrible disease whose causes have remained unclear and for which no treatment exists," said Duke University researcher Mark Steele. "Our findings provide convincing support for a genetic basis. But it's more than that -- development of the disease takes a second hit. One such hit is cigarette smoking."
Idiopathic interstitial pneumonia, or IIP, is a form of pulmonary fibrosis, a group of diseases that scar the lungs and kill victims within five years. The National Institutes of Health estimates up to 15,000 new IIP cases develop each year in the United States.
In a study of 111 families with multiple people with IIP, researchers said they found evidence that a single abnormal copy of an as-yet-unidentified gene can spark the disease.
The findings, reported in the American Journal of Respiratory and Critical Care Medicine, may lead to discovery of the gene responsible and underscore the need for people with a family history of IIP to stop smoking, Steele said.
