Shelby Parker sits in the lotus position in the middle of a hospital bed, her slender arms resting on the pillow in her lap. Cystic fibrosis is catching up with her. At 23 years old Shelby stands at five foot two inches and weighs seventy pounds. She seems impossibly thin, her limbs are so frail it’s a wonder she can lift a glass of water.
Just a year ago, Shelby was a fulltime college student, but now she spends day and night connected to an oxygen tank. A hose runs into her nose, another pumps intravenous antibiotics into her arm. An infection almost killed her in January, and nothing short of a lung transplant will save her.
A tiny doe-eyed women with a child’s voice, Shelby is in a life and death show down with her disease. Her lungs, scarred by repeated infections, are failing. Ten years ago, death would have loomed certain. Today there is hope. Just a few miles from where Shelby waits, doctors at the University of North Carolina are leading a national effort to cure cystic fibrosis by repairing the faulty gene that causes the disease. But that prospect is still very far off.
For Shelby, the only real hope lies in the hands her doctors who have the power to remove her weak, scarred lungs and replace them with a healthy set.
Cystic Fibrosis is a disease caused by an inherited genetic defect. It is not contagious, yet about one in twenty-three people in the United States carry at least one defective gene. This statistic makes cystic fibrosis the most common genetic defect of its severity in the country.
For many, cystic fibrosis used to be known as a childhood disease, and to some it still is. Just thirty years ago, the median survival age was only eight, but thanks to medical advances, life expectancy is now just under forty for cystic fibrosis patients. Today there are an alarming number of adults with this disease who face an added set of problems such as: finding health insurance, going to college, getting a job, and building permanent relationships- all while keeping up physical therapy and medications.
For many years the causes of cystic fibrosis were a mystery, but recent advances in biology have made the reasons much more clear. Humans have a gene encoded in their DNA, which manufactures a special protein called CFTR. This protein controls the flow of chloride ions across the cell membrane. Each gene is made up of two alleles. A person only needs one correctly encoded allele for normal CFTR production. However, if both alleles are defective, the person will have cystic fibrosis. Those with a single defective allele are called carriers.
A correctly operating chloride channel is important for the functioning of many bodily systems. The improper regulation in cystic fibrosis patients, therefore, affects a wide range of organs in the body.
The sweat glands of people with this disease release salt about five times more concentrated than normal sweat glands release. This is the basis for the sweat test, a common way for checking for cystic fibrosis. It examines the sweat for chloride and/or sodium. This is also why people with cystic fibrosis have salty skin.
Clogging of pancreatic ducts leads to an enzyme deficiency in the intestines of people with cystic fibrosis. Without these enzymes, humans can not efficiently digest fats and proteins. The fats and proteins pass straight through the digestive system and produce greasy, smelly bowel movements. Far worse, the resulting malnutrition used to cause people with cystic fibrosis to die in childhood. There are now pancreatic enzyme supplements, which allows patients to eat normal foods while correcting this problem.
Even though the pancreas can not deliver the enzymes to the small intestines, it doesn’t stop producing them. Over time, this would lead to irreversible damage to the pancreas impairing its ability to produce insulin. This usually causes some type of diabetes.
The liver also suffers from gradual deterioration. There has been some work on the synthesis of artificial bile salts, but this work is too preliminary to draw any conclusions at this time.
People with cystic fibrosis absorb food less efficiently than normal adults do. Enzyme supplements will usually take care of this, but
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