PARN and pulmonary fibrosis: Most pulmonary fibrosis patients who have a background of familial clustering of familial interstitial pneumonia show mutations in genes that encode surfactant-associated protein C (SFTPC) [178,179], surfactant-associated protein A2 (SFTPA2) [180], telomerase components (TERT and TERC) [181,182], and genes associated with telomere biology, such as poly (a)-specific ribonuclease deadenylation nuclease (PARN) and regulator of telomere elongation helicase 1 (RTEL1) [183].