What is the genetic cause of Cystic Fibrosis?

Cystic Fibrosis is caused by a point mutation in the CFTR gene. This gene, which is located on chromosome 7, codes for a protein that functions as a chloride channel in epithelial cells. The most common mutation associated with Cystic Fibrosis is a specific deletion of three nucleotides, which results in the loss of a single amino acid (phenylalanine) in the protein structure.

This disruption in the CFTR protein leads to the production of thick and sticky mucus in various organs, particularly the lungs and digestive system, which is the hallmark of the disease. The nature of this mutation is such that it alters a single nucleotide sequence in the DNA, making it a point mutation rather than a chromosomal disorder or a larger genetic aberration like the deletion of an entire chromosome or the addition of an extra chromosome. Consequently, understanding that Cystic Fibrosis is linked to a specific, localized genetic mutation clarifies the biological basis of the disorder.