Cystic Fibrosis

Written By: Maitri Paresh Vanar, Class Of 2028

This blog is about cystic fibrosis, a genetic disorder affecting mucus production, its symptoms, diagnosis, and the CRISPR/CAS 9 experimental approach.

INTRODUCTION:

Cystic fibrosis is a genetic disorder which means it is passed from a generation to next generation.

It affects the way our body produces mucus. A normal mucus is thin and slippery but a CF infected person’s body produces thick and glue like mucus which may block tube and ducts throughout the body.

It’s a rare genetic disorder, lungs are most likely to be affected but also the pancreas, liver, kidneys and intestine. It is caused by the presence of mutations in both alleles of the gene encoding the cyctic fibrosis transmembrane conductance regulator protein (CFTR).

When CFTR protein is non-functional, secretions become thick which should be thin normally. If a person inherits only one copy then they will be a carrier of the disease and won’t have any symptoms.

SYMPTOMS:

New borns and infants with this disorder are underweight for their age and have frequent greasy stools as a result of malabsorption. It is typically manifested early in life.

Children with cystic fibrosis experience excessive salt loss in their sweat. Their parents may often notice salt crystallizing on their skin or get a salty taste when they kiss their child.

People with cystic fibrosis experience death due to progressive lung disease which eventually leads to respiratory failure. In individuals with cystic fibrosis, the majority experience chronic respiratory tract infections, with the presence of pseudomonas aeruginosa, fungi, and mycobacteria becoming increasingly common over time.

The upper airway inflammation often results in recurring nasal congestion and a frequently runny nose. With the advancement of the condition, individuals commonly encounter breathlessness and develop a persistent cough accompanied by production of sputum.

DIAGNOSIS:

In many countries, newborns are screened for CF shortly after birth which involves blood test or a genetic test to identify certain mutations associated with CF.

The sweat test is one of the good diagnostic test for CF, usually performed on infants older than two years of age and adults. It measures the amount of salt in sweat and thus detects the CF if the person has a higher level of chloride .

A genetic testing can also be done to identify specific mutation in the CFTR gene responsible for CF. Its usually useful when other diagnostic tests are inconclusive. Additional tests such as respiratory function tests, sputum culture to identify specific bacteria or fungi, pancreatic function tests, gastrointestinal evaluations, and liver function tests can also be performed.

 CRISPER/CAS 9: AN EXPERIMENTAL APPROACH:

The arrangement of the four bases in DNA holds the key to our individuality and is inherited from one generation to the next, encompassing all our biological information.

Due to the inability of DNA to leave the nucleus, the instructions required for protein synthesis are transcribed or duplicated into RNA.

DNA possesses a unique characteristic of self-replication during cell division, which is crucial for ensuring that each new cell maintains an identical DNA sequence to its parent cell.

In the event of a mutation in the DNA, this error is propagated to both RNA and the resulting protein. CF is a hereditary disorder resulting from a mutation in the gene responsible for producing the cystic fibrosis transmembrane conductance regulator (CFTR) protein.

In healthy individuals, CFTR proteins act as channels, facilitating the movement of water and charged ions, such as chloride, across cell membranes.

This process helps generate a protective thin layer of mucus and lubricates internal organs (like the lungs and pancreas) the presence of faulty CFTR protein disrupts the normal flow of water and ions in and out of cells, causing the accumulation of thick mucus that obstructs the airways and ensnares bacteria.

Due to this factor, individuals with CF frequently experience chronic inflammatory responses and recurrent infections. CF therapies can target DNA, RNA, or proteins, but only at the DNA level can the mutated CFTR gene be replaced and CFTR function be restored.

CONCLUSION:

Living with CF can be challenging, but advancement in research and treatment offer hope. Support organizations and resources are available to provide information and support. Let us strive to raise awareness about CF, together we can make a difference in the lives of those affected by this condition and work towards a future where CF is better understood and managed.