• Certified clinical diagnostics laboratory

  • Certified clinical diagnostics laboratory

Cystic fibrosis major mutation assay

Testing of most common mutations of the CFTR gene

What is cystic fibrosis?

Cystic fibrosis is a heterogeneous disease caused by mutations in the CFTR gene. This gene describes more than 1,800 different mutations that cause various clinical symptoms. The most common of these mutations is the so-called delta F508 (DF508, rs113993960,NM_000492.3(CFTR):c.1521_1523delCTT (p.Phe508delPhe).

Classic cystic fibrosis usually develops when genome has at least two pathogenic mutations in different chromosomes, or one homozygote mutation. Approximately 70 % of cystic fibrosis patients are delta F508 homozygous. Classic cystic fibrosis can manifest itself as a chronic bacterial infection of the lungs and sinuses, exocrine pancreatic insufficiency, hepatobiliary disorder, lack of vas deferens in males (obstructive azoospermia), increased chloride levels in sweat. If genotype contains one pathogen and one less pathogenic mutation, or a less pathogenic mutation in a homozygous state, clinical symptomatology may not be so severe, the disease may affect one or several organs.

Incidence: 1:2,500, carriers – 1:75

Type of heredity: autosomal recessive

Purpose of the testing: To determine the presence of the most common CFTR gene mutation (DF508) in the genome of patients with clinically suspected cystic fibrosis or CFTR-related pathology; or testing may be carried out to confirm the status of a carrier.

Interpretation of test results:

  • Delta F508 homozygous: the diagnosis of cystic fibrosis is confirmed.
  • Delta F508 heterozygous: carrying of the mutation is confirmed. If patient has a corresponding clinical picture, a full test of the CFTR gene is recommended to determine the heterozygosity of the compound.
  • Delta F508 mutation has not been found – the diagnosis of cystic fibrosis or the carrying of a mutation has not been confirmed. If patient has a corresponding clinical picture, a full test of the CFTR gene is recommended to find other possible pathogenic mutations.

Recommendations in case of a positive result

In cases where the tested mutation has been confirmed, we recommend a consultation by a doctor – a pulmonologist, a gastroenterologist, or a urologist, depending on the clinical symptomatology. A family counselling by a genetic is also recommended to determine the risks of the disease to family members and, if necessary, to determine the status of a carrier of the mutation.

Mutation test method: DNA isolation, PCR, Sanger sequencing of the CFTR gene region containing the mutation.


  • This test determines only delta F508 (D F508) mutation and does not exclude the presence of other pathogen mutations in the tested genome.
  • In rare cases, false negative results may occur due to the possibility of mutations in the site of attachment of oligonucleotides (PCR primers).

To apply for a laboratory visit and give a sample for a test, please:

  • call: + 371 67425241: +371 26267833
  • send the following information to info@genera.lv: the test to be performed, given name and surname, year of birth of the person to be tested, preferred date and time of GenEra laboratory visit, and your phone number.