Cystic fibrosis
Cystic Fibrosis is a genetic
disorder that affects the respiratory, digestive and reproductive systems
involving the production of abnormally thick mucus linings in the lungs and can
lead to fatal lung infections. The disease can also result in various
obstructions of the pancreas, hindering digestion. An individual must inherit
two defective cystic fibrosis genes, one from each parent, to have the disease.
Each time two carriers of the disease conceive, there is a 25 percent chance of
passing cystic fibrosis to their children ; a 50 percent chance that the child
will be a carrier of the cystic fibrosis gene; and a 25 percent chance that the
child will be a non-carrier.
Prevalence:
The incidence of CF varies
across the globe. Although it is severely underdiagnosed in Asia, existing
evidence indicates that the prevelance of CF is rare. In the European Union 1
in 2000-3000 new borns is found to be affected by CF . In the United States of
America the incidence of CF is reported to be 1 in every 3500 births.
Diagnosis/ prognosis:
People with CF have a variety
of symptoms including: very salty-tasting skin; persistent coughing, at times
with phlegm; wheezing or shortness of breath; an excessive appetite but poor
weight gain; and greasy, bulky stools. Symptoms vary from person to person, in
part, due to the more than 1,000 mutations of the CF gene, several of which
have been identified and sequenced by researchers.The sweat test is the
standard diagnostic test for CF. This simple and painless procedure measures
the amount of salt in the sweat. A high salt level indicates CF. Although the
results of this test are valid any time after a baby is 24 hours old,
collecting a large enough sweat sample from a baby younger than 3 or 4 weeks
old may be difficult. The sweat test can also confirm the diagnosis in older
children and adults. If pancreatic enzyme levels are reduced, an analysis of
the person's stool may reveal decreased or absent levels of the digestive
enzymes (trypsin and chymotrypsin) or high levels of fat. If insulin secretion
is reduced, blood sugar levels are high. Pulmonary function tests may show that
breathing is compromised. Also, a chest x-ray may suggest the diagnosis.
Relatives other than the parents of a child with cystic fibrosis may want to
know if they're likely to have children with the disease. Genetic testing on a
small blood sample can help determine who has a defective cystic fibrosis gene.
Unless both parents have at least one such gene, their children will not have
cystic fibrosis. If both parents carry a defective cystic fibrosis gene, each
pregnancy has a 25 percent chance of producing a child with cystic fibrosis.
During pregnancy, an accurate diagnosis of cystic fibrosis in the fetus is
usually possible.
The severity of cystic fibrosis
varies greatly from person to person regardless of age; the severity is
determined largely by how much the lungs are affected. However, deterioration
is inevitable, leading to debility and eventually death. Nonetheless, the
outlook has improved steadily over the past 25 years, mainly because treatments
can now postpone some of the changes that occur in the lungs. Half of the
people with cystic fibrosis live longer than 28 years. Long-term survival is
somewhat better in males, people who don't have pancreatic problems, and people
whose initial symptoms are restricted to the digestive system. Despite their
many problems, people with cystic fibrosis usually attend school or work until
shortly before death. Gene therapy holds great promise for treating cystic
fibrosis.
According to the CF
Foundation's National Patient Registry, the median age of survival for a person
with CF is currently 33.4 years. Only thirty years ago, a CF patient was not expected
to reach adulthood. Many people even live into their fifties and sixties.
As more advances have been made
in the treatment of CF, the number of adults with CF has steadily grown. Today,
nearly 40 percent of the CF population is age 18 and older. Adults, however,
may experience additional health challenges including CF-related diabetes and
osteoporosis. CF also can cause reproductive problems - more than 95 percent of
men with CF are sterile. But, with new technologies, some are becoming fathers.
Although many women with CF are able to conceive, limited lung function and
other health factors may make it difficult to carry a child to term.
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