Cystic Fibrosis
Cystic Fibrosis is the most common lethal genetic disease in the U.S. that causes severe damage to the lungs and digestive system. It is an inherited disease that affects the cells that produce mucus, sweat and digestive juices. In affected individuals, the body produces mucus that is abnormally thick and sticky, so instead of acting as a lubricant, the mucus plugs up tubes, ducts and passageways, especially in the lungs and pancreas. As a result, a person living with cystic fibrosis may have difficulty digesting nutrients and the mucus build up can lead to bacterial infections in the lungs. The modern history of cystic fibrosis begins in 1938 when Dr. Dorothy Andersen, a pathologist at the New York Babies Hospital, provided the first clear description of cystic fibrosis. There have also been reports of babies who almost certainly had this disease before this time. In 1857 a passage in the 'Almanac of Children's Songs and Games from Switzerland' warned that 'the child will soon die whose brow tastes salty when kissed'. This was proven in 1953 when Paul di Sant'Agnese revealed that patients living with cystic fibrosis had increased salt content in their sweat.
Cystic fibrosis can’t be caught or developed through environmental or bacterial factors. All symptoms of cystic fibrosis are caused by a mutation to chromosome 7. This gene is responsible for the building of the protein called the Cystic Fibrosis Trans Membrane conductance regulator (CFTR). A defect in the CFTR gene has to occur in order to obtain cystic fibrosis. This CFTR gene makes a protein that controls the movement of salt (chloride ions) and water in and out of your body's cells. In cystic fibrosis, the said protein is defective. The result of the faulty protein is thick, sticky mucus in the respiratory, digestive and reproductive systems, as well as very salty sweat (the loss of the CFTR does not allow the body to reabsorb the sodium ions making a cystic fibrosis patient’s sweat five times saltier than that of a normal person). More than a thousand different defects can alter this gene. The severity of the disease depends on these defects. Each person inherits one CFTR gene from each parent. In order to be diagnosed with the disease, a child needs to inherit one faulty gene (recessive gene) from each parent. Children with one normal gene and the other one faulty are cystic fibrosis carriers. Carriers are symptom-free and live normal lives, however they can probably pass their affected gene to their children. There are several different ways to diagnose patients that have cystic fibrosis. The first method is newborn testing. All states routinely screen newborns using a blood test or a genetic test. The blood test is performed to show whether the newborn has a properly working pancreas. In this test a blood sample is taken to check for higher levels of immunoreactive trypsinogen (IRT). In some cases, the newborn was born premature or there was a stressful delivery and the IRT levels may be high, then a genetic test or a sweat test is done to confirm. The genetic test is done to see if the newborn has the affected CFTR genes. If the genetic test suggests cystic fibrosis, a doctor will finally confirm the diagnosis using a sweat test. This is also the most useful test when diagnosing newborns and other patients. For the sweat test, a sweat-producing chemical is applied in a small patch of skin. The test is usually done twice and when the infant is a month old to make certain that the sweat sample is large enough to be analyzed. The sweat is then tested for higher levels of salt. Higher than normal levels of salt confirm a diagnosis of cystic fibrosis. Cystic fibrosis tests may be recommended for older children and adults who weren't screened at birth. Your doctor may suggest genetic and sweat tests for cystic fibrosis if you have inflamed pancreas (pancreatitis), nasal polyps, chronic sinus or lung infections, bronchiectasis, or male infertility.