Why there is still no cure for cystic fibrosis and explain the challenges for the development of effective treatments?

The genetic defect responsible for creating the symptoms associated with cystic fibrosis was first reported in 1989. Almost 32 years later, discuss why there is still no cure for this disease and explain the challenges for the development of effective treatments. Some reference from Google Scholar searched Journal Paper or Research Paper should provide experimental evidence and diagrams to help explanation. Referencing style: Harvard You should include some journal paper resources (2-4) search from Google Scholar. And may be some nice diagram also from some journal paper from Google Scholar.