People with Cystic Fibrosis (CF) have two copies of a gene variant, CFTR, one inherited from each parent. Approximately 1 in 19 people of Irish descent are said to ‘carry’ one copy of the gene that causes CF. However, these people do not have CF.

If both parents 'carry' the gene variant, their child has: 

• 25% chance of being born with CF 

• 50% chance of being a healthy carrier of CF, but not having the condition 

• 25% chance of not having CF and not being a carrier of the altered gene 

If a couple has a family history of CF, it’s a good idea to get genetic carrier screening before starting a family. There are several reasons for this:

• CF is inherited in an 'autosomal recessive manner'. This means that CF may be inherited when both parents carry the CF gene. If both are carriers, there’s a 1 in 4 chance that their child could be born with CF.

• It helps you understand your 'carrier status'. A person could carry the CF gene without having symptoms and testing shows whether you or your partner are carriers. If one partner is a carrier and the other is not, the chance of having a child with CF is low. Knowing your carrier status helps you plan ahead.

• Testing supports informed choices. If both partners are carriers, you can explore options such as:

  • Prenatal testing (e.g., chorionic villus sampling or amniocentesis) to test the baby for CF during pregnancy. 
  • IVF with genetic testing (called PGD) to select embryos without the CF gene.

• Testing allows for early care. Early diagnosis and intervention can help manage symptoms and improve quality of life. If a child is born with CF, understanding the genetic background can also help parents and healthcare providers plan for the child's care from early on.

Your GP can arrange the test for you. They will take a blood sample, complete the paperwork, and send it to the Department of Clinical Genetics for analysis. The results will be sent back to your GP. However, the wait time for results does vary and can take some months.

Testing is done at the Molecular Genetics Laboratory in the Department of Clinical Genetics, CHI Crumlin, Dublin 12.

If CF runs in a family, adults aged 16 and over can have this test. You can also be tested if a partner or a family member is known to carry the CF gene.

Department of Clinical Genetics, CHI Crumlin - Crumlin Hospital 
Tel: 01 409 6739  Email: Clinical.genetics@olchc.ie 

Private genetic testing for Cystic Fibrosis (CF) is available through several clinics, including Genetics.ie and Beacon Care Fertility.  

Genetics.ie: www.genetics.ie 

Beacon Care Fertility:  www.beaconcarefertility.ie