Different molecular abnormalities have been found in IPF as well as in UIP-associated AIDs, e.g., premature aging of pneumocytes due to mutations of telomere maintenance genes [20–22], mutations of surfactant apoprotein genes [23–25], contributing to prolonged inflammation, and promoter mutation in MUC5B [26, 27], which might reduce mucociliary clearance and disrupt regeneration [28]. Here, MUC5B is linked to idiopathic pulmonary fibrosis.