In the lungs the mucus stops the air passage from drying and stops the bacteria and takes it out of the body. However in a person with cystic fibrosis they still produce the mucus, but the mucus is thick and sticky. This clogs the passage ways. It still stops the bacteria but it doesn't take it out of the body this causes infections. In the lungs the mucus produced blocks the bronchial tubes. This causes infections because of the bacteria not leaving the lungs. The lungs become filled with little cysts containing pus. The small, delicate elastic tissue in the air sacs is replaced with a hard, rigid tissue called fibrin, hence the cystic fibrosis. In the pancreas, the mucus blocks the path between the pancreas and the intestines. This blocks the enzymes going to the intestines to breakup the food to get vitamins and nutrients. People with cystic fibrosis tend to have a high salt content in the body sweat.
Most people with cystic fibrosis are born healthy but gradually show sign of the disease when they are young. They develop a chronic cough, wheezing and respiratory infections. Other symptoms are diarrhea, pneumonia, salty skin and poor growth.
A person gets cystic fibrosis when he/she inherits the mutated cystic fibrosis transmembrane regular gene, or CFTR for short from each parent. The CFTR is in chromosome number 7. If the child receives a mutated CFTR chromosome 7 gene from both parents he/she will develop cystic fibrosis. Because cystic fibrosis is a recessive disorder it needs the two copies from both the parents for CF to appear in the phenotype. Here is a punnet square to show how a child might get CF.
When parents are carriers.
Genotype of parents: M=Cc F=Cc.
C=CFTR c=mutated CFTR.
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Possible genotypes: CC-%25, Cc-%50, cc-%25.
Possible phenotypes: Normal-%25, Carrier-%50, CF-%25.
The chances of having a child with CF when both parents are carries are %25.
When you or your partner has CF and the other is a carrier:.