Cystic Fibrosis (CF)

Symptoms: Persistent cough, wheezing, nasal inflammation, frequent or severe constipation, recurrent lung infections, impaired growth in children, inability to gain weight, dehydration, easily fatigued, male infertility, chronic sinusitis, intestinal blockage.

Causes: Genetic mutation of the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene

Risk Factors: Family history of cystic fibrosis

Prevalence: The disease affects approximately one in every 2,500 to 3,500 white newborns. Cystic fibrosis is less common in other ethnic groups.

Severity: Moderate to severe

Which doctor to consult: Pulmonologists, gastroenterologists, physiotherapists, and nutritionists, depending on the manifested symptoms.

Overview

Cystic fibrosis (CF) is a progressive genetic disorder caused by a mutation of the CTFR (Cystic Fibrosis Transmembrane Conductance Regulator) gene. This mutation causes the cells to secrete excessive mucous, severely damaging the pancreas, lungs, digestive system, and other organs.

CF affects each individual differently. For instance, the mucous can sometimes clog the airways, leading to the build-up of germs and bacteria. Subsequently, this can cause lung inflammation, infections or respiratory failure.
Pancreatic complications in people with CF are related to digestive enzymes. The condition inhibits the absorption of critical nutrients, leading to malnutrition or impaired growth in children.

Concurrently, excessive mucous production often blocks the bile ducts, resulting in various liver diseases or disorders. In addition, male patients can develop issues related to fertility.

Currently, there is no cure for CF. However, medical advancements have made managing the condition much easier and improved the survival rate in affected individuals. Some common medications include antibiotics to prevent infections. Regardless, daily care is still mandatory, with patients having to be especially mindful about avoiding germs.

Types of CF:

Doctors classify cystic fibrosis transmembrane conductance regulator (CFTR) genes into five categories. Cystic fibrosis is caused when a person inherits one copy of a mutated gene from each biological parent. CFTR mutations are recessive, meaning that cystic fibrosis can only be caused by inheriting two gene copies. People who inherit one mutation from a biological parent become carriers, meaning they can pass on the gene and the condition to their children. Those who inherit two mutations develop cystic fibrosis. The type of mutation a person carries can affect the severity of the condition and the treatment options available.

Researchers categorize cystic fibrosis mutations into five groups.

Class 1: Protein Production Mutations:
Protein production mutations occur when the amino acids that makeup proteins are arranged in a way that does not correctly code for the CFTR protein. Typically, there is a code that stops protein production at the appropriate time. A nonsense protein mutation causes production to stop prematurely.
Another protein production mutation, known as a splice mutation, contains irrelevant code that prevents the cell from correctly reading the protein's genetic code.

Class 2: Protein processing mutations:
The CFTR protein typically takes on a specific three-dimensional shape that instructs the cell on correctly using it. Mutations in protein processing result in incorrect amino acid additions or deletions. This modifies the shape of the CFTR protein. This mutation prevents CTFR from moving to the appropriate location within the cell.

Class 3: Gating mutations:
The CFTR protein acts as a gate that allows chloride to pass through. The gate is otherwise closed. Gating mutations prevent the gate from fully opening, reducing or eliminating chloride's ability to enter the cell.

Class 4: Conduction Mutations:
Some mutations that alter one or more amino acids in the CFTR protein allow it to assume the proper shape. However, they impair the protein's function. This may slow protein transport through the protein channel and into the cell. This is a conduction mutation.

Class 5: insufficient protein mutations:
Insufficient protein mutations indicate that there is not enough CFTR protein in each cell. This can happen when the body does not produce enough CFTR when only a portion of the CFTR works, or when the protein on the cell's surface degrades too quickly. This impairs the function of the chloride channel.

Symptoms of CF:

 Symptoms of CF can vary but typically involve the respiratory and digestive systems. Here are some common symptoms:

Respiratory symptoms:

Persistent cough with phlegm
Wheezing and shortness of breath
Repeated lung infections
Inflamed nasal passages or a stuffy nose
Recurrent sinusitis

Digestive symptoms:

Difficulty gaining weight and poor growth despite a good appetite
Foul-smelling, bulky, greasy stools
Intestinal blockages, particularly in newborns
Diarrhea or constipation

Other symptoms may include salty-tasting skin and male infertility. It’s important to note that these symptoms can vary widely among individuals with CF and can change over time. If you suspect CF or have concerns about these symptoms, it’s crucial to consult a healthcare professional for proper diagnosis and management.

Causes of CF:

Cystic fibrosis is an inherited condition caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This gene provides instructions for making a protein that regulates the movement of salt and fluids in and out of cells. When the CFTR gene is mutated, it produces a protein that doesn’t function properly.

