Final answer:
Cystic fibrosis mostly affects the lungs, causing severe respiratory issues, despite also impacting other organs. It is caused by a defective CFTR gene, leading to chronic lung infections.
Step-by-step explanation:
Cystic fibrosis (CF) primarily affects the lungs in the body, leading to breathing difficulties and chronic lung infections. It is a genetic disease caused by a malfunctioning membrane ion channel called the cystic fibrosis transmembrane conductance regulator, or CFTR. While CF also impacts the liver, pancreas, and intestines, the greatest disability and premature death in people with CF stem from lung issues. Despite no known cure, advances in treatment have significantly extended the life expectancy of those with CF.