Cystic fibrosis is a genetic and hereditary disease that affects 1 in 5,000 newborns. Moreover, it is estimated that 1 out of every 35 people are healthy carriers of the disease. Genetic testing before having offspring is very important to know if the couple is a carrier of the disease or not.
Cystic fibrosis causes an accumulation of thick, sticky mucus mainly in the lungs, but also in the pancreas, liver and intestine. It is caused by a mutation in the CFTR gene, which encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein.
Is cystic fibrosis recessive or dominant?
It is a disease of autosomal recessive inheritance, that is, two copies of the defective CFTR gene (one from the father and the other from the mother) are necessary for the disease to occur. Therefore, if you plan to have offspring, it is important to have a genetic test to find out whether the parents are carriers or not. If both are carriers, assisted reproduction techniques can be used to avoid passing it on to the offspring.
The mutation in the CFTR gene causes the body to produce thick, sticky mucus that accumulates in the airways, clogging the airway bacteria. This buildup causes life-threatening lung infections and serious digestive problems. In addition, the accumulation of mucus in the pancreas prevents the release of digestive enzymes that allow the body to break down food and absorb nutrients.
The symptoms, therefore, affect the respiratory and digestive systems. Characteristic respiratory symptoms are recurrent lung infections, respiratory allergy, fatigue and progressive lung damage. On the other hand, digestive symptoms include increased fat in the stool, salty taste of the skin, abdominal pain and weight loss.
As it is an inherited disease, the risk factor is having a family member who is a carrier or has cystic fibrosis. It is the most frequent lethal recessive hereditary disease in the Caucasian race. Therefore, it is important to perform a genetic test for the detection in those people with a family history, in this way it is possible to detect how many carriers there are in a family.
Prevention, fundamental to fight against the cystic fibrosis genetic inheritance
Although there is no cure for this disease, an early diagnosis can prolong the life expectancy of those affected by cystic fibrosis. The most commonly used tool for diagnosis is the sweat test; a high level of salt in a person’s sweat is a sign of the disease. However, if there are suspicions of being a carrier, it is advisable to have a DNA test to determine the absence or presence of the mutation in the CFTR gene.
Prevention and research are fundamental objectives in understanding how cystic fibrosis develops. Genetic testing that can detect the defective CFTR gene can be a first step in making decisions, mediated by genetic counseling, in people with a family history of cystic fibrosis.