Cystic Fibrosis - CFTR full gene sequencing (NGS)

This test provides a comprehensive analysis of the CFTR gene, the gene responsible for cystic fibrosis, using next-generation sequencing (NGS). Rather than looking for a single variant, full gene sequencing reads through the entire gene to detect a wide range of variants that can cause or contribute to cystic fibrosis. This makes it the most thorough genetic test for the condition.

Cystic fibrosis is an inherited condition affecting the lungs, digestive system, and other organs. It is caused by variants in the CFTR gene, and while one variant (F508del) is by far the most common, there are hundreds of others. By sequencing the whole gene, this test can identify both common and rarer variants that a single-variant test would miss.

What it can help assess

• Carrier status: identifying whether you carry a CFTR variant, which is important for family planning
• Supporting a diagnosis: helping to confirm or investigate cystic fibrosis alongside other tests, including where symptoms are present but common variants have not been found
• Understanding family risk: particularly relevant if you have a family history of cystic fibrosis or a known variant in the family
• Providing a comprehensive result: especially useful for people whose ancestry is associated with rarer variants not covered by targeted tests

Understanding the results

Cystic fibrosis is a recessive condition, meaning 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 variants detected: no CFTR variants were found across the gene
• One variant (carrier): you carry a 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 variants: consistent with a diagnosis of cystic fibrosis, which would need clinical confirmation

An important note on interpretation

Full gene sequencing is highly comprehensive, but no genetic test can guarantee that every possible variant has been detected, and sequencing can sometimes identify variants whose significance is uncertain. Because this is a genetic test with lifelong implications for you and your relatives, results are best interpreted by a specialist. Any variant found, or any uncertain result, should be discussed with your GP or a genetic counsellor, who can explain what it means and advise on next steps.

Why it matters

By reading the entire CFTR gene, this test offers the most complete assessment of your genetic risk of cystic fibrosis, well beyond what a single-variant test can provide. This can be especially valuable for family planning, for investigating unexplained symptoms, and for those whose background may involve rarer variants. Given the family implications, professional interpretation and, where appropriate, genetic counselling are recommended.