MUC5B and idiopathic pulmonary fibrosis: In fact, a Genome-wide association study (GWAS) found that 38% of subjects with IPF had a minor (T) allele of the single-nucleotide polymorphism (SNP) rs35705950. Moreover, this polymorphism was also associated with 34% subjects with familial interstitial pneumonia and it is linked to 37.4-fold MUC5B upregulation in the lung in unaffected subjects and 5.7-fold MUC5B upregulation in patients with IPF [20,89].