What is Cystic Fibrosis
Cystic Fibrosis is an inherited disease, this means it caused by irregular genes and you are born with it. It also means that people carrying the gene (but not necessarily with Cystic Fibrosis) can pass it on to their children.
Cystic Fibrosis is caused by a defect in the CTFR gene, this controls the production of a protein that controls cell transport of chlorine ions. This disrupts the natural water potential and the mucas becomes thick, so the cillia can't move it and this can sometimes cause blockages.
Cystic Fibrosis doesn't only affect the lungs, it causes problems for the entire body, the bile duct may become blocked and lead to cirrhosis; enzymes from the pancreas are not secreted which causes incomplete digestion; and infertility in both men and women.
The basic principle of gene therapy is to give patients copies of the correct gene so they can make the protein by synthesis.
There are two vectors that could be used to transport the CTFR gene. A harmless virus shown on the left which will deposit the gene into cells as viruses naturally do. Or a liposome (see here) which would be inhaled and hopefully would pass the gene through the cells.
The problems with either of the methods of gene therapy are twofold. Firstly, it isn't permanent since epithelial cells for example have a short life and are constantly being renewed, so the treatment would have to be taken regularly and this would be expensive.
Also, since Cystic Fibrosis is a disease that affects the entire body; it isn't possible to treat everything and whilst the lungs may be temporarily cured, the pancreas still will not function properly and the sufferer will still need to take enzyme supplements.