The defective CFTR protein affects the salt and water balance on cell surfaces, resulting in the thick and sticky mucus characteristic of cystic fibrosis. This abnormal mucus can clog the airways and ducts in the body, leading to the various symptoms and complications associated with the disease.

To have cystic fibrosis, an individual must inherit two copies of the mutated CFTR gene, one from each parent. If both parents are carriers of the mutation, their children have a 25% chance of having cystic fibrosis, a 50% chance of being carriers, and a 25% chance of not having the mutation at all. Carriers usually do not show disease symptoms but can pass the mutated gene to their offspring.

Risk factors:

The risk factors for CF are primarily genetic. Here are the key points:

Genetic Inheritance: CF is an autosomal recessive disorder, meaning a person must inherit two copies of the mutated CFTR gene, one from each parent, to have the disease.
Carrier Parents: If both parents are carriers of the CFTR gene mutation, there is a 25% chance their child will have CF, a 50% chance the child will be a carrier and a 25% chance the child will not inherit the mutation.
Ethnicity: Certain ethnic groups have higher carrier rates for CF. For example, it is more common among Caucasians and people of Northern European descent.
Family History: Having a family member with CF increases the likelihood of being a carrier or having the disease. It’s important to note that being a carrier of the CFTR mutation does not mean an individual will develop CF, but they can pass it on to their children. Genetic testing can identify carrier status and help assess the risk of having a child with CF.

Possible Complications:

Chronic Bacterial Infections: The mucous in the affected organs often leads to bacterial build-up. This can further cause infections like sinusitis, pneumonia or bronchitis. In a few cases, the microorganisms may also resist conventional antibiotic medication.

Pneumothorax (collapsing of the lungs): CF may sometimes cause air to seep into the space between the chest wall and the lungs, directly causing the organ to wholly or partially collapse. Individuals suffering from such a condition report experiencing immense chest pain, breathlessness, or a bubbling sensation in the region.

Issues Surrounding Fertility: In male patients, CF almost always leads to infertility because the condition blocks the tubes connecting the prostate gland and the testes. In females, the disorder may make conceiving difficult for females but not entirely lead to infertility. However, pregnancy can worsen the effects of CF.

Diabetes: Due to CF inhibiting pancreatic functions, affected individuals may suffer from reduced insulin production. Subsequently, patients have an increased risk of developing diabetes.

Liver Disease: The connecting tube between the liver and the gallbladder often gets clogged or inflamed due to excessive mucous. Consequently, this results in several hepatobiliary problems, including jaundice, cirrhosis or fatty liver disease.

Intestinal Obstruction: CF typically results in several issues related to the intestines. Structural blockages, intussusception (partial displacement of the intestines) and Distal Intestinal Obstruction Syndrome (DIOS) are all common occurrences due to the condition.

Bronchiectasis (damaged airways): Most CF patients may develop bronchiectasis, which involves scarring and abnormal widening of the air tubes. This makes it difficult for the lungs to transport oxygen. In addition, bronchiectasis usually occurs close to the blood vessels, which can cause them to rupture. In such cases, patients will often experience haemoptysis (coughing blood).

Nutritional Deficiencies: The inhibition of digestive enzyme release can result in patients suffering from malnutrition. More severe instances may stop the body from absorbing fats, vitamins and proteins. Such complications can cause impaired development in children and pancreatic inflammation in adults.
Respiratory Failure. Since CF is a progressive disorder that damages the lung tissues, patients will gradually experience deteriorating lung functioning. Over time, this will cause the lungs to stop working entirely, leading to respiratory failure.

Prevention:

CF is a genetic condition; as such, it cannot be prevented if the necessary mutations are present in an individual’s genes. However, some measures can help reduce the risk of having a child with CF:

Genetic Counseling: Couples with a family history of CF or who are known carriers of the CFTR gene mutation can benefit from genetic counselling to understand their risks.
Carrier Testing: Genetic testing can identify carriers of the CFTR gene mutation, informing family planning decisions.
Prenatal Testing: For pregnant women at risk of having a child with CF, prenatal tests can determine if the fetus has CF.
IVF with Preimplantation Genetic Diagnosis (PGD): This technique allows couples at risk of passing on CF to have embryos tested for the CFTR mutation before implantation during in vitro fertilization.
If you are considering these options, it’s important to consult healthcare professionals for personalized advice and support. While CF itself cannot be prevented after conception, these measures can help manage the risk and prepare for the potential needs of a child with CF.

When to Consult a Doctor?

