Cystic Fibrosis Birth Defect
Children born with cystic fibrosis have an overabundance of mucus, which can clog up the lungs, lead to infections, and create difficulties with digestion and growth. Cystic fibrosis is usually be identified with prenatal testing.
In the United States, around 30,000 people have CF. It occurs in 1/3500 births.
How Is Cystic Fibrosis Inherited?
Cystic fibrosis is a birth defect that occurs whenever someone inherits the "CF gene" from both of their parents.
Cystic fibrosis is an example of an autosomal recessive inheritance. This means that the disease is caused by inheriting two copies of a mutated gene, one from each parent. People who inherit only one copy of the mutated gene are called carriers and do not have the disease but can pass it on to their children.
The CF gene question controls the production of a protein called CFTR. This protein is responsible for maintaining the balance of salt and water in the body's cells. In individuals with cystic fibrosis, this protein is either missing or does not function properly, resulting in the production of thick and sticky mucus in the lungs, digestive tract, and other parts of the body. The symptoms of cystic fibrosis vary in severity but commonly include chronic lung infections, difficulty breathing, poor growth, and digestive problems.
What Are the Symptoms of Cystic Fibrosis?
Cystic fibrosis is usually diagnosed with a child is very young. The primary symptoms are respiratory infections and poor weight gain.
When mucus builds up in the lungs, the tubes which normally allow the free flow of air become blocked, and this can create difficulties with breathing. As a result, persistent coughing with thick mucus or shortness of breath may result. These symptoms can also be accompanied by breathlessness, intolerance for exercise, or a stuffed-up nose.
The buildup of mucus can also lead to frequent lung infections, including pneumonia or bronchitis. Other complications may include damaged airways (bronchiectasis), growths in the nose (nasal polyps), coughing up blood, and gradual respiratory failure over time.
As for the digestive system, the build-up of mucus can block the passageway which transports digestive enzymes from the pancreas to the small intestine. As a result, limited growth or weight gain despite a good appetite is a prominent symptom of cystic fibrosis, due to inadequate nutritional absorption.
One symptom of a child born with cystic fibrosis is severe constipation or especially greasy or foul-smelling stools. In newborns, it is also important to keep an eye out for intestinal blockage or rectal prolapse, as these may also be a sign of cystic fibrosis. Due to the blockage of the passageway from the pancreas, the transport of insulin may also be blocked which can lead to the development of diabetes as a complication. Furthermore, the tube that carries bile from the liver and gallbladder to the small intestine can also become blocked and inflamed, which may lead to liver problems or gallstones.
Other symptoms that may arise with cystic fibrosis include
- bone-thinning (osteoporosis)
- increased levels of salt in sweat and the skin
- electrolyte imbalances in the blood (which can result in dehydration, fatigue, weakness, low blood pressure, and an increased heart rate)
- reproductive system complication that impairs fertility (especially in men)
The severity and occurrence of symptoms may differ wildly.
Today, most children in the United States are screened for cystic fibrosis at birth. Although this screening will not always catch cystic fibrosis, it is an important first step and can detect the disease even if your child is pre-symptomatic.
If your child is showing some of the symptoms of cystic fibrosis, your doctor should recognize this during a clinical evaluation and order additional testing - such as a sweat test and a genetic test - to confirm the diagnosis. Through the combination of these procedures, most cases of cystic fibrosis are diagnosed by age 2.
Unfortunately, cystic fibrosis may be misdiagnosed and could lead to the condition being misdiagnosed as something else such as asthma, or symptoms such as pneumonia may be accurately diagnosed without recognition of the underlying cause.
Unfortunately, there is no medical "cure" for cystic fibrosis. Although no cures for cystic fibrosis are known, treatments which have been developed in the last century are capable of maximizing organ function and helping to protect against life-threatening complications. The most beneficial therapies for your child should be determined by their physician based on their unique needs. The majority - but not all - of these therapies are typically administered daily.
For the Digestive System:
- Enzyme pills administered with/before meals can help the body improve absorption of key nutrients during digestion
- Multivitamins also help ensure adequate nutrition
- For cystic fibrosis-related diabetes, a typical treatment regimen should also be prescribed
For the Lungs:
- Airway Clearance: There are multiple methods which can help clear up the airways of your child's lungs to help them breathe. Some of the most common methods include physical therapy and a machine-connected vest which shakes (usually for 30 min/day) to loosen up the mucus.
- Medication: There are medicines that help improve lung health. Some are inhaled medications that help clear up airways and thin mucus. These medications may include antibiotics to ward off infection. Anti-inflammatory drugs can also help limit the progression of the disease.
