Main Information That Is Related To The Cystic Fibrosis

Description

Cystic Fibrosis is a genetic disease that causes inefficient osmosis into the alveoli causing the mucus to become heavy and thick. Due to this, people suffering from this disease have trouble removing dust and bacteria from their lungs and Trachea. Small hair strands in your throat, called cilia, waft upwards and out of your windpipe. This wafting effect is useful for pushing mucus out of your throat. The whole point for mucus is to trap bacteria and dust from reaching the alveoli cell’s membranes. Whilst the mucus is pushed up and out of your throat, it carries all the pathogens and dust along with it to be deposited into the highly acidic stomach; killing all the bacteria. Due to the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene mutation, the mucus is now thick making it harder to exit the trachea and cause food digestion problems since it starts to clog the pancreas.

Symptoms

• Recurring chest infections
• Bronchiectasis
• Wheezing, coughing, shortness of breath
• Difficulty putting on weight and growing
• Jaundice
• Diarrhea, constipation
• Meconium Ileus

Types of Mutations

CFTR mutations have been divided into 6 categories. Class-1 includes nonsense, most frameshift, and large deletions which cause premature stop codon resulting in defective protein synthesis and no CFTR protein is expressed. Class-II includes some missense mutations and in-frame deletions that disrupt the CFTR protein folding. Misfolded protein is not transported to the cell surface. Class-III includes some missense mutations resulting in the substitution of amino acids disrupting the regulation of the CFTR channel. This means reduced or lack of CFTR channel opening. Class-IV includes some missense mutations which result in changes to the CFTR protein structure that forms the pores of the CFTR channel. The misshaped CFTR pores can restrict the Cl- ions through the channel. Class-V includes the missense mutations resulting in alternative splicing that disrupt the mRNA processing. Due to this very small amount of CFTR protein is synthesized. Class-VI includes different types of mutations that increase the turnover of CFTR protein on the cell surface. In this case, the CFTR protein is unstable and gets quickly degraded. One example is the delta F508 gene mutation which involves the deletion of the 508th triplet (hence the name delta F508). This specific mutation is responsible for 70% of all cystic fibrosis cases.

Effects

Cystic fibrosis is associated with very frequent coughing for the patients, blistering the alveoli and throat. The mucus becomes thick as the delta F508 gene mutation induces the chlorine concentration to increase on the inside of the cell, as shown in the diagram above. Due to this, osmosis causes the water to rush into the cell, leaving the outside of the cell with a very low water concentration and making the mucus dense and viscous.