MUC5B and idiopathic pulmonary fibrosis: Particularly, sequence variants in genes for the surfactant proteins causing surfactant dysfunction (SFTPC, SFTPA1, SFTPA2, ABCA3), or polymorphisms in MUC5B, causing overexpression of the mucin 5B, or in TOLLIP (an inhibitor of the Toll-like receptors 2 and 4) together to mitochondrial dysfunction are other genetic mechanisms associated with an increased risk of IPF [16].