Cystic Fibrosis: What causes it?

Cystic Fibrosis is a rare genetic disease that affects the lungs by clogging them up with dense and sticky mucous. This mucous causes coughing and shortness of breathe in patients affected with CF. Other symptoms of CF include salty tasting skin, poor growth/weight gain, and infertility in males.

But what causes Cystic Fibrosis? The answer is a genetic mutation in a specific gene in which the amino acid sequence differs from the typical sequence of normal channel protein. We must first understand the difference between a normally functioning gene and a mutated one. A normally functioning gene produces a channel protein that involves creating sweat and mucous. But sometimes a mutation occurs in which the gene does not function properly in creating sweat and mucous. This non-functioning allele is then passed on to the next generation. This isn’t harmful as long as the child has one working allele and one non-working allele. But if the child receives two nonfunctioning alleles, then he or she has Cystic Fibrosis.

Next we look at how the channel proteins manufactured from the faulty DNA cause the symptoms of coughing and shortness of breathe. We start off by examining how the protein functions in healthy people. In healthy people, the channel protein causes water to flow from the inside of a cell and into the lung cavity. This movement of water into the lungs dilutes the existing mucous causing it to become less dense. On the other hand, an abnormal or a mutated channel protein does not have the ability to embed itself in the membrane of the cell, which denies the protein from carrying out its function as a channel. This means that water does not get transported into the lung cavity and a buildup of dense mucous occurs causing the symptoms of coughing and shortness of breathe.