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Cystic Fibrosis

Cystic Fibrosis

Cystic Fibrosis

Description
 Cystic fibrosis is a life-long illness that is usually diagnosed in the first few years of life. It is an inherited disease that affects sodium channels in the body and causes respiratory and digestive problems. Cystic fibrosis affects the mucus and sweat glands of the body and is caused by a defective gene. Thick mucus is formed in the breathing passages of the lungs and this predisposes the person to chronic lung infections. It most commonly affects breathing and digestion. Advances in medical treatment continue to improve the outlook for affected children and adults. However, there is no cure. Most affected individuals survive to about age 30, though some die in childhood and others live to age 40 or beyond.

Who is at Risk?
 About one in 2500 Caucasians is affected, and 2 - 5% of Caucasians carry the cystic fibrosis gene. It is most common among Caucasians of Northern or Central European descent and is much less common in other ethnic groups. Risk factors include a family history of cystic fibrosis or unexplained infant death.

Sources: A.D.A.M., Inc., March of Dimes Birth Defects Foundation, The American College of Obstetricians and Gynecologists

A Fresh Look at Cystic Fibrosis
 Cystic fibrosis occurs because of mutations in a single human gene called CFTR. A paper in The Journal of Cell Biology from investigators at TSRI, led by Professor William Balch, Ph.D., presents a fresh view of how CFTR mutations lead to cystic fibrosis. When CFTR fails to perform its function, there is an imbalance in the movement of ions and water in and out of the tissue, and the body may lose the ability to regulate the consistency of mucus and other secretions. Because the small air sacs at the termini of the lung"s airways need to be bathed continuously in a glycoprotein bath, the lungs require CFTR chloride channels to function properly. In children with cystic fibrosis, defects in the CFTR gene lead to decreased amounts of CFTR proteins on the surface of the cells, and without the CFTR-mediated movement of ions and water, there is not enough water in their lung secretions to maintain their consistency.

Cystic fibrosis manifests as abnormally thick mucus in the lungs, leading to obstructed airways, chronic coughing, and bacterial infections. Over time, these symptoms can lead to chronic and progressive damage to the respiratory system and other organs. Currently, no FDA-approved treatments can correct the accumulation of abnormally thick mucus in the lungs or the underlying defect that leads to it. Hoping to improve this situation, Balch and his colleagues have engaged in a long course of study aimed at understanding the detailed molecular and cellular mechanisms involved in CFTR and cystic fibrosis. For the first time, they understand what it takes to get CFTR protein out of the endoplasmic reticulum, a folded system of membranes that loop back and forth giving the cytoplasm a very large surface area. The next step will be to identify where in the pathway the folding of CFTR is defective and to find ways of targeting the defect to correct it. That advance may lead to better medications to control cystic fibrosis.

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