cystic fibrosis


Table of Contents


Cystic fibrosis (CF) is a genetically inherited disease and is considered the most prevalent life-threatening recessive genetic chronic condition, primarily affecting the respiratory and digestive systems. It primarily affects the functioning of exocrine glands, resulting in persistent lung infections and inadequate production of pancreatic enzymes.

Without proper treatment, individuals with CF face a range of complications, with lung involvement observed in approximately 90% of those who survive beyond infancy. CF is caused by the inheritance of a defective gene that impacts the cells responsible for producing mucus, sweat, and digestive juices. This genetic defect leads to the accumulation of thick mucus in various organs, including the lungs and pancreas.

In individuals without cystic fibrosis, this mucus is thin and easily cleared. However, in CF patients, the faulty gene results in the production of thick and sticky mucus, which obstructs various channels, tubes, and passages, particularly in the lungs and pancreas. This blockage in the lungs can severely impede normal breathing, leading to substantial mucus buildup and significant breathing difficulties.

Effectively managing this thick mucus necessitates extensive treatments, including the use of mucus-dissolving medications and consistent physiotherapy focusing on lung health. The continuous strain on the lungs can lead to structural damage and frequent infections, which can escalate into pneumonia. CF is a progressive and chronic condition that also affects other organs, including the liver, sinuses, intestines, and reproductive organs.

In vitro fertilization (IVF) and preimplantation genetic testing (PGT) are significant advancements in the realm of reproductive medicine and genetics, particularly for individuals at risk of transmitting genetic disorders like CYSTIC FIBROSIS. For couples with a known risk of passing on CYSTIC FIBROSIS  to their offspring, IVF coupled with PGT offers a proactive approach. In this process, eggs are fertilized in a lab setting, and the resulting embryos are screened for the specific genetic mutations associated with CYSTIC FIBROSIS. This enables the selection of embryos without the disorder for implantation, significantly reducing the likelihood of the child inheriting CYSTIC FIBROSIS. Thus, IVF and PGT provide a powerful combination for family planning, particularly for those with a genetic predisposition to this condition, allowing them to minimize the risk of genetic transmission while achieving pregnancy.

Other name of this disease:

CF, Cystic fibrosis of pancreas, Fibrocystic disease of pancreas and Mucoviscidosis

CF Prevalence and Historical Context:

Cystic fibrosis is most prevalent among individuals of white ethnicity and is the primary genetic disease that can lead to death within this demographic. In the United States, around 40,000 children and adults are affected by CF. The distribution of CF prevalence among different populations is as follows:

– Individuals of Northern European descent: 1 case per 3,200-3,500 in the population

– Hispanics: 1 case per 9,200-9,500 in the population

– African Americans: 1 case per 15,000-17,000 in the population

– Asian Americans: 1 case per 31,000 in the population

Worldwide, the occurrence of CF varies significantly, ranging from 1 case per 377 live births in certain regions of England to 1 case per 90,000 live births among Asians in Hawaii. It is estimated that approximately 1 in every 25 individuals in the UK carries the CF gene. Globally, CF affects 105,000 children and adults across 94 countries.

In Canada, approximately 1 in every 3,000 children born has CF. Australia reports around 3,000 CF patients, with approximately 1 in every 25 Australians carrying the CF gene. Among Black newborns, CF prevalence is approximately 1 in 17,000, while among newborns of Asian descent, it is approximately 1 in 31,000.

Figure 5 Males outnumber females at all ages

Occurrence of CF and Mutation Impact:

CFTR Gene Mutation Effects:

The CFTR gene encodes a protein that plays a vital role as a chloride channel, maintaining the delicate balance of salt and water within cells. When mutations occur in the CFTR gene, this balance is disrupted, leading to significant consequences. These consequences include the thickening of bodily secretions due to dehydration and an increased loss of salt through sweat.

Carrier Status Explanation:

A carrier is an individual who possesses only one mutated copy of a specific gene. In the context of cystic fibrosis, both parents of a child with CF carry one mutated CF gene and one normal gene. These carriers do not exhibit any symptoms of the disease themselves.

Impact of Dysfunctional CFTR:

A dysfunctional CFTR protein leads to reduced chloride secretion and an increase in sodium and water reabsorption across epithelial cells. This alteration results in decreased levels of epithelial lining fluid and less hydrated mucus, making the mucus more susceptible to bacterial adhesion. This, in turn, promotes infection and inflammation. Consequently, secretions in various areas of the body, such as the respiratory tract, pancreas, gastrointestinal tract, sweat glands, and other exocrine tissues, become thicker and more challenging to clear.

