CF VS CF Gene

[Guest guest]

Jean,

I apologize for the terminology. Genetic testing involves many terms that

are difficult to explain or find an alternative for. Here is another try.

It is important to note that genes themselves do not cause disease—genetic

disorders are caused by mutations that make a gene function improperly. For

example, when people say that someone has “the cystic fibrosis gene,†they

are

usually referring to a mutated version of the CTFR gene, which causes the

disease. All people, including those without cystic fibrosis, have a version of

the CFTR gene.

A mutation is a permanent change in the DNA sequence of a gene. Sometimes

mutations in DNA can cause changes in the way a cell behaves. This is because

genes contain the instructions necessary for a cell to work. If some of the

instructions to the cell are wrong, then the cell may not know what it is

supposed to do!

A defective CFTR gene causes the body to produce an abnormally thick, sticky

mucus that clogs the lungs and leads to life-threatening lung infections.

These thick secretions also obstruct the pancreas, preventing digestive enzymes

from reaching the intestines to help break down and absorb food.

How this occurs is that the CFTR gene provides instructions for making a

protein called the cystic fibrosis transmembrane conductance regulator. This

protein functions as a channel across the cell membrane. Such channels are found

in tissues that produce mucus, sweat, saliva, tears, and digestive enzymes.

Chloride, a part of salt, is transported through the channels in response to

cell signals. The transport of chloride helps control the movement of water in

tissues and keeps mucous and other secretions thin. This gene also

regulates how sodium crosses cell membranes. Making sure that sodium and

chloride

move across cell membranes normally is needed to make sure that the lungs and

pancreas function normally.

More than 10 million Americans are unknowing, symptomless carriers of the

defective CF gene. An individual must inherit two defective CF genes—one from

each parent—to have CF. Each time two carriers conceive, there is a 25 percent

chance that their child will have CF; a 50 percent chance that the child will

be a carrier of the CF gene; and a 25 percent chance that the child will be

a non-carrier.

Karyn E. , RN

Executive Director, PAI

Indianapolis, Indiana