- Lung transplants
Other treatments include:
- A personalized fitness plan, which can help improve lung function, energy, and overall health
- CFTR modulators - these are drugs specifically designed to target the CF gene but are limited in applicability because they only work for specific mutations
- Fertility treatments and surgical procedures can sometimes enable men with cystic fibrosis to become biological fathers
- Durda-Masny, M., et al (2021). The determinants of survival among adults with cystic fibrosis—a cohort study. Journal of Physiological Anthropology, 40(1), 19. https://doi.org/10.1186/s40101-021-00276-2. The study aimed to investigate the relationship between severity of mutation, nutritional status, lung function, and Pseudomonas aeruginosa prevalence and survival rate in adult patients with cystic fibrosis (CF). The researchers found that all factors included in the study were significantly related to the survival rate of patients with CF. Patients with a mild mutation on one allele or both alleles lived longer than subjects from the group with severe types of mutation on both alleles. The study highlighted the problem of serious pulmonary exacerbations occurring between the ages of 20 and 40, and the most critical life period in adults with CF characterized by a severe type of mutation falls within the age range of 20 to 30 years. The presence of P. aeruginosa decreases average life expectancy, and undernutrition is a significant factor in the CF adult lifespan.
- Becq, F., et al. (2021). The rescue of F508del-CFTR by elexacaftor/tezacaftor/ivacaftor (Trikafta) in human airway epithelial cells is underestimated due to the presence of ivacaftor. European Respiratory Journal, 58(1), 2100671. doi: 10.1183/13993003.00671-2021. Trikafta, a triple combination therapy of two folding correctors, elexacaftor/tezacaftor, and the gating potentiator ivacaftor, is a leading therapeutic treatment for cystic fibrosis (CF). Doctors and patients have found clincial benefits with Trikafa. This study aimed to compare the properties of Trikafta in cells treated with lumacaftor, tezacaftor, elexacaftor, elexacaftor/tezacaftor with or without ivacaftor. These authors believe that ivacaftor reduces the correction efficacy of Trikafta, and combining elexacaftor/tezacaftor with a different potentiator might improve the therapeutic efficacy for treating CF patients.
- Boyd, C.A., et al. "New approaches to genetic therapies for cystic fibrosis." Journal of Cystic Fibrosis 19 (2020): S54-S59. This study looked at novel gene therapy approaches to cystic fibrosis treatment. They included viral and non-viral delivery approaches, oligonucleotide and siRNA approaches to gene silencing and splicing, and CRISPR and mRNA gene editing. Ultimately, cystic fibrosis is a gene defects and the researchers underscore the great promise that genetic therapy treatments might have on the lives of cystic fibrosis patients. Many people do not realize that there are gene editing companies, like Metagenomi, that identify and evaluate novel gene editing systems in the search for new therapeutics to treat CF.
- Cuthbertson, L., et al. "Lung function and microbiota diversity in cystic fibrosis." Microbiome 8 (2020): 1-13. This study looked at whether microbiota diversity and lung function indicated cystic fibrosis severity. The researchers found that decreased microbiota diversity correlated with decreased lung function. They also found that CF pathogens dominated in reduced lung function cases. The researchers concluded that microbiota diversity and dominant bacterial species, when combined with lung function, were “informative indicators” of CF severity.
- Mooney, C., et al. "Plasma microRNA levels in male and female children with cystic fibrosis." Scientific Reports. 10.1. (2020): 1-8. This looked at the gender gap in the expression profiles of cystic fibrosis patients under six years old. The researchers found an increase in the miR-885-5p gene in female patients’ plasma compared to males. They concluded that this result warranted additional studies to determine the gene’s usefulness in monitoring the disease and whether the gender gap indicated functional differences.
- Rafeeq, M.M. & Murad, H.A.S. "Cystic fibrosis: current therapeutic targets and future approaches." Journal of Translational Medicine. 15.1. (2017): 1-9. This review examined cystic fibrosis treatments. The authors reported that the main treatment focuses went from improving symptoms and complications to correcting functional and structural abnormalities. They also observed improvements in corrector drugs, gene therapy, cellular interactome targeting, and newer symptomatic improvement drugs. Nonetheless, the researchers underscored the sober reality that cystic fibrosis treatments have “a long way to go” because many of the existing treatments were for older children. There is clearly a need, the authors convincingly argue, for novel approaches such as gene editing, disease modeling, and searching for alternative targets.
- Stephenson, A.L., et al. "Survival comparison of patients with cystic fibrosis in Canada and the United States: a population-based cohort study." Annals of Internal Medicine. 166.8 (2017): 537-546. This study compared and contrasted survival rates among American and Canadian cystic fibrosis patients. The researchers found that the median survival age in Canada was 10 years higher than in the United States between 2009 and 2013, while the adjusted death risk was 34 percent lower. They concluded that cystic fibrosis survival differences persisted after adjusting for all associated risk factors except for privately insured Americans. The researchers also concluded that lung transplant access, post-transplant survival, and health care system differences explained the higher survival rates among Canadian cystic fibrosis patients.