Cystic fibrosis is caused by mutations in a specific gene called the CFTR gene, which stands for cystic fibrosis transmembrane conductance regulator. This gene is responsible for producing a protein that controls the movement of salt and water in and out of cells throughout the body. When this gene has certain mutations, it disrupts how this protein works, leading to problems with ion transport across cell membranes.
Normally, the CFTR protein acts like a channel that helps chloride ions pass through cell membranes. This process regulates the balance of salt and water on surfaces like those lining the lungs, pancreas, and other organs. When mutations impair or block this channel’s function, thick and sticky mucus builds up because water does not move properly to keep mucus thin and flowing smoothly.
The most common mutation causing cystic fibrosis is called ΔF508 (delta F508), where a small piece of the CFTR protein is missing due to deletion of an amino acid called phenylalanine at position 508. This mutation causes defective processing of the CFTR protein so it never reaches its proper place on cell surfaces or functions correctly once there.
There are actually over 2,000 known mutations in the CFTR gene that can cause cystic fibrosis or related symptoms. These mutations affect different parts or steps involved in making or operating the CFTR protein — from how it’s made inside cells to how stable it remains once formed. Because these defects vary widely among individuals with cystic fibrosis, symptoms can also differ significantly.
Cystic fibrosis follows an autosomal recessive inheritance pattern. This means a person must inherit two faulty copies of the CFTR gene—one from each parent—to develop full-blown disease symptoms. If someone inherits only one mutated copy but has one normal copy as well, they are considered carriers without having symptoms themselves but can pass on that faulty gene to their children.
When both parents carry defective versions of this gene:
– Each child has a 25% chance of inheriting two mutated copies (and thus developing cystic fibrosis).
– A 50% chance of being a carrier like their parents (one mutated copy).
– And a 25% chance of inheriting two normal copies without any risk for disease.
Because these genetic changes affect ion channels regulating salt movement across epithelial cells lining organs such as lungs and pancreas:
– The lungs produce thick mucus that clogs airways leading to chronic infections and inflammation.
– The pancreas gets blocked by thick secretions preventing digestive enzymes from reaching intestines properly causing malnutrition issues.
Other organs including liver, intestines, sweat glands also get affected due to abnormal secretions caused by dysfunctional CFTR proteins.
This genetic defect is present from birth; no environmental factors cause cystic fibrosis directly though environment influences severity over time through infections or lifestyle factors affecting lung health.
In summary: Cystic fibrosis arises because inherited mutations disrupt how chloride ions move through cells via defective CFTR proteins encoded by mutated genes inherited recessively from both parents — resulting in thickened mucus buildup damaging multiple organ systems primarily lungs and digestive tract throughout life.
