How can small change in the DNA of a cystic fibrosis patient cause the disease?

Cystic fibrosis is primarily caused by mutations in the CFTR gene, which encodes a protein responsible for regulating salt and water movement across cell membranes. A small change, such as a deletion of three nucleotides, can lead to the production of a malfunctioning protein that disrupts this regulation. This dysfunction results in thick, sticky mucus buildup in various organs, particularly the lungs and pancreas, leading to the characteristic symptoms of the disease. Thus, even a minor alteration in the DNA can have significant physiological consequences.