Previous studies had demonstrated that a common variant (rs35705950) in the promoter region of the mucin 5b (MUC5B) gene was significantly associated with susceptibility to familial and sporadic IPF, suggesting a potential role for the distal airways and mucus overproduction in the pathogenesis of pulmonary fibrosis [6,14]. Here, MUC5B is linked to idiopathic interstitial pneumonia.