Inheritance of Cystic Fibrosis (CF):

Cystic fibrosis (CF) follows a recessive genetic pattern, requiring the presence of two faulty gene variants (formerly referred to as mutations) for the disease to manifest. To develop CF, an individual must inherit one defective gene from each parent. Parents who possess only one copy of the mutated CF gene are considered carriers and do not exhibit symptoms of the condition.

Odds Based on Parental Carrier Status:

When both parents are carriers:

– There is a 25% chance that their child will inherit no defective genes, thus neither having CF nor being a carrier.

– There is a 50% chance that their child will inherit one defective gene, making them a carrier.

– There is another 25% chance that the child will inherit the faulty gene from both parents, resulting in the development of cystic fibrosis.

If one parent has cystic fibrosis, and the other is a carrier:

– There is a 50% chance that their child will become a carrier.

– There is another 50% chance that the child will have cystic fibrosis.

Innate Nature of Cystic Fibrosis:

Cystic fibrosis is a congenital condition, meaning that individuals are born with it. It is not an infectious disease, and therefore, it cannot be transmitted from one person to another. Understanding the genetic basis of CF is vital in comprehending its inheritance patterns and the likelihood of its occurrence in families.

Symptoms of Cystic Fibrosis (CF):

Cystic fibrosis can manifest with a wide range of symptoms, which may vary in severity and progression over time. Some individuals may not exhibit any symptoms until adolescence or adulthood, with adult-onset cases typically presenting milder symptoms such as recurring pancreatitis, infertility, and pneumonia.

Individuals with CF often have saltier sweat than normal, a noticeable characteristic when kissed by their parents. The primary symptoms of CF predominantly affect the respiratory and digestive systems.

Respiratory Symptoms:

The thick mucus associated with CF obstructs the airways, leading to respiratory symptoms like:

– Chronic cough with thick phlegm production

– Breathlessness and wheezing

– Difficulty in performing physical activities

– Frequent lung infections

– Swollen nasal passages

– Persistent sinusitis

– Frequent bacterial and fungal respiratory infections

– Nasal polyps (soft outgrowths in nasal passages)

– Bronchiectasis (damage to bronchial tubes)

– Lung collapse, often triggered by severe coughing episodes

Digestive Symptoms:

The dense mucus also affects the pancreas, hindering the delivery of digestive enzymes to the digestive tract. Consequently, individuals with CF face difficulties in nutrient absorption, leading to symptoms such as:

– Greasy, foul-smelling stools

– Weight gain challenges and stunted growth

– Episodes of diarrhea, constipation, or bulky, odorous feces

– Intestinal blockages, especially in newborns (meconium ileus)

– Persistent or acute constipation, possibly resulting in rectal prolapse

– Abdominal pain

– Increased intestinal gas

Additional Symptoms:

Other symptoms of CF include:

– Frequent chest infections

– Jaundice (yellowing of skin and eyes)

– Newborn intestinal obstruction shortly after birth

– Clubbing of fingers and toes due to inadequate oxygen supply

– Elevated body temperature and night sweats

– Muscle and joint pain

– Hemoptysis (coughing up blood)

– Formation of gallstones

Individuals with CF are also at risk of associated conditions such as diabetes, osteoporosis (fragile bones), male infertility, and liver complications.

Atypical CF:

Less common forms of CF may not be diagnosed until adulthood. Respiratory symptoms in atypical CF can include:

– Chronic sinusitis

– Breathing difficulties, possibly misdiagnosed as asthma or COPD

– Nasal polyps

– Recurrent pneumonia

– Dehydration or heat stroke with abnormal electrolyte levels

– Fertility issues

– Diarrhea

– Pancreatitis

– Unintended weight loss

Symptoms in Infants:

While CF symptoms vary, infants with the condition typically exhibit signs by age two. However, some may remain symptom-free until later. Suspicion of CF may arise if infants show:

– Persistent diarrhea

– Foul-smelling stools

– Oily bowel movements

– Frequent wheezing

– Recurrent pneumonia or other lung problems

– Persistent cough

– Salty-tasting skin

It’s important to note that CF symptoms can resemble those of other medical conditions, making accurate diagnosis crucial for appropriate management.

