Idiopathic Interstitial Pneumonia arises from combination of a genetic predisposition and inhaled chemicals damage, notably cigarette smoking

... An incurable, deadly lung disorder, "idiopathic interstitial pneumonia" (IIP), whose causes were mysterious arises from a combination of a genetic predisposition and damage due to inhaled chemicals, notably from cigarette smoking, Duke University Medical Center researchers have found. They said their findings could lead to a treatment, but more immediately represent a warning to people with the genetic predisposition not to smoke... click link for more info. ...