CF is caused by mutations in the CFTR gene (Cystic Fibrosis Transmembrane Conductance Regulator), which encodes a protein that functions as a chloride channel in epithelial cells. The most common mutation is the deletion of three nucleotides, resulting in the loss of the amino acid phenylalanine at position 508 (ΔF508). This defective protein leads to impaired chloride ion transport across cell membranes.
