Cystic Fibrosis


About 1 out of 201 Caucasian people carries at least one of the fatal defective genes that cause cystic fibrosis, CF, or mucoviscidosis (in Europe) although carriers don't show any signs of the disease. Therefore, 10 million2 people carry the defective gene and aren't aware of it. Consequently, it makes it one of the most common genetic defect in the United States.

CF is a autosomal recessive gene. That means that it may, but doesn't always skip generations. In order to get this disease, both parents must be carriers. If one parent has CF and the other one is not a carrier than there is a 100% chance that their child will be a carrier. If one parent has CF and the other is a carrier than the child has a 50% chance of having CF and a 50% chance of just being a carrier. If both parents are carriers than their child will have a 25% of having CF, a 50% chance of being a carrier and a 25% chance of not being affected. CF is common in both males and females, there is not a specific sex that it is more common in.

How does a person know if they have CF? There are many symptoms to this deadly disease including: salty tasting skin, constant coughing, large amounts of mucus, trouble gaining weight, frequent greasy, foul smelling bowel, growths in the nose (nasal polyps) and clubbed or enlarged fingertips and toe tips is another symptom. Now there are many tests that can be done to find put if a person has CF.

One way which CF can be detected is to observe the symptoms. A person doesn't need to have all the symptoms in order to have cystic fibrosis, but they usually show most of them. Another way are different genetic testing. Doctors can now do genetic testing for CF, but about 10 years ago they couldn't. In 1989, the location where the of the defective gene on chromosome number 7 is was discovered by Francis S. Collins from University of Michigan. Tests can now be taken to see if an unborn child is infected with CF such tests are amniocentesis, chronic villus biopsy3 and a removal of cells from the embryo during invitro.

Many years ago, New York4 had a heat wave, and the hospitals became overwhelmed with dehydrated CF children. These children became dehydrated much quicker than children without the disorder. Thus eventually resulting in the formation of the sweat test which is now the standard test. Doctors place a pad or filter paper on a patients arm or back. A chemical called Pilocarpine, makes a burst of electricity to produce more sweat. Then the pad is wrapped in plastic and is sent to a lab to get analyzed. The doctors then would look for a high chloride content in the sweat. Another test is a blood test that is administered 3 days after a baby is born. It is called Immunoreactive Trypsinogen5 if that comes back positive it is then double checked with a sweat test.

Furthermore CF causes the sweat glands to release about 5 times6 as much salt as a normal person would. This is why the skin of a CF patients may taste salty. They don't sweat more, but when they perspire more salt is excreted. This causes the person to dehydrate.

CF is a disorder that causes the body to produce larger amount of mucus than normal. In a normal person, mucus in the lungs helps get rid of germs and bacteria in the air. In a CF patients the lungs become covered with a sticky mucus that is hard to remove and promotes infection from bacteria. Over time infections cause the lungs to become extremely weak, therefore ending in respiratory failure.

Also CF affects the digestive tract. The overproduction of mucus causes the pancreatic ducts to be clogged. Therefore preventing necessary enzymes to digest fats and proteins. Without those enzymes CF patients can't gain weight. The undigested proteins and fats pass right through the body creating smelly bowel. In some cases this malnutrition causes people to die when they are only children. Also it is more common for people with cystic fibrosis to develop digestive tract cancer7. High levels of the protein CFTR (which the gene makes) are found in the digestive tissues. Doctors explain this increased risk of cancer because CF induces change