Cystic Fibrosis Mutation and Its Consequences

Introduction

Cystic fibrosis is an illness that affects the digestive system and the lungs, and it is one inherited along with a given family’s genetic makeup. It results in massive production of sticky and thick mucus, leading to pancreas obstruction and lung clogging. Most people with the condition tend to have shorter life spans due to its life-threatening nature. Furthermore, the disease has no cure, which only makes it more fatal. However, proper nutrition and appropriate steps to enhance mucus expectoration and mucus thinning can be significant. It falls in the same group as Tay-Sachs, hemochromatosis, and sickle cell anemia because single mutated genes cause them. This means that various mutations can lead to a similar condition but with different phenotype and severity degrees. In this regard, the paper looks at cystic fibrosis’s biochemical basis to understand the nature of the mutation, its consequences, and any known interventions or treatments.

Nature of Mutation

All human beings have two copies of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. However, to get infected with cystic fibrosis, they must inherit a copy from both parents (Brennan and Schrijver, 2016). Nonetheless, if one inherits a regular copy and contains a mutation, he/she is considered a carrier (Wei et al., 2020). Such individuals do not have the condition, but they can pass a copy of the defective gene to their children (Elborn, 2016). Therefore, cystic fibrosis is caused by mutations in the gene-producing CFTR protein. The protein is essential for the salt and fluids regulations in and out of cells across the body.

CFTR gene mutations can disrupt the normal functioning or production of the CFTR protein present in lung cells and the rest of the body. CFTR gene is responsible for instructions that lead to creating the channel for transportation of negatively charged chloride ions (Elborn, 2016). With these mutations, the channels’ functioning gets disrupted, and the cells in the pancreas, lungs, and other organs’ passageways produce unusually sticky and thick mucus (Elborn, 2016). However, there are still over 2000 reported cystic fibrosis variants (Brennan and Schrijver, 2016). Among these, 40% are believed to cause single amino acid substitution; another 26% alter RNA processing, 3% involve CFTR rearrangements, 14% are neutral variants, 1% affect promoter regions, while 6% of these have unclear effects (Brennan and Schrijver, 2016). These variants are what lead to the various classifications of CFTR.

System Group Classification

CFTR variants are grouped into five classes to establish a credible framework for primary defect understanding at cellular levels. The binning of these variants into a single class is often problematic as the given alteration can distort various processes. For instance, F508del leads to CFTR aberrant folding followed by synthesized protein degradation (Naehrig, Chao, and Naehrlich, 2017). Moreover, these changes lead to translation efficiency reduction, which leads to CFTR functioning changes. These effects are essential as they underpin the nature of the mutation at the level of DNA for cystic fibrosis.

Protein Production Mutations (Class 1)

These include splice and nonsense mutations, and they alter CFTR protein production. All body proteins are made of building blocks linked into a long chain referred to as amino acids. They provide instructions that direct the CFTR gene to establish which of the available 20 amino acids to be used in given positions, including when to start and stop (Naehrig, Chao, and Naehrlich, 2017). Splice mutations interfere with these instructions, making the cell unable to read them, leading to an incorrect CFTR protein building.

Protein Processing Mutations (Class II)

CFTR has 1480 amino acids, making it form a 3-D shape that is essential for chloride transportation. DNA mutation may cause the addition of an incorrect amino acid or deletion, which inhibits its functionality. The most common cystic fibrosis is the F508del which deletes one amino acid from the CFTR protein, and thus it is unable to be in its correct 3-D shape (Naehrig, Chao, and Naehrlich, 2017). When the cell recognizes this, it is disposed of, and transportation cannot occur as a result.

Gating Mutations (Class III)

The CFTR protein is tunnel-shaped, with a gate opened when there is a need for chloride to flow. Gating mutations lead to this gate’s locking, which makes it impossible for chlorides to flow as intended through the desired channel (Naehrig, Chao, and Naehrlich, 2017). This is because the given cell has its DNA altered, and thus, it cannot efficiently and effectively instruct the channel to open the gate for its chloride ions to be moved.

