Cystic Fibrosis Genetics

Cystic fibrosis (CF) is a chronic disease of the exocrine glands that currently affects nearly 30,000 Americans. It is a progressive and debilitative disease, meaning that it tends to worsen over time and inhibits one’s ability to function normally.

Due to advances in the treatment of CF, cystic fibrosis life expectancy has gradually increased over the last 50 years. Today, life expectancy for those with cystic fibrosis is approximately 38 years.

While no cure for cystic fibrosis has yet been found, researchers are making great strides toward prevention and treatment of the disease. Studies have proven that cystic fibrosis is an inherited condition, and can be passed on if both parents are carriers of a specific mutated gene. A DNA test can uncover an individual’s genetic predisposition to cystic fibrosis.

Cystic Fibrosis Symptoms

CF symptoms vary in type and severity depending on a variety of factors. Cystic fibrosis symptoms may include:

  • constipation
  • coughing or wheezing
  • delayed growth in children and young adults
  • frequent sinus problems, including bronchitis
  • weight loss.

In infants, symptoms include:

  • delayed growth
  • frequent respiratory infections
  • irregular stools.

Genetic Predisposition to Cystic Fibrosis

Cystic fibrosis is an inherited disease; it is not caused by environmental factors, nor is it contagious. Therefore, a child can have cystic fibrosis only if he inherits the combination of mutated genes that causes the disease.

Cystic fibrosis is passed down to children when both parents carry a mutated CTFR gene. A combination of genes is passed on to a child, who may then develop cystic fibrosis.

Genetic Testing and Cystic Fibrosis

Since certain genes have been isolated as indicators of CF, it is now possible to undergo genetic testing to determine whether you are a carrier of a mutated gene. A genetic test can use your saliva, a hair or a blood sample to determine your genetic makeup. The test is easy and painless.

If you are pregnant, you and your partner can take a cystic fibrosis carrier test. This test gathers DNA from both of you to determine whether your baby may be at risk for cystic fibrosis. You may also take the carrier test if you are considering having a baby in the future.

You may carry the CF gene even if you have no known family history of the disease. Researchers estimate that one in 31 Americans is an unknown carrier of the CF gene.

If both parents are found to be carriers of a mutated CFTR gene, their child will not necessarily be born with cystic fibrosis. Two carrier parents have a 25 percent chance that their child will be affected, a 50 percent chance that the child will be a carrier of the disease and a 25 percent chance that the child will not inherit the mutation at all.

Treatment of Cystic Fibrosis

While no known cure exists for cystic fibrosis, in recent years scientists have made great advances on the treatment of the disease. Certain steps can help to treat the symptoms of the disease, which can greatly ease the discomfort of a person with cystic fibrosis.

Treatments for CF include:

  • aerosol medications to assist lung function
  • antibiotics for infections
  • medical devices to assist breathing
  • percussive physical therapy
  • ventilators for breathing support.

Treatments can be highly individualized for patients based on the type and severity of their symptoms. For people suffering from cystic fibrosis, proper treatment can greatly improve quality of life.


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