Gene Defects In Cystic Fibrosis example essay topic

Cystic Fibrosis is a severe hereditary disease that infects the lungs, digestive system, sweat glands and male fertility. The name Cystic Fibrosis derives from the Fibrous scar tissue that develops in the pancreas. First recognized in 1938, cystic fibrosis is generalized as an recessive disorder of the exocrine glands. About one in every 2500 Caucasians is affected, and one in 25 is a carrier of the cystic fibrosis gene. Cystic fibrosis is the most common fatal hereditary disorder of Caucasians in the United States and is the most common cause of chronic lung disease in children and young adults. Approximately 38,000 children and young adults in the United States today.

About 3,000 babies are born with cystic fibrosis every year. Several decades ago many children with cystic fibrosis died by the age of 2. Today, about half of the people with cystic fibrosis live past the age of 31. That number is expected to grow with the continuing success of modern treatment. Because cystic fibrosis is a genetic disease, it is caused by a defect in the person genes.

These genes form the nucleus of all the body's cells and control cell function, serving as the blueprint for the production of proteins (Gale 876). The defective gene that causes cystic fibrosis is called cystic fibrosis trans membrane conductance regulator, or for short, CFTR. It is the protein responsible for regulating chloride movement across cells in some tissues. When a person has two defective copies of the CFTR gene, cystic fibrosis is the result (Gale 876). There are over 500 known defects in the CFTR gene that can trigger cystic fibrosis (CF). The gene defects in cystic fibrosis are called point mutations.

As a result, the CFTR protein made from the CFTR gene, is made incorrectly and cannot perform its function properly. The CFTR protein helps produce mucus which is a mixture of salts, waters, sugars and proteins. The role of the CFTR protein is to allow chloride ions to exit the mucus producing cells. It helps to keep mucus from becoming to thick and sluggish, allowing the mucus to be moved steadily. In CF, the CFTR protein cannot do its job properly, and cannot allow chloride ions out of the mucus producing cells. The mucus becomes thick and can lead to malnutrition and emphysema (Gale 878) Approximately one in every 25 caucasians is a carrier CF gene, while only one in 17,000 African Americans and one in 30,000 Asian American are carriers.

Few people know they are carriers unless they have family history of the disease. Two white Americans with no family history of CF have a one in 2500 chance of having a child with CF (Berhow 245). The most severe effects of cystic fibrosis are seen in two body systems; the gastrointestinal (digestive) system and the respiratory tract. CF also affects male fertility and the sweat glands.

Effects in the digestive system are often the first to appear. About fifteen percent of babies who inherit CF have me conium ileus at birth. Meconium is the first dark stool that the baby produces after birth. Ileus is an obstruction of the digestive tract (Claymen 437). Meconium, the dark green stool, is thick and sticky, due to the presence of thickened mucus from the intestinal glands. Meconium ileus causes abdominal swelling and vomiting.

The presence of me conium ileus is highly indicative of CF. Babies who have me conium ileus almost always develop symptoms of CF. The respiratory tract includes the nose, the throat and the windpipe. Nasal polyps, Bronchitis, pneumonia and shortness of breath are frequent recurring respiratory problems in someone with CF (Claymen 438) The first symptom of CF in infants without me conium ileus, is often poor weight gain at 4 to 6 weeks old (Berhow 246) Inadequate amount of secretions essential for proper digestion of fats and proteins lead to poor digestion in 90 percent of babies with CF. Growth of the infant is slow despite normal appetite.

The baby is thin and has flabby muscles. The baby has frequent, bulky, foul smelling oily stools. Diagnosis of CF in young adults should be suspected if they have a history of chronic lung disease, pancreatitis or infertility. Teen-a gers often show very slowed growth, delayed puberty and decreasing physical endurance. Young adults with CF, are heavily plagued with infection. Recurring bronchitis and pneumonia can substantially weaken lungs and gradually destroy them.

CF also effects the sexual reproduction of young adults. The majority of adults with CF have impaired reproductive functions. Ninety-eight percent of males have very little to no sperm count at all (Tierney 203). Females with CF, cervical secretions are too thick causing decreased fertility.

They also have a higher likelihood of complications during pregnancy (Tierney 203). The severity of CF varies greatly from person to person. Age doesn't matter, it is mainly determined largely by how much the lungs are affected. However, deterioration is inevitable and leads to death. But the outlook has improved over the past 25 years. Treatments can now postpone some of the changes which the lungs go through during CF.

Today, more then half of people with CF live longer then the age of 31. (Tierney 203). Treatments such as Antibiotics and Processes like therapy and lung transplantation hold great promise for treating CF. Antibiotics such as Aerosolized tablets containing pancreatic enzymes. Therapy includes prevention and treatment of lung problems, good nutrition, physical activity, psychologic and social support (Claymen 439). Lung transplantation is currently the only definitive treatment.

It has become increasingly popular among people with CF. Double lung and heart lung transplantation is accumulating rapidly (Cotran 336). While their is no cure for CF, with the growing life expectancy and the treatments that help lengthen life, people who suffer from CF life is improving. A generation ago, most children with CF died within a few years. Mo dren treatment has extended life expectancy. Children with CF might be able to live into adulthood.

Despite their many problems and personal setbacks, people with CF attend school and work. They are able to lead normal lives. Because of better and earlier treatment, people born in the future with CF may be able to live a normal life without fearing they might live to see the next day.

Bibliography

Claymen, Charles B. The American Medical Association Family Medical Guide. New York: Random House., 1994 Cotran, Ramis S.
Kumar, Vinay. Robbins, Stanley L. Pathologic Basis of Disease. Philadelphia, Pa: WB Saunders Company., 1994 Tierney, Lawrence M.
Mcphee, Stephen J. Papadakis, Maxine A. Current Medical Diagnosis and Treatment. Stamford, CT: Appleton & Lange., 1997 Gale, James.
The Encyclopedia of Genetic Disorders and Birth Defects. New York: Oxford., 1991 Berhow, Robert.
The Merck Manual of Medical Information. Whitehouse Station, NJ: Merk & Co Inc., 1997.