Conduction Mutations (Class IV)

In certain instances, one of the CFTR amino acid changes might fail to function as required even if the protein makes the desired 3-D shape. If it works appropriately, chlorides have to be moved smoothly and quickly through the open channel (Naehrig, Chao, and Naehrlich, 2017). However, the DNA mutations alter the tunnels’ shape, making it impossible for the chloride to move with the intended ease and speed. This form of modification is referred to as conduction though it is one of a rare kind.

Insufficient Protein Mutations (Class V)

These mutations lead to the reduction of normal CFTR from the usually required amounts at the cell surfaces. This arises due to decreased number of proteins working adequately on cell surfaces, limited production of CFTR protein, or quick degradation of normal protein at cell surfaces leading to small protein numbers left behind (Naehrig, Chao, and Naehrlich, 2017). In each of these cases, insufficient proteins are produced on the surface, leading to the chloride channel’s residual functionality.

Phenotype Outcomes

Patients with cystic fibrosis portray clinical phenotypes primarily due to their effects on the digestive, respiratory, and reproductive systems. As such, they may lead to infertility in men, chronic lung illnesses, and gastrointestinal tract alterations (Rafeeq and Murad, 2017). This is because the condition phenotype comprises complex multi-organ alterations analyzed in line with the varied clinical components. These outcomes show the subtlety of the relationship that exists between phenotypes and genotypes.

Consequences and Linkage of the Mutation

Consequences

Cystic fibrosis mutation has the prime effect of clogging organs and the production of thick mucus. These two lead to a particular undesired impact on the organism’s body. As aforementioned, the main organs affected are the pancreas, lungs, and intestines (Rafeeq and Murad, 2017). This leads to poor growth, malnutrition, breathing difficulties, constant respiratory infections, and chronic lung disease. Nonetheless, these consequences depend on age and the particular system where the mutation is most predominant.

On the one hand, for newborns, these consequences include salty-tasting skins, delayed growth, inability to gain weight, and a lack of bowel movements between the first two days after birth. On the other hand, the effects explicitly related to bowel function include loss of appetite and nausea, weight loss, and severe constipation (Rafeeq and Murad, 2017). It also leads to bloating as a result of a distended belly from increased gas. There is also the impact on sinuses and lungs, including fatigue, episodes of pneumonia, pressure, and nasal congestion. In the long term, the condition causes clubbed fingers, pancreatitis, infertility in men, and certain respiratory conditions (Ramsey, Downey, and Goss, 2019). Due to its effects on specific critical body organs, individuals rarely survive the consequences.

Linkage

Cystic fibrosis arises from errors in the CFTR gene resulting in malformed or no CFTR protein production. With the inappropriate function of the CFTR protein, the fluids and chloride balance is disrupted. This leads to sticky and thick mucus production in various body organs (Ramsey, Downey, and Goss, 2019). Consequently, it results in lung infections that advance, leading to the respiratory system’s failure, improper digestion, and reproductive system issues. This linkage arises because the mutations lead to the CFTR protein’s malfunctioning (Wei et al., 2020). Moreover, the mutations lead to chloride ions’ inappropriate movement without which water cannot correctly hydrate cellular surfaces. The linkage mainly arises from the production of thick and sticky mucus covering the cells, which is the primary cause leading to the symptoms of the condition (Ramsey, Downey, and Goss, 2019). Additionally, this is evidence of its recessive nature, meaning that both genes in the inherited pair have to be abnormal for the illness to be experienced.

Treatments or Interventions

Cystic fibrosis has no known cure, but specific interventions or treatments help ease the symptoms, reduce the nature of complications, and ultimately enhance the quality of life and well-being. This is why it is essential to monitor its symptoms early closely and adopt aggressive measures to slow its progression to improve the chances of longer and healthier life (Edmondson and Davies, 2016). However, the treatment measures are complicated. It is essential to seek help from a healthcare facility with a multispecialty team trained in its evaluation, diagnosis, and treatment (Edmondson and Davies, 2016). The therapy aims mainly to control and prevent infections that present themselves in the lungs, loosen and remove the thick sticky mucus, improve nutrition, and prevent and treat intestinal blockage (Edmondson and Davies, 2016). When these goals are achieved, a patient has an increased chance of survival.

