- Nathan Fry
By: Nathan Fry, Contributing Writer
Edited by: Olivia Storti, Editor; Elias Azizi, Editor in Chief
Cystic Fibrosis, commonly denoted as CF, is an autosomal recessive disorder, which is most common within caucasian populations, being diagnosed in around 1 in every 3,000 white newborns, though significantly less within other demographics. It is estimated by the Cystic Fibrosis Foundation, that around 30,000 people in America are living with it, as well as 70,000 CF patients worldwide!
But what causes cystic fibrosis? As an autosomal recessive disorder, cystic fibrosis is a genetic condition, which can be obtained when both parents have the recessive gene in which CF is derived: more specifically, it is a mutation in the CFTR gene in the 7th chromosome. This disorder follows the autosomal recessive inheritance pattern, stating that if both parents are carriers of the gene which causes CF, there is: a 25% chance that the child will have CF; a 50% chance that the child will not have CF, but will be a carrier of the CF gene; a 25% chance that the child will neither have CF, nor the gene. However, if one of the parents has cystic fibrosis, this changes, meaning that there will instead be: a 50% chance that the child will have cystic fibrosis; and a 50% chance that he will be a carrier of the CF gene. People with CF are born with the condition, and it cannot be passed on in any other way other than through conception.
The CFTR (or cystic fibrosis transmembrane conductance regulator) mutation causes an issue with CFTR proteins, which act as gateways in and out of cells, by which ions move out of. These proteins are distinctly prominent in mucus-producing layers of tissue, including those found throughout the digestive system, pulmonary system and within other organs of the body. The transportation of ions is crucial on a cellular level, as they dictate the movement of water intracellularly by osmosis.
If chloride ions are unable to leave the cell, a variety of problems can occur, including how a greater negative charge is formed on the outside of the cells than within, creating a potential difference which can be life-threatening within cardiac tissue. Moreover, if chloride ions are unable to leave cells, this means that water won’t be attracted to mucus outside of the cell, causing it to be more viscous. This makes it more challenging to catch bacteria and other pathogens, which is then waved by ciliated epithelial cells to be discarded by your body, as well as causing your cells to swell in a hypotonic solution. This, therefore, also thickens the lining of organs, such as the stomach and pancreas, meaning people with CF are more likely to develop pancreatitis or stomach ulcers, and/or have deficiencies or malnutrition.
Some symptoms of cystic fibrosis, according to the NHS website, include:
Recurring chest infections
Wheezing, coughing, shortness of breath and damage to the airways (bronchiectasis)
Difficulty putting on weight and stunted growth
Yellowing of the skin and the whites of the eyes (jaundice)
Diarrhea and constipation
Bowel obstruction in newborns (meconium ileus)
However, recognising symptoms is not the only way to effectively diagnose CF today. In the UK, every baby has to have a blood spot test at 5 days old, which takes a 4-drop blood sample to test for 1 of 9 rare but serious health conditions, including CF and sickle cell disease. These early screenings and treatments are crucial to improve health, and prevent severe disability or death. Furthermore, there are also genetic testing kits that can be bought online or performed at a general practitioner’s practice which can highlight any serious markers for genetic disorders for parents who are planning on raising a family. Also, due to the inability of people with CF to reabsorb chloride ions from sweat, this means that healthcare professionals are also able to test the amount of salt and ions that are present in sweat, which will be abnormally high in someone with cystic fibrosis.
Despite how harsh this disability is, a variety of medications and therapies are being used and continuously developed in order to treat, though not cure, and manage the symptoms of people with CF. For pneumococcal and lung issues caused by CF, there are a plethora of medications that can be used, including antibiotics to prevent and treat recurring infections, medications to thin mucus in the trachea and bronchodilators which widen and clear airways, making it easier to breathe, as well as medications to treat the root cause of cystic fibrosis. In terms of therapies, it has also been proven that exercise, diet and airway clearance techniques also help to manage the symptoms of cystic fibrosis.
Link to cover image: https://www.eatright.org/-/media/eatrightimages/health/diseasesandconditions/gettyimages-590276922.jpg?h=450&w=600&la=en&hash=51BC6E0F518A2E593EB9AC19288D3430FDF23509
Autosomal recessive inheritance pattern - Mayo Clinic
Cystic fibrosis: MedlinePlus Genetics.
Cystic fibrosis: pathology review