Cystic fibrosis is a hereditary disease, which means that it’s passed on through the genes of parents. As a hereditary disease, cystic fibrosis has a clear genetic cause, and though more research is being done on specific cystic fibrosis causes, the medical community already has a solid grasp on how the disease is passed on and how it develops.
Genetic Cystic Fibrosis Causes
Those who suffer from cystic fibrosis have large amounts of mucus in their digestive, reproductive, and respiratory systems. This mucus is more abundant and thicker than mucus in those without cystic fibrosis, and it impedes or prevents the normal functioning of many of the body’s organs including the lungs, pancreas, ovaries, testis, intestines, and liver. Cystic fibrosis also affects how a body sweats, and those with the disease typically have much saltier sweat than others.
This overabundance of mucus is caused by a genetic defect of the CFTR gene. The CFTR gene controls the production of a protein that is responsible for the movement of water and salt into, out of, and between your body’s cells. Because of the genetic defect, your body creates a different type of protein which results in a mucus that is thick, sticky, and salty.
There are numerous defects of the CFTR gene, and though some defects will have little effect on the production of the protein and the creation of mucus, there are many defects that are very serious. Scientists have already identified over 1,900 different genetic defects of the CFTR gene that cause cystic fibrosis. Some of these defects are worse than others, and depending on the defects in a person’s genes, their cystic fibrosis may be more or less severe.
Most research estimates that over ten million people in America carry the genetic defects that are cystic fibrosis causes. Most that carry these genes have no idea that they have them and could pass them onto their children.
How Hereditary Genes Become Cystic Fibrosis Causes
The reason why many people can carry the genetic defects without knowing is that cystic fibrosis is caused by defects in a recessive gene. This means that the gene requires two copies, one from each parent, in order for it to be expressed in your body and lead to cystic fibrosis. Most people who are carrying a genetic defect in their CFTR genes have one defective gene and one healthy gene, so they see no effects in their own body’s functioning.
When a person has one defective CFTR gene, they have a 50% chance of passing that gene onto their children. In most cases, this is not a dangerous situation, because their child will likely receive a healthy gene from the other parent. In fact, even if a parent has cystic fibrosis, the risk of their children developing the disease is still low because a healthy gene from the other parent will prevent the disease.
There is only danger of passing on cystic fibrosis if both parents have a defective CFTR gene. If both parents have one defective gene and one healthy gene, there is a 25% chance that one of their children will develop cystic fibrosis. There is also a 25% chance that a child will have no defective genes, and a 50% chance that a child will have one defective gene. If one of the parents has cystic fibrosis and the other has a defective CFTR gene, then the risk becomes even greater, and there is a 50% chance that their child will develop the disease.
Once scientists determined that cystic fibrosis causes were hereditary, it became much easier to prevent the disease. Parents who have a history of cystic fibrosis in their family can check to see if they carry a defective CFTR gene, and they can then determine the probability of them passing it onto their children.