Cystic fibrosis is a serious and incurable hereditary disease caused by mutations in the CFTR gene, which controls the activity of chloride channel in the cell membrane. Cystic fibrosis affects many organs, especially respiratory, digestive and reproductive systems. In the bronchi of the patient thick mucus is formed in which bacteria causing recurrent respiratory infections settle. This leads to permanent lung damage. Most patients suffer from nutritional disorders due to reduced activity of the pancreas, which does not produce digestive enzymes correctly. Therefore, despite high-calorie diet, the patients do not thrive and do not gain weight. Men are infertile since no sperm is present in the semen (azoospermia) due to congenital absence of vas deferens.
How is cystic fibrosis inherited?
CF is an autosomal recessive genetic disease, meaning that development of the disease requires presence of two mutations in the patient - one mutation inherited from the mother, the other from the father. Parents of the patient are therefore healthy carriers of the mutation (predisposition for disease) and have a 25% chance of having a child with cystic fibrosis. One person in 26 is a carrier of the mutation of CFTR gene in the Czech population!
What is the procedure of genetic testing of CF?
The goal of genetic testing is to confirm or exclude mutations of the CFTR gene in the investigated patient. Until today about 1800 of its mutations are known, the most common of which is the F508del mutation. Our implementation of the test detects 50 mutations in the CFTR gene that are commonly found in the European population. Their absence reduces the risk of carrying the mutation of the CFTR gene to 1:400. In case of proven mutations we recommend molecular genetic analysis of close and distant relatives as a prevention of CF in the family.
What is the prevention of cystic fibrosis?
Cystic fibrosis is currently an incurable disease and its effects can be only alleviated with early diagnosis. The only prevention before the birth of such a handicapped child for parents with risk of CF is use of assisted reproductive techniques with preimplantation diagnosis (PGD), in which only genetically healthy embryos are selected for transfer into the uterus. If pregnancy occurs in a natural way, the parents can undergo prenatal diagnosis (genetic testing of the fetus during pregnancy) and terminate the pregnancy due to genetic indications when there is evidence of a disabled fetus.