CF Risk Factors:

Several factors contribute to the risk of developing cystic fibrosis (CF):

  1. Genetic Factors: Cystic fibrosis is a hereditary disorder with a strong familial pattern. Having a family history of CF is a significant risk factor. If one or both biological parents are carriers or affected by CF, the chances of an individual inheriting the condition increase.
  2. Race and Ethnicity: CF predominantly affects individuals of white Northern European descent.

Understanding these risk factors is essential for assessing the likelihood of CF occurrence in individuals and families.

Complications Associated with Cystic Fibrosis (CF):

Complications affecting the Respiratory System:

  1. Damaged Airways (Bronchiectasis): CF contributes to the development of bronchiectasis, a chronic lung condition characterized by abnormal expansion and scarring of the air passages (bronchial tubes).
  2. Chronic Infections: Thick mucus in the respiratory system promotes the growth of bacteria and fungi, leading to frequent sinus infections, bronchitis, and pneumonia.
  3. Nasal Polyps: Inflammation and swelling of the nasal lining can result in the formation of soft, fleshy outgrowths known as nasal polyps.
  4. Coughing up Blood (Hemoptysis): Bronchiectasis near blood vessels in the lungs can cause the expulsion of blood during coughing, though typically in small amounts.
  5. Pneumothorax: Air entering the space between the lungs and the chest wall can lead to partial or complete lung collapse, more common in adult CF patients.
  6. Respiratory Failure: Over time, CF can severely damage lung tissue, causing a decline in lung function that can become life-threatening. Respiratory failure is often the leading cause of death.
  7. Acute Exacerbations: CF patients may experience episodes of worsening respiratory symptoms, requiring antibiotic treatment and sometimes hospitalization.

Complications affecting the Digestive System:

  1. Nutritional Deficiencies: Thick mucus can block the ducts transporting digestive enzymes from the pancreas to the intestines, resulting in poor absorption of nutrients like proteins, fats, and fat-soluble vitamins.
  2. Diabetes: CF elevates the risk of developing diabetes, affecting about 20% of teenagers and 40%-50% of adults with CF.
  3. Liver Disease: Obstruction and inflammation of the bile ducts can cause liver-related problems, including jaundice, fatty liver disease, cirrhosis, and the formation of gallstones.
  4. Intestinal Obstruction: CF patients of all ages may experience intestinal blockages, with intussusception being a possible complication.
  5. Distal Intestinal Obstruction Syndrome (DIOS): A condition characterized by blockage at the junction of the small and large intestines, requiring immediate medical attention.
  6. Digestive Tract Cancers: Increased risk of cancers affecting the esophagus, stomach, small bowel, large bowel, liver, and pancreas.
  7. Pancreatitis: Inflammation of the pancreas can occur and lead to nutritional deficiencies.
  8. Salt Loss Syndrome: Rapid loss of salt, specifically sodium and chloride, can result in electrolyte imbalances and urinary incontinence.
  9. Vitamin Deficiencies: CF patients may experience deficiencies in vitamins A, D, E, and K.
  10. Gastroesophageal Reflux Disease (GERD): Stomach contents can flow back into the esophagus, potentially causing significant harm.

Complications affecting the Reproductive System:

  1. Infertility in Men: Most men with CF have a condition called CBAVD, where the vas deferens, responsible for carrying sperm, are blocked by mucus and do not develop properly, rendering them infertile without fertility treatments.
  2. Reduced Fertility in Women: Women with CF may face reduced fertility compared to others, but successful pregnancies are still possible. Pregnancy, however, can worsen CF symptoms.

Other Complications:

– Osteoporosis: Individuals with CF are at a higher risk of severe bone thinning, leading to muscle pain, joint discomfort, and arthritis.

– Electrolyte Imbalances and Dehydration: Saltier sweat production can disrupt blood mineral balance, making CF patients prone to dehydration.

– Mental Health Issues: The lifelong management of CF can lead to emotional challenges such as anxiety, depression, and fear.

– Heart Failure due to lung damage, Hemoptysis (coughing up blood), Kidney problems, and Kidney stones are potential complications.

