Cystic Fibrosis Carrier Screening

What is cystic fibrosis?

Cystic fibrosis (CF) is an inherited disease athat severely affects breathing and digestion by the accumulation of thick mucus. It is this mucus that promotes life-threatening infections. There is no cure for CF, but advances in supportive treatment are able improve quality of life and increase the average life expectancy to 30 years of age for individuals with CF.

Carrier testing for CF

A blood test can see if parents-to-be have the abnormal gene that causes CF. The test can help determine if you are at an increased risk for having children with CF.

A carrier is a healthy individual who has 1 working and 1 non-working copy in the gene associated with CF disease. It is when an individual inherits 2 non-working copies of the CF gene that they are affected. Being a carrier for CF does not cause health problems. In fact, it is estimated that in the general Caucasian population the carrier frequency is between 1/25 to 1/29.

Anyone could be a carrier. However, the chance of being a carrier for CF is dependent on your race/ethnicity.

Cystic fibrosis carrier screening detects the more common mutations in the CF gene. Within the Caucasian population, the detection rate is known to be between 80-90%. This detection rate changes based on a person’s ethnicity. If your test results do not show a CF gene mutation, the chance that you are a CF carrier is very low.

If your test shows you have 1 CF mutation, then you are a carrier. You may consider having carrier screening for the father of the baby. If one member of the couple is a CF carrier and the other is not, then the risk is less than 1 in 1000 (<0.1%) of having a child affected with CF.

If it is determined that you and your partner are both carriers of a CF mutation, there is a 25% chance during each pregnancy to have a child with CF. It is important to note that even if two parents are carriers of CF there is still a 75% chance for each pregnancy that the child will not be affected.

It is possible to have prenatal diagnosis to determine if the fetus is affected with CF. This could be done either between 10-12 weeks in pregnancy by CVS (chorionic villus sampling) or 15 weeks and later by an amniocentesis. When a carrier couple is identified, a genetic counselor can provide information and support which may be helpful in making important family planning decisions.

Learn more

Genetic Counseling Services translates scientific knowledge into practical information that you can use in making family decisions. For more information about genetic counseling, click here or call 918-293-6200.

For genetic counseling for cancer, click here.

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