Scholand MB et al. – This study evaluated the impact of MUC5B variant on the expression of cough, a frequent disabling symptom seen in subjects with idiopathic pulmonary fibrosis (IPF). The presence of the minor allele of a MUC5B promoter polymorphism affects the severity of cough in IPF. This implies a possible genetic mechanism for phenotypic heterogeneity in pulmonary fibrosis.