Cystic fibrosis 38 Mutation Sequencing

Cystic fibrosis is caused by mutations in a gene on chromosome 7. This gene encodes the transmembrane conductance regulatory protein (CFTR) of cystic fibrosis. CFTR functions as a chlorine channel at the apical pole of the epithelial cell membrane, participates in the regulation of sodium channels, in the transport of HCO3¯, and so on.

CFTR gene mutations can be grouped into 6 different classes based on their functional effects at the cellular level:

I class: CFTR is not synthesized;

Class II: CFTR is insufficiently processed in the cell;

Class III: CFTR does not work;

Class IV: CFTR has abnormal bandwidth;

Class V: CFTR has a partial defect in the synthesis process;

VI class: CFTR disintegrates rapidly.

Class I, II, and III mutations are more common and are associated with pancreatic insufficiency, while class IV, V, and VI mutations are more rare and in this case patients do not present with pancreatic manifestations.

The result of genetic disorders is the absence or improper functioning of chlorine channels at the cellular level, leading to altered chlorine transport in the mucous and serous glands of most organs. The resulting secretions by the glands are characterized by low water content and viscosity. They attach to the ductal epithelium and are difficult to expel. Accumulation of secretions in the body leads to dysfunction and destruction of various organs (lungs, pancreas, liver, intestines, reproductive organs).

Cystic fibrosis manifests itself in several forms, in some cases it causes premature death of children due to progressive obstructive lung disease with bronchiectasis; Sometimes the disease manifests itself in the form of pancreatic insufficiency and progressive obstructive pulmonary disease in adolescence, with an increased frequency of hospitalization in adulthood. It can also manifest itself in the form of recurrent sinusitis and bronchitis or infertility in young people.

Signs and symptoms of cystic fibrosis vary according to the severity of the disease. Even in the same person the symptoms may worsen or improve over time. Some people may not show symptoms until adolescence or adulthood. People who are not diagnosed with the disease before adulthood usually have a milder disease and are more likely to have atypical symptoms, recurrent attacks of pancreatitis, infertility, and recurrent pneumonia.

The salt content of sweat in patients with cystic fibrosis is higher than usual. Parents can often even feel the taste of salt when kissing their children. Most of the other signs and symptoms of CF are related to the respiratory and digestive systems.

Respiratory signs and symptoms

Thick and sticky mucus associated with cystic fibrosis blocks the bronchi, which can cause signs and symptoms such as:

• Persistent, productive cough with thick sputum;
• wheezing
• Intolerance to physical activity;
• Recurrent lung infections;
• Inflammation of the nasal cavity or a stuffy nose;
• Recurrent sinusitis;

Signs and symptoms related to the digestive system

Thick mucus can also block the ducts that carry digestive enzymes from the pancreas to the small intestine. Without these digestive enzymes, the intestines will not be able to fully absorb the nutrients in the food, which often results in:

• Unpleasant-smelling, greasy stools;
• Problem of weight gain and growth;
• Intestinal blockage, especially in newborns;
• Chronic or severe constipation, which, due to constant tension during defecation, can cause a part of the rectum to fall out of the anus - rectal prolapse.

Cystic fibrosis requires consistent, regular supervision by a physician at least once every three months.

If you or your partner have close relatives with cystic fibrosis, you may have a genetic test before the baby is born. The test can help you determine the risk of having a baby with CF.

Before you decide to get tested, consult a geneticist.

How to prepare for the test?

No special preparation is required for the test.