For example, the minor allele frequency of the MUC5B promoter single-nucleotide polymorphism (SNP), widely associated with IPF,15 is found with increasing frequency in patients with chronic HP.16 Short telomeres have also been associated with RA-ILD17 and chronic HP, resulting in a prognosis similar to patients with IPF.16 Patients with RA-ILD and usual interstitial pneumonia pattern have radiological changes that are indistinguishable from IPF and the presence of traction change and honeycombing is associated with poor outcomes regardless of aetiology. Here, MUC5B is linked to idiopathic pulmonary fibrosis.