Cystic Fibrosis Gene Defect example essay topic

Cystic Fibrosis is the most common genetic disorder in the Caucasians population. It is a fatal inherited disorder of the lungs and digestive system. People that have a genetic disorder are born with it. The genetic defect causes a chemical error in all the cells in their bodies. In the children and adults with cystic fibrosis, a mistake in the single gene disables a type of protein that functions as an ion channel. This molecule regulates the balance of salt in a special type of cell that lines many of the body's glands.

All people with genetic disorders have inherited the defective genes from their parents. An inherited disease is not contagious. It cannot be caught as if it were a cold. Because cystic fibrosis is a genetic defect, people who have it cannot outgrow it. They must live with it throughout their lives. Today, people with cystic fibrosis have a life expectancy of about thirty years.

A person with cystic fibrosis has inherited two copies of a defective gene, one from each parent. Someone who has a copy of the defective gene is called a carrier. Carriers are healthy individuals who will never develop cystic fibrosis, but who can pass the gene on to their children. The gene that is defective in those with cystic fibrosis normally directs certain cells in the body to make a salt-regulating protein called the cystic fibrosis transmembrane conductance regulator (CFTR). Because cystic fibrosis carriers have one normal copy of the CFTR gene they can generate enough normal CFTR protein to keep their cells healthy. According to the Cystic Fibrosis Foundation, there are currently about 30,000 people in the United States that have cystic fibrosis.

In the United States almost one person in thirty carries the gene for cystic fibrosis, which means that about ten million Americans have one copy of the defective gene. It is estimated that one per 2000 live births will be affected by this inherited disorder. Genes provide cells with a detailed set of instructions with a chemical sequence of a molecule called DNA. DNA acts like a long tape with all the information that a cell needs to make the proteins necessary for it to develop into a cell and to carry out its specific function. Scientists estimate that 60,000 to 100,000 genes tell cells how to operate and grow. Humans have twenty-three pairs of chromosomes - one set of twenty-three from each parent.

If both parents have two normal copies of the CFTR gene, none of their children can get cystic fibrosis. If both parents have two defective CFTR genes the child has a one hundred percent chance of having cystic fibrosis. If one parent has cystic fibrosis and the other has two normal copies of the CFTR gene, the child has a one hundred percent chance of being a carrier. If one parent has CF and the other is a carrier, the child has a fifty percent chance of having CF or being a carrier. Paul M. Quinton of the University of California at Riverside found that the epithelia lining the ducts of sweat glands failed to take up chloride efficiently from the cavity or lumen of the glands. This finding explained why people with cystic fibrosis have unusually salty sweat.

Sweat is usually produced at the base of a sweat gland. In a healthy person it flows to the surface of the skin through a narrow duct. Usually sweat is a solution that has a lot of chloride ions and sodium. Salt is made of chloride ions and sodium. As the fluid passes through the duct the ions escape to the epithelium leaving the water behind. All the sweat that im merges is to cool the skin surface and is slightly salty.

In a person with cystic fibrosis, the absorption from the duct causes sweat to retain excess sodium and chloride and is very salty in a person that has cystic fibrosis. The mucus in a person with cystic fibrosis is thicker and stickier than that of a healthy person. Because the mucus is thicker in the lungs of a person with cystic fibrosis it clogs the airways. Small airways become blocked by mucus. This causes the lungs to lose some of their capacity.

For people with cystic fibrosis, this airway obstruction causes distress such as coughing, wheezing and an increased chance for lung infections. Pneumonia and bronchitis are common problems in people that have cystic fibrosis. The pancreas plays an important part in the digestion of food because of the enzymes it produces. In the majority of people with cystic fibrosis, mucus clogs the ducts in the pancreas which causes proteins and fats to leave the body without being digested. This means they do not get all of the nutrition that a normal person gets when they eat.

