While cystic fibrosis transmembrane conductance regulator deficiency had been shown to contribute to the physiopathology of cigarette-induced diseases such as chronic bronchitis and COPD30, 31, most studies confirm that Na+ reabsorption is also a key factor in maintaining fluid balance in the lung, and ENaC plays a crucial role in Na+ reabsorption32, 33, 34. The gene discussed is CFTR; the disease is hyperinsulinemic hypoglycemia, familial, 4.