Cystic Fibrosis Case Study

These methods of genetic testing are accurate, as long as the genetic origin of the tested disease is known (Mahdieh & Rabbani, 2013), but their reliability is harmed by the fact that the results determine probability of diseases occurring (Holt, 2012). Even though a test accurately determines the presence of a given mutation, that mutation may only indicate a patient’s predisposition to developing symptoms. Since other genes or environmental factors may play a part in the tested disease, the results of testing aren’t entirely reliable for a conclusion of whether or not a patient will develop the disease.

CF happens because two parents have a defect in the CF transmembrane conductor regulator (CFTR) gene. If a child has only one parent that has a

Cystic Fibrosis is a disorder where the exocrine glands secrete abnormally thick mucus, leading to obstruction of the pancreas and chronic infections of the lungs, which usually cause death in childhood or early adulthood. Some mildly affected patients may survive longer. Doctors can diagnose the disease by testing the patients perspiration because people with Cystic Fibrosis have high amounts of salt in their perspiration. Those with respiratory infections are treated with antibiotics, with aerosols that relieve constriction of the airways and liquefy the thick mucus, and by physical therapy to help patients cough up the obstructing secretions. Patients with pancreatic insufficiency can take pancreatic enzymes with meals.

Cystic Fibrosis causes abnormal amounts of excessively thick and sticky mucus to develop within the lungs, airways and the digestive system. Due to the thick and sticky mucus, digestive functions in the pancreas are impaired and bacteria is trapped in the lungs causing recurrent lung infections. Cystic Fibrosis Victoria (2015) states that symptoms of Cystic Fibrosis can include:

What is Cystic Fibrosis? How does it affect people living with it? Cystic Fibrosis, also known as CF, is a life-threatening hereditary disease. It is inherited by a faulty cystic fibrosis transmembrane conductor (CFTR) gene from each parent (Kowalczyk, 2014, p. 74). This faulty gene makes a defective protein that does not work well and causes the body to produce sticky, thick mucus and very salty sweat("About CF: Causes, Signs & Symptoms of Cystic Fibrosis,"

Cystic Fibrosis is a genetic disease that causes the body’s lungs to generate a different type of mucus than a non-infected body would. The contaminated lungs will produce mucus that is thick and adhesive which clogs the lungs and leads to an unpleasant and abhorrent lung infection. CF also interferes with the pancreas, disallowing the digestive enzymes from breaking down and absorbing food in the intestine. This can result in low nutrition, feeble growth, excessive sweat production, difficulties in breathing, and sometimes lung disease. When producing extra sweat and mucus, the body loses salt. If too much salt is lost, it can cause abnormal heart rhythms, disturbance of minerals in the blood, and perhaps, shock.

A single person has two CFTR genes. They get one copy from each parent. If an adult or child has only one abnormal copy of this gene, they are a carrier of Cystic Fibrosis. A carrier simply means that they carry the trait for cystic fibrosis, and could give it to one of their children. If each parent gives a child one abnormal copy of the CFTR gene, this is when CF occurs. However if they only have one abnormal copy, the child becomes a carrier. When both parents are CF carriers, there is a 25% chance that their child will have Cystic Fibrosis.

The signs of cystic fibrosis varies from person to person. With this disease, some experience the severity of conditions at adolescence while others will not experience any symptoms until adulthood. The most prominent symptoms affect both the respiratory and digestive system.

“About 1 in 4,000 children in the United States are born with CF” (Crosta, 2009) and “one in every 3,600 children born in Canada [have] cystic fibrosis” ("Cystic fibrosis Canada," 2011). According to several resources a consensus has formed which proposes that people with northern European ancestry, specifically those that are white, are more likely to be carriers of the disease and thus more at risk of having children with the mutated gene. This risk is even more likely if the other parent of the child is a carrier. Another risk factor for CF is “family history, since the disease is hereditary it increases they likely hood of

Cystic fibrosis is a disorder that causes severe damage to the respiratory and digestive system. (Saint Francis Medical Center) It is caused by an inherited defective gene from both parents, specifically the CFTR gene, which causes the cells to overproduce mucus, digestive juices, and sweat. Normally, the fluids that are secreted are slippery and thin. However, with cystic fibrosis, the defect in the gene causes thick and sticky secretions. Instead of the secretions having lubricant properties, it clogs up tubes, passageways, and ducts, especially in the pancreas and lungs.

mutation is phenylalanine 508 known as delta F508. Delta F508 is a deletion of 3 nucleotides

In the respiratory system, the mucus causes breathing difficulties, frequent respiratory infections and eventually permanent lung damage. The mucus builds up providing bacteria with a place to flourish. The most common infection comes from a bacterium called Pseudomonas aeruginosa. The body's response to P. aeruginosa includes inflammation, which causes episodes of intense breathing problems (Pseudomonas Genome Project, 1998). Normally the body will get rid of excess mucus by coughing before it's a problem but with the thick mucus involved in CF the body has a harder time to get rid of the thicker mucus. Lung disease is the usual cause of death in most patients (National Institutes of Health, 1995). In the digestive system, mucus can block the supply of enzymes used to break down food. The result of the blockage of such enzymes is malnutrition. The patient will have an excessive appetite but will not experience any weight gain. What is also evident is a failure to grow, CF was often misdiagnosed vaguely as "failure to thrive" when physicians didn't know the reason for this poor growth. Sweating is also a problem in people with CF. One of the basic defects in CF is the faulty transport of sodium and chloride (salt). People with CF lose excessive amounts of salt when they sweat. This causes the natural balance of salt in the body to be off balance, which may cause abnormal heart rhythms (National Institutes of Health, 1995).

Cystic Fibrosis is a disease that affects the body in many ways throughout the patient's life. Newborns with Cystic Fibrosis may experience delayed growth, inability to gain weight, and salty-tasting skin ("Cystic," umm.edu 1). Older patients may be infertile, have recurring pancreatitis, and respiratory problems ("Cystic," umm.edu 2). Considering that these are just symptoms involving age, the full spectrum of ailments that afflict a patient with Cystic Fibrosis is far more taxing on a patient.

The objective of the project is to determine if I carry the allele at the TAS2R38 locus. In order to find that out, DNA was extracted from cells within the mouth. The DNA sample was quantified, amplified by PCR, ran through gel electrophoresis, purified and sequenced. The results for my DNA was not able to be determined through sequencing. The DNA samples of the class recorded that 62% of the participants were tasters (carries the allele at the TAS2R38 locus) and 38% of the participants were non-tasters (does not carry the allele at the TAS2R38 locus).

This is a great improvement over survival rate of the 1950s with the life expectancy of 1 year or less for cystic fibrosis patients. Unfortunately, since it is a recessive genetic disease, there are many men and women who are carriers of the disease without actually having the disease themselves. If each parent is a non-affected carrier of cystic fibrosis, there is only a 25 percent chance of having a non-affected, non-carrier child and 50 percent chance of having a child that is a non-affected carrier of cystic fibrosis. Unfortunately there is also a 25 percent chance of having a child affected by cystic fibrosis. This makes prenatal genetic screening very important.