RTEL1 and idiopathic pulmonary fibrosis: Sequence variants in genes for surfactant proteins (SFTPC, SFTPA1, SFTPA2, ABCA3), polymorphisms in MUC5B or TOLLIP, and mutations in telomere genes (TERT, TERC, PARN, and RTEL1) are associated with an increased risk of idiopathic pulmonary fibrosis (IPF) [17, 18].