Diagnosing Cystic Fibrosis

Diagnosing Cystic Fibrosis (CF) involves a comprehensive evaluation and various tests for individuals of different age groups, from newborns to adults. These diagnostic tests aim to identify carriers and confirm the presence of the mutated CFTR gene associated with CF. Here are the key diagnostic procedures:

Screening for Cystic Fibrosis:

  1. Carrier Screening for CFTR Mutations: Genetic tests are conducted to determine if an individual carries a mutated CFTR gene. Carriers inherit one mutated gene from one parent but do not have the disease themselves. This testing can be a part of prenatal screening and can utilize DNA samples from blood, saliva, or cheek cells. It often checks for 23 common CF-causing mutations.
  1. Prenatal Screening: Couples planning to have children may undergo genetic screening to check if either partner is a carrier of the CF gene mutation. This can be done before conception or during early pregnancy, involving various sample types like blood, saliva, or cheek swabs. If both partners are carriers, additional prenatal diagnostic tests are considered for the unborn child’s genetic status.
  1. Newborn Screening: Early diagnosis is essential, and most newborns are screened for CF within the first 48 to 72 hours of birth. This screening typically involves measuring immunoreactive trypsinogen (IRT) levels in the blood, followed by DNA testing in some states to identify specific CF-causing gene mutations. High IRT levels can trigger further DNA testing for confirmation.

Diagnostic Tests for CF Confirmation:

  1. Sweat Test: The concentration of chloride ions in sweat is measured using a sweat test, which is a common diagnostic method for CF. It involves applying pilocarpine to the skin to stimulate sweat production, and then collecting sweat for analysis. Results are categorized as normal, likely CF, or borderline, depending on chloride levels.
  1. Genetic Tests: Genetic assays can identify specific CFTR gene mutations. Over 2,000 mutations related to CF have been cataloged, with some being more prevalent than others. Genetic tests are used to confirm carrier status and diagnose CF, especially in families with a history of the disease. Samples are typically obtained from blood or cheek swabs and processed in specialized labs.
  1. Chest X-rays and Sinus X-rays: These imaging tests may be requested by healthcare professionals to support a CF diagnosis, but they are typically complemented by other diagnostic tests.
  1. Lung Function Tests: Spirometry, a lung function test, measures lung capacity and airflow to assess respiratory function.
  1. Sputum Culture: A sputum sample is collected for bacterial analysis to identify specific bacteria commonly found in CF patients.
  1. Nasal Potential Difference (NPD) and Intestinal Current Measurement (ICM): These tests measure ion transfer across nasal and rectal tissues, respectively, using electrodes and specialized solutions.
  1. Other Tests: Additional diagnostic tests may include ultrasound, CT scans, stool tests, secretin stimulation tests, and blood tests for infants who cannot produce sufficient sweat.

Diagnosing CF during early childhood is common, and while the sweat test is a primary diagnostic tool, other tests are employed to confirm CF and assess its severity. Accurate diagnosis is essential for appropriate management and treatment of CF.

Treatment for Cystic Fibrosis

Cystic Fibrosis (CF) requires a comprehensive treatment approach to manage symptoms, minimize complications, and enhance the quality of life for affected individuals. Treatment strategies often include a combination of therapies and medications recommended by healthcare professionals. Here are various treatment approaches commonly used for CF:

  1. Nutritional Therapy:

   – Consultation with a certified dietitian is crucial to address CF-related digestive challenges. Recommendations may include:

   – A high-fat diet to counter nutrient malabsorption.

   – Increased calorie intake to prevent unintentional weight loss.

   – Additional salt consumption to compensate for increased perspiration.

   – Pancreatic enzyme supplements to aid in food digestion and nutrient absorption.

  1. Physical Therapy for CF:

   – Specialized breathing techniques help clear mucus and improve lung function. Common exercises include autogenic drainage, active cycle of breathing, and airway clearance techniques.

   – Chest therapy or percussion, which involves tapping the chest to dislodge mucus.

   – Vibration techniques that use gentle hand motions on the chest.

   – Breathing exercises like positive expiratory pressure and oscillating devices.

  1. Medications:

   – CFTR Modulators: These drugs aim to correct the defective CFTR protein, improving lung function and preventing complications.

   – Bronchodilators to open airways, making breathing easier.

   – Mucus-thinning therapies.

   – Stool softeners, vitamin supplements, proton pump inhibitors, and antiemetics.

   – Antibiotics to treat and prevent lung infections.

   – Pain relievers for symptom management.

