A common single nucleotide polymorphism (SNP) in the putative promoter region of the mucin 5B (MUC5B) gene (rs35705950), which encoded a glycosylated macromolecular component of mucus, has been associated with familiar pulmonary fibrosis and sporadic pulmonary fibrosis [27,28,29,30,31,32,33,34]. This evidence concerns the gene MUC5B and pulmonary fibrosis.