Cystic Fibrosis- Option 2
Justin Jang and Junior Suwannapeng
Jasper High School
Cystic fibrosis is an autosomal (not sex linked), hereditary disease caused by a mutation in the gene called the cystic fibrosis transmembrane conductance regulator gene, or the CFTR gene. This CFTR gene belongs to a group of genes called ABC (ATP-binding cassette). These are transport molecules for molecules such as phosphate, glucose, chloride, and peptides. Specifically for the CFTR gene, the molecules transported are chloride and sodium. The CFTR protein, which is created by the CFTR gene, has a molecular weight of 168,173 daltons and in length, is 1480 amino acids long. This variation in genes is located in chromosome 7 of humans. Because most people have two of the CFTR gene which creates the CFTR proteins, a person can be completely healthy with a mutation in the gene, as long as at least one of these genes are unchanged from the normal state. Without the cystic fibrosis variation of the CFTR gene, the CFTR proteins created by the gene act as a channel protein which can be found in the membranes of cells which line the passageways of organs such as the pancreas, lungs, and intestines. The CFTR protein can be modified in numerous ways to give the host cystic fibrosis; in fact, over 1000 transformations of the CFTR gene have been recognized. One of the most common of these mutations is a deletion of a single amino acid from the long chain of 1480 in the CFTR protein. This causes a breakdown of the channel made with the missing amino acid, which means that it never transports chloride ions, like it was made to do, because it never reaches the cell membrane. This mutation is delta F508, because the deletion occurs at position 508 on the CFTR protein. These sorts of mutations work to deteriorate and destroy the efficiency of the CFTR protein by changing or replacing parts of the protein’s amino acid order. This order chooses the way that the protein is folded, and if this order is changed or altered, the way that the protein will also be modified, causing the protein to not be able to work. In this case, the protein is a protein channel inside a membrane, and if folded improperly, the molecules that would normally pass through it are not able to, which means that the structure has failed to do its task, which is the transport of chloride and sodium across epithelium (tissues). This failure is caused by the altered fold of the protein, because proteins function only when the proteins are folded perfectly. When folded improperly, the substances for which the protein was made cannot fit through the protein channel, and so cannot pass through it.
The phenotype or physical appearance of anyone with the autoimmune disease cystic fibrosis varies, as there are multiple possibilities and combinations, but have many recurring traits. Some of these visible traits include Delayed growth, failure during childhood to gain weight in a “normal” manner, bursts of weight loss, copious and unnatural production of phlegm, and scarring. Most of the phenotypes of cystic fibrosis do not show is a visible manner in the very early stages of human life. However, about 20% of babies with CF will be born with meconium ileus, which is a severe intestinal obstruction. The lack of certain transport molecules also prevents nutrient absorption, which causes a huge appetite.
Cystic fibrosis was discovered in the 1930s by the Bohemian pathologist Carl von Rokitansky, who made the first description of the disease as part of a report about a death of a fetus. In 1938, Dorothy Andersen M.D. wrote the first comprehensive report on cystic fibrosis and also named it, referring to the cysts in the pancreas of children and an elevated amount of fibrous tissue. In 1955 a group of parents founded the Cystic Fibrosis Foundation, which later became the National CF research Foundation in 1955 as well. In 1980,b The foundation created the Research Development Program, which is...
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