This causes them not to gain weight at a normal rate. Doctors have the capabilities now to test babies before they are born. The doctors may choose to perform either an amniocentesis or chorionic villus biopsy. In an amniocentesis, cells from the fluid surrounding the baby in the mother's womb, which is called amniotic fluid, are tested to see if the cystic fibrosis gene is present. In chorionic villus biopsy, cells from the tissue that will eventually form the placenta are tested for the cystic fibrosis gene. Technicians can test the blood of a newborn to see if their protein level is too high.

This test is called the immunoreactive trypsinogen test (IRT) test. Tests have shown that newborns with cystic fibrosis have a much higher level of the specific protein called trypsinogen than normal. This test also measures the level of pancreatic enzymes. Doctors usually rely heavily on the sweat test. It has proven to be very reliable. The doctor places electrodes that are surrounded by a gauze pad soaked with a drug called piolcarpine on the forearm of the child being tested and wraps the area in plastic.

The technician uses a very weak electric current to drive the pilocarpine into the skin. The harmless drug stimulates the sweat glands to produce sweat. The technician then removes the electrodes and covers the stimulated area with an absorbent piece of filter paper to collect the sweat. After 30 minutes, the technician removes the filter paper and sends it to the lab, where the levels of chloride in the child's sweat are measured. Children with cystic fibrosis have a level two to five times the normal amount of salt in their sweat. Physiotherapy is the use of different body positions to achieve drainage of the mucus for a particular area of the lungs by using gravity.

It also increases the flow of air to many parts of the lungs. Physiotherapy is very important for people that have cystic fibrosis to help keep the lungs clear. There are four different techniques in physiotherapy. These are breathing techniques, chest clapping, chest shaking and flutter therapy. The purpose of chest physiotherapy is to prevent lung secretions from building up in small air tubes in the lungs so infections are not as likely. Since the mucus produced by the lungs in a person with cystic fibrosis has less water than it should, it is stickier and cannot be coughed up or swallowed without the help of treatments like physiotherapy.

Pancreatic enzyme insufficiency is the most common problem in cystic fibrosis. The cystic fibrosis gene defect results in a decrease of water content of the pancreatic secretions. The increase of thick secretions causes obstruction and can cause damage to the pancreas. There will be an unavoidable deterioration of the pancreas due to high concentrations of enzymes which remain there instead of being delivered to the intestines. Without pancreatic enzymes, fats, proteins and carbohydrates, nutrients cannot be digested or absorbed. Pancreatic enzyme insufficiency is treated with pancreatic enzyme supplements.

These should be taken with every meal or snack, including milk. These supplements are capsules. For infants or younger children the capsules can be opened and poured directly into the mouth. The dose varies on the severity of the patient. Physical activity is very important to keeping people with cystic fibrosis healthy.

Exercises should be encouraged at an early age so the children can grow up with as much activity as possible. Exercise is an essential part of treatment because it helps maintain strength, mobility and promises a better image of the body. The most beneficial exercises for people with cystic fibrosis is any exercise that will get you out of breath such as swimming, running, football or tennis. Exercise is medically beneficial because it offers better clearance of the secretions and can reduce possible infections. Tobi therapy is the inhalation of an antibiotic called tobramycin. About 300 milligrams of tobramycin is given in a single inhalation therapy session to clear a lung infection called psedumonas aeruginosa.

This can be inhaled at home twice a day for twenty-eight days. The patient then stops taking the drug for twenty-eight days for three on-off cycles over twenty-four weeks. Tobramycin can be taken orally but is more effective if inhaled. When all treatments have been used and a person has reached what is called the end-stage pulmonary disease, lung and / or heart transplants are considered for the patient. A lot of cystic fibrosis patients die at an early age from pulmonary complications. If a person is lucky enough to make it to the donor list and receive a lung their chances for survival are still not good.

Only 124 children with cystic fibrosis were accepted for lung transplants between 1988 and 1998. Some of the criteria that have to be met in order to be put on a donor list are a life expectancy of less than two years with a poor quality of life. Therefore, they are already in very poor health before even being considered for a transplant. Of the 124 children on the donor list, sixty-eight died while waiting for the donor organ to become available. Cystic fibrosis is not curable at this time.

With the improved treatment provided.