Cystic fibrosis (CF) is an inherited disease in which your body secretions are thick and sticky, which causes damage to the respiratory and digestive systems and other organs.
Your body secretes mucous and fluids that act as lubricants for various body systems. But, in cystic fibrosis, these secretions are thick and sticky. Thus, instead of their lubricant action, they may block the tubes and passways, which cause a wide range of symptoms that may involve the whole body.
Cystic fibrosis affects about 30,000 Americans and more than 70,000 worldwide. About 1000 new cases appear each year. It is more common in the north European ancestry, and it’s the most common life-limiting autosomal recessive disease among them. It is a genetic disease; thus, its population is usually under 18 years old. 75% of the new diagnoses occur before the age of two years old.
Cystic fibrosis is a genetic autosomal recessive disease, which means any child should inherit two copies of the mutated gene from both parents to have this disease. We will discuss this responsible gene later.
Most of our body organs and systems contain mucous secretions; thus, thick and sticky mucous can cause symptoms in the whole body wherever it is mucous. This mucous affects the lungs and the respiratory tubes, which causes breathing difficulties and lung infections and may end in respiratory failure. It also may affect the digestive system and blocks the pancreatic ducts that deliver the digestive enzyme to the intestine. Your body can’t absorb your food without these enzymes.
Cystic fibrosis also affects organs, such as the male reproductive system, kidneys, hearing, and other organs. Patients with this disease may experience other conditions, such as diabetes, osteoporosis, and liver problems.
Diagnosis of cystic fibrosis occurs during the newborn screening as a part of the heel-prick test that takes a blood spot from the newborn for analysis. Positive results -that suggest cystic fibrosis- require further tests to confirm it. These tests include sweat and genetic tests that we will discuss later in detail. We can also use these tests to diagnose older children who didn’t have screening. Diagnosis should also include looking for symptoms and complications to consider in the management.
Cystic fibrosis is a progressive disease, but due to the early screening programs, the early management makes the patients able to live a better and longer life than before. There is no curative treatment for cystic fibrosis, but treatment can alleviate the symptoms, slow the progression, and improves the quality of life. We have multiple treatment options that aim to improve lung functions, nutrition, and overall health. Cystic fibrosis is a complex disease, and its management is the same. Close monitoring and regular follow-up are essential to get the best results.
Now, let’s discuss this complex disease in detail. Let’s answer the following questions:
- What causes cystic fibrosis, and who is at risk?
- What are its symptoms and complications that affect the patient’s life?
- How can the doctors diagnose it?
- What are the available treatment options? And, how can the doctor use them to improve the patients’ life?
Causes and risk factors of cystic fibrosis
Cystic fibrosis is an inherited genetic disease. It occurs due to mutated (or abnormal) CFTR (cystic fibrosis transmembrane conductance regulator) gene. CFTR gene is responsible for making a protein that controls the movement of salt and water in and out of the cells of the lungs, pancreas, and other organs. Mutation in this gene decreases the water outside the cells, which results in thick and sticky mucous that causes the disease symptoms. This mutation also causes salty sweat, which represents a diagnostic value in cystic fibrosis.
Cystic fibrosis is a genetic disease, which means that it runs in families. Thus, positive family history is a risk factor for it.
How does the diseased child inherit this disease?
Cystic fibrosis is an autosomal recessive disease, which means that the diseased child should get two copies of the mutated gene (one from each parent). One copy means that the child is a carrier; he doesn’t have the disease, but he can pass it to his children.
If both parents are carriers:
- Their child will have a 50% chance to inherit a mutated copy and be a carrier.
- Their child will have a 25% chance to inherit two mutated copies and have the disease.
- Their child will have a 25% chance to inherit two healthy copies, which means he won’t be a case or carrier.
If one parent has cystic fibrosis, and the other is a carrier:
- Their child will have a 50% chance to have the disease and to be a carrier.