Cystic Fibrosis Causes: What’s the Genetic Connection?

family walking hand in hand

Story at-a-glance -

  • Cystic fibrosis is a genetic disease, meaning that it is caused by a faulty gene that has been passed down from a person’s parents
  • Researchers are still studying the CFTR gene and its mutations to discover the best therapeutic approaches to target thesefects. They aim to discover ways to improve the quality of life and alleviate the symptoms of individuals affects with cystic fibrosis

Cystic fibrosis is a genetic disease, meaning that it is caused by a faulty gene that has been passed down from a person’s parents. Over 10 million Americans today carry this faulty gene, but most of them do not know that they are cystic fibrosis carriers.1 In the U.K., it’s said that 1 in 25 people is a CF carrier.2

What Causes Cystic Fibrosis?

When there is a defect in the gene that controls the movement of salt and water in and out of your body’s cells, cystic fibrosis occurs. This gene, called the “cystic fibrosis transmembrane conductance regulator” gene, or CFTR gene,3 is located on human chromosome 7, and is made up of 250,000 DNA nucleotides.4 The CFTR gene produces a protein that controls the said fluids’ movements.

However, in some people, the CFTR gene has defects, causing it to produce a protein with a faulty structure that does not work well. As a result, these people’s mucus becomes very thick and stickier than normal, and their sweat contains more salt than normal.5

There are actually over 1,700 types of mutations or defects that can occur in the CFTR gene. Some of these are common, while others occur in only a handful of people. These different mutations also have a correlation with the symptoms of cystic fibrosis. For example, some CF mutations are more likely to affect the lungs instead of the GI tract.6

Cystic Fibrosis Genetics: How Is It Passed on?

Keep in mind that genes come in pairs. One set is inherited from your mother, while the other comes from your father. If you inherit a copy of the CFTR gene from both your parents, there’s a large chance that you will have cystic fibrosis. This can happen even if the parents are just CF carriers — meaning, they both do not have cystic fibrosis but they do carry the faulty gene. When they reproduce, their child will most likely have cystic fibrosis. The image below shows the cystic fibrosis inheritance pattern:7

Source: National Heart, Lung and Blood Institute

Basically, this is how the CFTR genes are inherited: If each parent carries a normal CFTR and faulty CFTR gene, there’s a:

25 percent chance for each child to inherit two normal genes

50 percent chance of inheriting a normal gene and one faulty gene (meaning the child becomes a CF carrier)

25 percent chance of inheriting two faulty genes (the child will then have cystic fibrosis)

This is called an autosomal recessive inheritance pattern. Other genetic diseases that can be inherited through this pattern include sickle cell anemia, thalassemia and Tay-Sachs disease.8

Studies on How to Address CF Gene Mutations Are Still Ongoing

Researchers are still studying the CFTR gene and its mutations to discover the best therapeutic approaches to target these defects. They aim to discover ways on how to improve the quality of life and alleviate the symptoms of individuals affected with cystic fibrosis. If you know anyone who is struggling with this condition, the Cystic Fibrosis Foundation offers free genetic testing through their Mutation Analysis Program, so you can determine what mutation you have.9

MORE ABOUT CYSTIC FIBROSIS

Cystic Fibrosis: Introduction

What Is Cystic Fibrosis?

Cystic Fibrosis Symptoms

Cystic Fibrosis Causes

Cystic Fibrosis Treatment

Cystic Fibrosis Prevention

Cystic Fibrosis Diet

Cystic Fibrosis FAQ


< Previous

Cystic Fibrosis Symptoms

Next >

Cystic Fibrosis Treatment

Post your comment