Cystic fibrosis (CF), also called mucoviscidosis, is an autosomal recessive hereditary disease of the exocrine glands. It affects the lungs, sweat glands and the digestive system. It causes chronic respiratory and digestive problems. more...
The first manifestation of CF is sometimes meconium ileus, occuring in 16% of infants who develop CF.
Other symptoms of CF usually develop during early childhood. Both lungs and pancreas produce abnormally viscous mucus. This mucus begins to build up and starts to clog the opening to the pancreas and the lungs. The mucus in the lungs can become a growth medium for bacteria, resulting in chronic respiratory infections and eventual permanent damage to the lung tissue. A chronic and loose sounding cough is common in people with CF. These thick secretions also obstruct the pancreas, preventing digestive enzymes from reaching the intestines to help break down and absorb food. Frequent and foul smelling stools are often an early sign of CF along with fatty oil that is visible in the stool. This can compromise growth and overall nutrition if proper treatment to aid digestion is not utilized early in life. As lung function deteriorates, CF patients can develop pulmonary hypertension and eventually cor pulmonale. Death usually occurs from severe infection, pneumonia, or heart failure.
The disease can be diagnosed by symptoms such as a high salt concentration in a baby's sweat (via sweat test) or by genetic testing. Prior to genetic testing, a sweat test was the gold standard for diagnosis of CF. The disease can also be diagnosed prenatally through chorionic villus sampling or amniocentesis.
History and statistics
Cystic fibrosis was first described as a disease in the late 1930s by Dorothy Hansine Andersen. It is the most common genetic disease among people with European ancestry. Approximately one in every 25 people of European descent is a carrier of one of the cystic fibrosis mutations, having one normal gene and one CF gene. Since cystic fibrosis is recessive, both copies of the gene have to be CF genes to cause the symptoms that occur in about 1 in every 2500 children. The high incidence of this lethal gene can be explained by the fact that CF carriers, who don't show any symptoms, enjoy some protection against cholera, since the extreme water loss in the intestines is prevented. More recently, evidence suggests CF genes could give protection against typhoid fever. People from areas where cholera and typhoid fever are not problems show a much lower incidence of CF. Genetic counseling and genetic testing is recommended for families who may be carriers of cystic fibrosis.
In 1988, the first mutation for CF, ΔF508, was discovered by Francis Collins, Lap-Chee Tsui and John R. Riordan on the seventh chromosome of the human genome. Research has subsequently found over 1000 different mutations that may cause CF, however ΔF508 accounts for approximately 70% of CF patients in Europe (this percentage varies regionally).
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