Could a defective epithelial sodium channel lead to bronchiectasis

Respir Res. 2008 May 28;9(1):46. doi: 10.1186/1465-9921-9-46.


Background: Bronchiectasis is defined as a permanent dilation of the airways arising from chronic bronchial inflammation/infection. In 50% of cases, no etiology can be identified. Recently, the role of the epithelial sodium channel ENaC has been pointed out in the pathophysiology of cystic fibrosis, a disease due to mutations in the CFTR gene and causing bronchiectasis in the airways. Moreover, it was found that transgenic mice overexpressing ENaCbeta present cystic fibrosis-like lung disease symptoms. Our aim was to evaluate if a defective ENaC protein could be involved in the development of bronchiectasis.

Methods: We extensively analysed ENaCbeta and gamma genes in 55 patients with idiopathic bronchiectasis and without two mutations in the coding regions of CFTR. Thirty-eight patients presented functional abnormalities suggesting impaired sodium transport (abnormal sweat chloride concentration or nasal potential difference measurement), and 17 had no such evidence.

Results: Sequencing of the exons and flanking introns of the ENaCbeta and gamma gene identified five different amino-acid changes (p.Ser82Cys, p.Pro369Thr, p.Asn288Ser in ENaCbeta ; and p.Gly183Ser, p.Glu197Lys in ENaCgamma) in heterozygous state in 8 patients. The p.Ser82Cys amino-acid change was found in 3 unrelated patients who were also heterozygous for a CFTR mutation or variant (1 p.F508del, 1 IVS8-5T, and 1 IVS8-5T:1716G>A (p.E528E)). The other mutations were found in patients without CFTR mutation, the p.Glu197Lys mutation in 2 patients and the other variants in single patients. Among the 8 patients bearing an ENaC mutation, 5 had functional abnormalities suggesting impaired sodium transport.

Conclusion: Our results suggest that several variants in ENaCbeta and gamma genes might be deleterious for ENaC function and lead to bronchiectasis, especially in patients who are trans-heterozygotes for ENaCbeta/CFTR mutations or variants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Bronchiectasis / genetics*
  • Case-Control Studies
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Epithelial Sodium Channels / genetics*
  • Female
  • Genetic Predisposition to Disease / genetics
  • Humans
  • Ion Transport / genetics
  • Male
  • Middle Aged
  • Mutation, Missense / genetics*
  • Polymorphism, Genetic / genetics
  • Protein Subunits / genetics
  • Sodium / metabolism


  • Epithelial Sodium Channels
  • Protein Subunits
  • Cystic Fibrosis Transmembrane Conductance Regulator
  • Sodium