Molecular testing for cystic fibrosis is done for laboratory confirmation of the disease, during prenatal screening and searching for carriers of the gene mutations, as well as searching for possible carriers in the family environment of patients or carriers of the disease.
Cystic fibrosis (CF) is caused by a mutation in the regulator of the cystic fibrosis transmembrane conductance regulator (CFTR) gene located on chromosome 7. This gene encodes the synthesis of a protein that serves as a channel through which chloride ions enter and leave certain types of epithelial cells. A mutation in this gene alters the ability of the cell to regulate the transport of chloride ions. Carriers of cystic fibrosis mutations in Greece are about 4% of the population and it is the second most frequent (after beta-thalassemia) genetic disease.
So far, more than 1.700 mutations (and new ones are constantly being added) have been discovered that can cause cystic fibrosis. Some tens of these mutations account for 90% of the known mutations in the Caucasian tribe. However, the most common mutation, which accounts for about 50% of cases of cystic fibrosis, is known as ΔF508 and results in the lack of the phenylalanine amino acid at position 508 of the protein sequence.
Cystic fibrosis is an autosomal recessive disease. The carrier has a mutated copy of the CFTR gene while mutations in both copies of the CFTR gene must be present for cystic fibrosis to occur. Genetic screening of the gene is used to identify both cystic fibrosis carriers and neonates and embryos with the disease. The use of molecular tests for cystic fibrosis is often limited to those with a family history of cystic fibrosis. The main purpose of genetic testing is to identify people who could conceive a child with cystic fibrosis.
It is important to clarify that not all patients who have a mutation in the CFTR gene will develop the disease. In addition, because not all mutations that can cause cystic fibrosis can be detected, a negative result does not necessarily eliminate the likelihood of the disease.
- ΔF508 mutation test (~50% of mutations)
- Test of 186 mutations (~89% of mutations)
- Test of 1.700 mutations (~99.6% of mutations)
- Sequencing of the entire CFTR gene (~100% of mutations)
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.