Which gene causes cystic fibrosis

However, if the mother and father each carry the recessive CFTR gene, the chances their children will develop CF are: 25 percent 1 in 4 the child will have CF 50 percent 1 in 2 the child will be a carrier but will not have CF 25 percent 1 in 4 the child will not be a carrier and will not have CF 1 These chances are the same each time two CF carriers have a child.

Figure 1. Carrier chart indicating gene inheritance probability. Why does this gene cause cystic fibrosis? Sign up for emails from Cystic-Fibrosis. Comments 0 comments. Reactions 0 reactions. View references caret icon. Sign up for emails Subscribe. Follow us Follow us on facebook Follow us on instagram Follow us on twitter. So the diagnosis comes as a surprise to parents.

Or that they passed the gene to the unborn baby at the same time. Genes are found on structures in the cells of the body called chromosomes. Each cell normally has 46 total chromosomes, or 23 pairs of chromosomes. The seventh pair of chromosomes has a gene called the CFTR cystic fibrosis transmembrane conductance regulator gene.

Changes mutations or errors in this gene are what cause CF. This gene is very large and complex. More than 1, different mutations in this gene have been found that cause CF. According to the Cystic Fibrosis Foundation, if you have no family history of CF, the risk of having a mutation in the gene for CF depends on your ethnic background:. Researchers are working on more effective drugs that can fold the protein into a more normal shape, move more chloride out of the cell, and reduce symptoms even further.

In addition to Fdel, missense mutations can sometimes cause processing problems and therefore can be considered processing mutations in those cases. The CFTR protein is shaped like a tunnel, or channel, with a gate. The cell can open the gate when chloride needs to flow through the channel.

Otherwise, the gate stays closed. Gating mutations lock the gate in the closed position so that chloride cannot get through. This enables chloride to move through the channel and reduces the symptoms of CF.

Watch the webcast starting at to learn more about CF gating mutations and how drugs, such as CFTR modulators, can help a person with one of these mutations. Sometimes, a change in one of the amino acids of CFTR means that even though the protein makes the right 3-D shape, it doesn't function as well as it should. In order for CFTR to work correctly, chloride has to be able to move quickly and smoothly through the protein's channel.

Some mutations change the shape of the inside of the channel so that chloride cannot move through as easily as it should. This kind of mutation is called a conduction mutation. Watch the webcast starting at to learn more about CF conduction mutations and how a drug such as a CFTR modulator might help a person with one of these mutations. Insufficient protein mutations result in a reduced amount of normal CFTR protein at the cell surface. This occurs for several reasons: a limited amount of CFTR protein is produced; only a small number of protein at the cell surface works correctly; or normal protein at the cell surface degrades too quickly, leaving small numbers of protein behind.

In each case, insufficient functional proteins at the cell surface produce only some, or residual, function of the chloride channel. Insufficient protein can be caused by several mutations, including missense and splice mutations. Cystic fibrosis CF is a genetic disease. This means that it is inherited. A child will be born with CF only if they inherit one CF gene from each parent. A person who has only one CF gene is called a CF carrier.

They are healthy and don't have the disease. But they are a carrier of the disease. A parent can be a CF carrier, and pass the CF gene on to their child. Once parents have had a child with CF, they have a 1 in 4 chance that each additional child will be born with CF.

This means there is a 3 out of 4 chance that additional children won't have CF.