Clonal Somatic Mutations in Chronic Lung Diseases Are Associated with Reduced Lung Function.

Overview

abstract

RATIONALE: Constantly exposed to the external environment and mutagens such as tobacco smoke, human lungs have one of the highest somatic mutation rates among all human organs. However, the relationship of these mutations to lung disease and function is not known. OBJECTIVES: To identify the prevalence and significance of clonal somatic mutations in chronic lung diseases. METHODS: We analyzed the clonal somatic mutations from 1,251 samples of normal and diseased non-cancerous lung tissue RNA-seq with paired whole genome sequencing from the Lung Tissue Research Consortium. We examined the association of somatic mutations with lung function, disease status and computationally deconvoluted cell types in the two of the most common diseases represented in our dataset, chronic obstructive pulmonary disease (COPD, 29%) and idiopathic pulmonary fibrosis (IPF, 13%). MEASUREMENTS AND MAIN RESULTS: Clonal somatic mutational burden was associated with reduced lung function in both COPD and IPF. We identified an increased prevalence of clonal somatic mutations in IPF compared to normal controls and COPD independent of age and smoking status. IPF clonal somatic mutations were enriched in disease-related and airway epithelial expressed genes such as MUC5B in IPF. Patients with MUC5B risk variant carrier had increased odds of developing somatic mutations of MUC5B that was explained by increased expression of MUC5B. CONCLUSIONS: Our identification of an increased prevalence of clonal somatic mutation in diseased lungs that correlates with airway epithelial gene expression and disease severity highlights for the first time the role of somatic mutational processes in lung disease genetics.