Idiopathic pulmonary fibrosis (IPF), the most common type of idiopathic interstitial pneumonia (IIP), is a chronic, irreversible and typically fatal fibrotic lung disease, which is characterized by overproduction and disorganized deposition of extracellular matrix (ECM) proteins, together with abnormal proliferation of mesenchymal cells, ultimately leading to distortion of pulmonary architecture and impairment of pulmonary functions (Okamoto et al., 2011; Wolters et al., 2018). The gene discussed is PROS1; the disease is idiopathic pulmonary fibrosis.