Medications

Most patients living with the disease survive on a variety of medication options. Mainly, some target gene mutations include emerging medications. These combine drugs to provide treatment to CFTR by providing modulators (Wei et al., 2020). These modulators help enhance the CFTR protein functionality, which consequently improves the weight, and lung functionality and reduces salty amounts in the body (Edmondson and Davies, 2016). Additionally, their antibiotics are tailored to prevent and treat lung infections. There are also drugs available for liver disease, acid-reduction, stool softening, and mucus-thinning (Edmondson and Davies, 2016). The patients can also be given oral pancreatic enzymes to boost nutrient absorption and bronchodilators for opening airways and relaxing bronchial tube muscles (Edmondson and Davies, 2016). The various options are tailored to mitigate given undesired symptoms, and they help the patients live comfortably with their effects.

Airway Clearance Options

Additionally, there are airway clearance techniques called chest physical therapy (CPT). They aid in the relief of mucus obstruction and enhance the reduction of inflammation and infection along the airways (Brown, White, and Tobin, 2017). The procedures are often done various times daily, and different techniques can be chosen depending on the extent of infection though a combination is recommended. These include the use of mechanical devices such as a vibrating vest, cupping hands while clapping, vigorous exercise, and coughing and breathing procedures (Brown, White, and Tobin, 2017). However, one’s physician needs to advise the given technique and frequency of therapy.

Pulmonary Rehabilitation

A physician may also recommend a program that enhances lung functioning and overall well-being in the long term. However, these programs are always done on an outpatient basis and may include support and counseling, physical exercise, education on the condition, breathing techniques enhancement, and nutritional counseling (Edmondson and Davies, 2016). The success of these approaches often depends on the patient’s dedication and willingness, as a lack of either may render the efforts of the caregiver rather useless.

Surgical Procedures

Apart from the three options, some surgeries are always recommended when the condition becomes chronic. The surgeries are recommended depending on the adverse symptom shown by the patient. For instance, nasal and sinus surgery can be done to remove nasal polyps and treat chronic sinusitis. Additionally, bowel surgery can be done to repair bowel blockage or even intussusception (Edmondson and Davies, 2016). There is also the option of oxygen therapy, lung, and liver transplant, which helps mitigate the effects of the infection on the given organs.

Conclusion

Single gene disorders continue to pose grievous threats to human beings’ lives due to the lack of known cures. Parents need to test themselves before they have children to ensure that they know whether they are carriers or not. If this is done, then interventions will be put in place early enough for newborns. Nonetheless, those already living with these conditions, such as those with cystic fibrosis, need to stick to the medications prescribed by their physicians. However, there is a need for governments to invest in research concerning these conditions to enhance the discovery of better management techniques and cures.

Reference List

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Brown, S., White, R. and Tobin, P., 2017. ‘Keep them breathing.’ Journal of the American Academy of Physician Assistants, 30(5), pp.23-27.

Edmondson, C. and Davies, J., 2016. ‘Current and future treatment options for cystic fibrosis lung disease: latest evidence and clinical implications.’ Therapeutic Advances in Chronic Disease, 7(3), pp.170-183.

Elborn, J., 2016. ‘Cystic fibrosis.’ The Lancet, 388(10059), pp.2519-2531.

Naehrig, S., Chao, C. and Naehrlich, L., 2017. ‘Cystic fibrosis.’ Deutsches Aerzteblatt Online, 33(34), pp.564-574.

Rafeeq, M. and Murad, H., 2017. ‘Cystic fibrosis: current therapeutic targets and future approaches.’ Journal of Translational Medicine, 15(1), pp.99-109.

Ramsey, B., Downey, G. and Goss, C., 2019. ‘Update in cystic fibrosis 2018.’ American Journal of Respiratory and Critical Care Medicine, 199(10), pp.1188-1194.

Wei, T. et al. (2020) ‘Research advances in molecular mechanisms underlying the pathogenesis of cystic fibrosis: from technical improvement to clinical applications (Review).’ Molecular Medicine Reports, 22(6), pp.4992-5002.