Friday, 26 February 2016

Cystic Fibrosis

Cystic fibrosis is a genetic condition where the lungs and digestive system are clogged by mucus. It is the second most life-shortening inherited disorder in the United  States, proving its seriousness. The symptoms include persistent coughing, recurring lung infections and poor weight gain.


Cystic fibrosis can be identified by screening new-borns. By taking a small blood sample from the baby's heel, eight other conditions as well as cystic fibrosis can be identified. For adults, a pregnant woman can certify whether their developing foetus has the faulty gene by passing a fine needle into the womb. This action, known as antenatal testing, is carried out if the condition is common in the mother's ancestry. A piece of developing placenta is removed to examine its chromosomes.
New-born screening
The Chloride Channel
For a quicker diagnosis, by tasting the sweat of a baby, saltiness would indicate cystic fibrosis. This is due to a defect in the CFTR gene, which not only causes cystic fibrosis, but is used to synthesise the protein (cystic fibrosis transmembrane conductance regulator) involved in the movement of salt in cells. Defective CFTR triggers poorly synthesised genes, causing mucus to form and very salty sweat. This is due the chloride channel being altered in stability and structure, preventing transport of chloride ions and therefore water into and out of cells.  The build up of these ions causes the cells lining the lungs and other organs to form mucus.

The CFTR defect is recessive, therefore if both parents are carriers, there is a 25 per cent chance that the child will inherit the condition.

Diagram of CF inheritance
(National Institute of Health, 2017)
Recurring lung infections are also suffered by cystic fibrosis sufferers. Often due to the mucus build-up, as it provides ideal conditions for bacterial habitation. Treatment with antibiotics raises the issue of resistant bacteria developing and as a result contact between sufferers, since they are the most vulnerable, must be kept at a minimal.

As well as the mucus lining the lungs, it can also line the organs involved in the digestive system. If the pancreas ducts are blocked, pancreatic insufficiency can occur. This means that it cannot perform its endocrine functions, including the secretion of essential enzymes needed for digestion. Therefore, often sufferers are unable to absorb the nutrients and metabolize them properly, leading to malnutrition.

Unfortunately, there is no cure for the condition. Sufferers can be treated with antibiotics to fight lung infections, and increase immunity through flu jabs . To thin down the mucus, the enzyme Pulmozyme is issued, which breaks down the mucus so that it can then be coughed up. A strict diet consisting of high calorie foods, rich in fat and protein, must be followed as well to prevent malnutrition. Capsules containing essential enzymes are also taken to help digestion if the pancreas is inert due to mucus build up. Those with breathing problems may also use bronchodilators, a form of gaseous medication which helps keep the airways open by relaxing the muscles around the bronchial tubes.
References:
nhsuk(2016). wwwnhsukRetrieved 26 February, 2016, from http://www.nhs.uk/Conditions/cystic-fibrosis/Pages/Introduction.aspx

Webmdcom(2016)WebMDRetrieved 26 February, 2016, from http://www.webmd.com/lung/what-is-cystic-fibrosis

Cfmedicinecom(2016)CfmedicinecomRetrieved 26 February, 2016, from http://www.cfmedicine.com/htmldocs/CFText/basicproblem.htm

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