F Cystic fibrosis
Incidence and prevalence
Cystic fibrosis affects an estimated 30,000 persons in the United States, with 1000 new cases per year. Most are diagnosed between the ages of 3 months and 6 years, but 8% are not diagnosed until after 18 years. One in 31 Americans is an asymptomatic carrier of the defective gene. More than 80% of those born with cystic fibrosis are born to parents with no history of the disease.
Pathophysiology
Cystic fibrosis is caused by a mutation of a gene on chromosome 7. The result is defective chloride ion transport in epithelial cells in the lungs, pancreas, liver, gastrointestinal tract, and reproductive organs. This decrease in chloride transport results in a decrease of sodium and water transport. This results in dehydrated, viscous secretions that can cause obstruction, destruction, and scarring of exocrine glands.