On Manifestation of Symptoms: In most cases, symptoms for CF begin to appear at the age of two. However, some children do not demonstrate signs until they are in their early or late teens. Nonetheless, poor growth in children, frequent respiratory problems, persistent coughing, and excessive mucous could be due to CF. As such, it is critical to consult a pulmonologist when symptoms appear.

Family History of CF: Due to the disorder being genetic, CF only manifests in children who have two mutated variants of the CFTR gene. Thus, children with a family history of the condition need to be consulted with an expert to verify the existence of the same. Conversely, anyone with just one gene variation may be a carrier and pass it on to their children.

Antenatal Screening: For couples trying to conceive, it is vital to opt for a screening in case both are carriers. In such cases, the parents themselves will not exhibit any symptoms or be generally affected by the condition, making it challenging to recognise. However, the child may develop the disorder and suffer from related complications.

Diagnosis:

General Examination: Clinical diagnosis of CF is usually possible when the symptoms appear in at least one of the typical organs (lungs, liver, pancreas, digestive system, intestines). In other cases, a sweat chloride test can identify the existence of a CTFR gene mutation. Because CF patients produce high levels of salt in their sweat, any abnormal results can help diagnose the disorder.

Advanced Diagnostic Tests:

• Immunoreactive Trypsinogen (IRT) Test: Standard infant screening involves an IRT test. This clinical assessment examines IRT protein levels in the blood. Any elevation or deviation in this context can indicate CF. However, doctors usually prescribe additional medical examinations to confirm the presence of the disorder.

• Pulmonary Function Test (PFT): PFT assesses the functioning of the lungs to determine any related complications. Such clinical examinations accurately measure the quantity of air an individual can inhale or exhale. In addition, the test focuses on whether the lungs can adequately transport oxygen to other organs. Abnormalities in both areas can be an indicator of CF.

• Computerized Tomography (CT) Scan: Pulmonologists and other medical experts use a CT scan to study detailed internal body images. Subsequently, these scans enable doctors to look for organ damage or excessive mucous secretion signs. The existence of the same can be used to provide a diagnosis for CF.

Treatment: 

Home Care: In most patients, CF can cause intestinal blockage or inhibit the release of digestive enzymes. As such, diagnosed individuals may need to increase their caloric intake and adopt a fibre-rich diet.
In addition, regular exercise, including brisk walks, biking or swimming, can mitigate the effects of mucous in the airways. Medical experts also recommend supplements such as multivitamins, pancreatic enzyme capsules and antacids.

Medication: The treatment for cystic fibrosis (CF) includes various medications to manage symptoms and reduce complications. Here are some examples:

• Antibiotics: Used to improve lung function by impeding the growth of bacteria. Examples include Tobramycin, Colistin, and Aztreonam.

• Anti-inflammatory drugs, such as Ibuprofen, are used to prevent inflammation in the airway passages.

• Mucus thinners: Like Acetylcysteine, to help patients cough up mucus and improve lung function.

• Bronchodilators: Medications like Albuterol (Salbutamol) and Salmeterol open up and relax muscles around the bronchia (lungs).

• CFTR modulators, such as Ivacaftor, target specific defects in the CFTR protein so that it can work properly.

• Pancreatic enzymes: Including Lipase and Trypsin to aid in the absorption of nutrients in the digestive tract.
  These medications are often combined with other treatments, such as chest physiotherapy, oxygen therapy, and dietary adjustments, to manage the disease effectively. Working with a healthcare team to find the best treatment plan for an individual with CF is important.

Surgical Treatment: While there is no surgical cure for CF, specific procedures can help alleviate the complications caused by the condition. These include sectional bowel surgery to remove a blocked region in the intestines or inserting feeding tubes to aid in nutrient absorption.

In the most severe case, a lung transplant may be the only option to extend the patient's life. Regardless, the procedure will not eliminate the mutated CTFR gene and requires the patients to manage their symptoms post-operation.

Alternative Management: Regular visits to a physiotherapist for chest therapy can help loosen the accumulated mucous in the lungs. Such techniques must be performed at least 1 to 2 times a day.
Mechanical devices like a chest clapper or an inflatable vibrating vest can also be used instead of chest therapy.

Additional Information

Risk of Developing CF Due To Family History & Ethnicity:

Individuals with one mutated CTFR variant will only be carriers of the disorder. However, they can pass on the gene to their child. Subsequently, if the affected person has additional children, there is a 1/4th chance that each child may have CF or be a carrier.

This can lead to the condition being dormant across generations. So, a clinical diagnosis of the disease may be surprising to those without a recent family history of the disorder.

Nonetheless, the Cystic Fibrosis Foundation has established that specific ethnicities are more likely to develop the condition. Caucasian and Hispanic people are the two primary at-risk groups in this regard, followed closely by African and Asian natives.