Gene mutation in cystic fibrosis
Mucoviscidosis (also: cystic fibrosis, CF) is an incurable metabolic disease. It is a genetic disease that follows an autosomal recessive inheritance. Every person has a double set of chromosomes (one from the father and one from the mother) with genes distributed on them, i.e. there are two genes for each trait.
Autosomal-recessive means that the disease only manifests itself if both genes have the defect for cystic fibrosis, so both father and mother must have been carriers of the diseased gene and passed it on to their child. Those who only have one mutated gene are not themselves ill, but can pass the disease on to their children. In cystic fibrosis, the so-called CFTR gene located on chromosome 7 is altered (mutated).
More than 1000 mutations have been proven to cause cystic fibrosis, but the most common is mutation ?F508, which lacks the amino acid phenylalanine in the gene. This accounts for about 70% of the diseases. The CFTR gene codes for a chloride channel.
As a result of the gene defect, these chloride channels are only produced incorrectly by the body, which severely impairs the function of the channels. They are located in the cell membranes of various organs and are normally continuous for chloride ions, which means that they are partly responsible for the fluid content of the secretions of various tissues. However, because the chloride channels built into cystic fibrosis patients no longer function properly, the secretion is not sufficiently enriched with fluid and viscous, viscous secretions are formed.
Organs that are particularly affected are the pancreas and the lungs, but CFTR channels are also found in the small intestine, the bile ducts, sweat glands and gonads. The viscous secretion has slower flow rates and therefore leads, for example, to bronchial tubes in the lungs becoming stuck together or the ducts of glands becoming blocked. As a result, the organs are significantly restricted in their functions and are also sometimes more susceptible to infections. Ultimately, this results in the very different symptoms of cystic fibrosis.
