Cystic
Fibrosis
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characterized by the buildup of thick, sticky mucus that can damage many of the body's organs
Genetic Causes
Mutations in the CFTR gene
Cystic Fibrosis (CF) is an inherited genetic disorder caused by a mutation in the CFTR (cystic fibrosis transmembrane conductance regulator) gene.
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This gene provides the instructions to make a protein that acts as a channel on the membrane of cells that produce mucus, saliva, tears, sweat, and digestive enzymes.
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This channel can control the movement of water and salt in and out of cells. In patients with CF, the balance of salt and water is disturbed, which causes the aforementioned bodily fluids to become thick and sticky.
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People with only one copy of the defective gene are called carriers. They do not have the condition or its symptoms. To have the disease, both parents must be carriers.
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Symptoms
Diagnosis
CF can be diagnosed using several different methods which include the following:
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DNA test (to look for mutations in the CFTR gene)
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Sweat test (CF patients have higher concentrations of salt in their sweat)
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IRT blood test (high levels of immunoreactive trypsinogen (IRT) in the blood may be a sign of CF)
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Chest X-rays or CT Scans (to identify damage that CF may have caused in the respiratory passageways, liver, or pancreas)
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There are more than 1800 known mutations of the CFTR gene. Because there are so many, most genetic tests only screen for the most common mutations.
Once mucus and other bodily fluids become thick and sticky, they can build up and block tubes and pathways throughout the body. For example, mucus can build up in inside airways in the lung, making it harder to breathe. The built-up mucus can also trap germs and bacteria leading to infections.
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Some common CF symptoms include:
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Wheezing or trouble breathing
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Persistent coughs with thick mucus
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Inflamed nasal passages and sinusitis
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Lung infection
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Digestive problems (Greasy stools, constipation, nausea, …)
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It can also cause severe lung damage like cysts (fluid-filled sacs) and fibrosis (scar tissue). That’s how CF got its name.
Treatment & Management
Unfortunately, there is no absolute cure for CF patients and current treatment methods are used to relieve symptoms. The effectiveness of such treatments depends on the stage of the disease. Some of these treatments include the following:
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Pancreatic enzyme substitution with meals
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Antibiotics to control bacterial infections
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Bronchodilators to keep airways open
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Mucus-thinning drugs
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Fat-soluble vitamin supplements
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Airway clearance or chest physical therapy (CPT) to reduce chest infection and improve lung function
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Regular physical activity to increase pulmonary function and remedy muscle imbalances
Latest Scientific Advancements
Gene replacement or transfer is a technique used to insert the correct copy of the CFTR gene to give cells the ability to make normal CFTR proteins.
Although this technique can't remedy the problems which have occurred before the treatment, it can reduce future symptoms and prevent further damages. However, gene therapies for treating cystic fibrosis are still in their early stages of development.
CFTR Modulators:
Trikafta
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CFTR modulators are drugs that directly target malfunctioning proteins caused by mutated CFTR genes.
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In 2019, the U.S food and drug administration (FDA) approved the first triple-combination CFTR modulating therapy known as Trikafta.
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The drug effectively targets defective proteins made based on the mutated CFTR gene.
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Trikafta can treat CF patients with the most common type of CF mutation that includes 90% of the CF population.
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Trikafta is a significant improvement in CF drug discoveries since it can cover a vast majority of CF patients compared to previous medications.
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It is used for CF patients aged 12 years and older who have at least one F508del mutation in the CFTR gene.
