Cystic Fibrosis - F508del

This test looks for F508del, the single most common genetic variant that causes cystic fibrosis. Cystic fibrosis is an inherited condition affecting the lungs, digestive system, and other organs, caused by variants in a gene called CFTR. The F508del variant accounts for the majority of cystic fibrosis cases, which makes it the key variant to test for. This test uses a reliable, targeted method (ARMS PCR) to detect whether the F508del variant is present.

What it can help assess

• Carrier status: identifying whether you carry one copy of the F508del variant, which is important for family planning
• Supporting a diagnosis: helping to confirm or investigate cystic fibrosis alongside other tests
• Understanding family risk: particularly relevant if you have a family history of cystic fibrosis or a known carrier in the family

Understanding the results

Cystic fibrosis is a recessive condition, which means a person needs to inherit two faulty copies of the CFTR gene, one from each parent, to have the condition. This test can identify:

• No copies of F508del: the variant was not detected
• One copy (carrier): you carry the variant but do not have cystic fibrosis from it. If your partner is also a carrier, there is a chance of passing the condition to a child
• Two copies: consistent with a diagnosis of cystic fibrosis, which would need clinical confirmation

An important note on interpretation

This test looks specifically for the F508del variant and does not detect the many other, rarer variants that can also cause cystic fibrosis. This means a negative result greatly reduces, but does not completely rule out, the chance of being a carrier or being affected. Because this is a genetic test with implications for you and your relatives, any positive or significant result should be discussed with your GP or a genetic counsellor, who can explain what it means and advise on further testing.

Why it matters

Knowing your F508del status can provide valuable information for family planning and for understanding inherited risk, especially where there is a family history. Genetic results are lifelong and can affect other family members, so professional interpretation and, where appropriate, genetic counselling are recommended for anyone with a positive result.