Did you know multiple genetic changes cause cystic fibrosis?
The ups and downs of cystic fibrosis - Living with a life-threatening genetic condition
“Woe is the child kissed on the brow who tastes salty, for he is cursed and soon must die.” A warning from the Middle Ages about “bewitched” or “hexed” children who tasted salty when kissed, and died soon after birth. The disease described is cystic fibrosis, so named in the 1930s because it leaves a fibrous scar on affected organs. Cystic fibrosis is one of the most common life-threatening genetic diseases, affecting more than 70,000 people around the world. However, unlike in the Middle Ages, today most people with cystic fibrosis live well into their 30s, due to breakthroughs in treatment and management of the disease.
Cystic fibrosis is an inherited disease. It is characterized by the production of extremely salty sweat, and the over-production of sticky mucus in the lungs and the digestive system. It is caused by defects in a single gene called CFTR. The CFTR gene gives instructions to make a channel that controls the movement of salt in the body. Genetic changes in this gene increase the body’s production of mucus, sweat and digestive fluid. Mucus occurs naturally in the body. It covers the lining of organs and tissue, like the lungs and digestive system, lubricating and protecting them from damage. Normal mucus is thin and slippery, but the mucus of people with cystic fibrosis is thick and sticky, and can clog the affected organs. People with cystic fibrosis also make very salty sweat and abnormally thick digestive fluids.
In the early 1960s, the life expectancy of a cystic fibrosis patient was just 10 years. This was extended to 18 in the 1980s, and nowadays cystic fibrosis patients may live well into their fourth decade. However, life is not without its challenges. Major symptoms of cystic fibrosis include frequent lung infections (including pneumonia and bronchitis) and serious digestive problems. Patients have their ups when all systems function normally, but can experience the downs of the disease just a short while later. When things take a turn for the worse, immediate hospitalization is needed.
There is no cure for cystic fibrosis, but many medical discoveries have been made already. There are effective antibiotics like Cayston to prevent lung infections, and drugs like pulmozyme to increase mucus breakdown. Recent developments are also offering renewed hope. The FDA approved the ‘fast track’ clinical trials of a new cystic fibrosis drug, N9115, and a naturally occurring substance (fusicoccin-A) offers great potential as a drug option. Affected individuals can now often hold full-time jobs, run marathons, become professionals, and even start their own families.
Cystic fibrosis is a recessive disorder, meaning that two defective copies of the CFTR gene must be present before disease symptoms occur. Individuals who carry just a single copy of a defective CFTR gene are known as carriers. Carriers are generally unaffected, and often have no knowledge that they carry a defective gene. However, genetic testing is now readily available to accurately detect for multiple disease-causing CFTR mutations. This allows potential cystic fibrosis carriers to understand their risk of having a child affected by this debilitating condition.