  1. Surgeries:

   – In some cases, individuals with CF may require surgeries such as bowel surgery, feeding tube insertion, double lung transplant, or other organ transplants.

  1. Gene Therapy:

   – Gene therapy holds promise for CF treatment, aiming to correct the CFTR gene’s defects. Research in this field continues to advance, offering hope for more effective treatments in the future.

  1. 6. Care and Monitoring:

   – CF patients should avoid environmental triggers like smoke, dust, and fumes.

   – Adequate hydration, regular physical activity, and airway clearance techniques are essential.

   – Patients should refrain from close contact with other CF patients to reduce infection risk.

   – Staying informed about the latest advancements in CF care is crucial for optimal management.

Challenges and Complications:

   – Treatment can lead to side effects, including gastrointestinal discomfort, respiratory symptoms, liver issues, and more.

   – Respiratory complications may arise due to infections or overuse of medications.

   – Managing complex treatment regimens and maintaining adherence can be challenging.

   – Psychosocial challenges and mental health concerns like depression and anxiety may occur.

   – Bone health may be compromised due to medications.

   – Financial burdens and limited access to specialized care can be challenging for CF patients and their families.

   – Lung function decline may still occur despite treatment, potentially requiring lung transplantation.


Cystic Fibrosis (CF) remains incurable, but significant advancements in treatment and care have significantly improved the lives of those affected by this genetic disorder. Several factors, including disease severity and early diagnosis, can influence an individual’s health and the progression of CF.

The median predicted lifespan for individuals born with CF has notably increased over the years. For children born today with CF, life expectancy is expected to be even higher. Notably, those with atypical forms of CF may have a longer life expectancy compared to those with conventional forms of the disease.

Preventing CF is not possible since it is a genetic disorder. However, individuals with a family history of CF may consider genetic counseling before planning to have children. Genetic screening, conducted through a blood test, can provide insights into the risk of passing on the condition to offspring. If pregnancy is already underway and genetic screening indicates a risk of CF, further diagnostic tests can be performed on the unborn baby. It’s essential to weigh the emotional implications of these tests and consult with a genetic counselor before making decisions.

For individuals living with CF, self-care and supportive measures are crucial. Here are some guidelines:

For Parents of Children with CF:

– Consult a dietitian to ensure proper nutrition.

– Encourage physical activity suitable for your child’s health.

– Ensure your child stays well-hydrated.

– Follow airway clearance guidelines.

– Keep up with recommended vaccinations.

Managing the Challenges of CF:

– Focus on your child’s positive qualities and involve them in healthcare decisions.

– Educate yourself about CF to better support your child.

– Do your best while recognizing that you can’t control every aspect of the situation.

For Adults with CF:

– Adhere to prescribed medications and vitamins.

– Perform airway clearance therapies.

– Get recommended vaccines.

– Stay well-hydrated.

– Follow a diet plan developed by a dietitian.

– Engage in aerobic exercise.

– Avoid smoking, vaping, alcohol, cannabis, and other substances.

– Consider joining a CF support group.

– Explore participation in clinical trials for new CF treatments.

Guidance for Healthcare Professionals:

– Provide immediate counseling upon diagnosis, addressing genetic inheritance and future pregnancy risks.

– Educate patients and parents on airway clearance techniques and chest physical therapy.

– Instruct on the correct use of medication delivery devices.

– Discuss when to reach out to CF specialists and address emotional implications for the family.

In summary, while there is no cure for CF, advancements in treatment and care have extended life expectancy and improved the quality of life for those with the condition. Prevention is not possible due to its genetic nature, but genetic counseling can provide valuable information for families. Self-care and support are essential for managing CF effectively, with healthcare professionals playing a vital role in patient education and guidance.

Navigating the Long-Term Journey of Cystic Fibrosis: Considerations and Hope

Advancements in CF care and therapies have significantly increased life expectancy, with many CF individuals now living well into adulthood and beyond. Ongoing research and treatment developments continue to enhance this outlook.

CF lung disease involves the accumulation of thick mucus in the airways, leading to chronic inflammation and lung damage. Regular spirometry monitoring is crucial for tracking changes and guiding treatment to manage this progressive condition.

Long-term respiratory challenges may include chronic infections, permanent lung damage (bronchiectasis), and the potential need for oxygen therapy to maintain optimal oxygen levels in the blood.

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