In fact, mutations in the gene coding for surfactant protein C (SFTPC) and in the MUC5B promoter region are linked to pulmonary fibrosis, but the effects of these mutations are usually not observed until late in life (around 60–70 years old), because age-related decline in proteostasis is needed for aggregation prone or misfolded proteins to actually cause damage (Schneider et al., 2021). This evidence concerns the gene MUC5B and pulmonary fibrosis.