Telomerase mutations are associated with short telomeres,8 which lead to increased disease progression,14 whereas MUC5B and Toll interacting protein (TOLLIP) variants are associated with reduced disease progression.10, 15 However, these genetic abnormalities account for only about 30% of the genetic risk associated with IPF, and the molecular mechanisms that become dysregulated remain to be established.13 Here, MUC5B is linked to idiopathic pulmonary fibrosis.