cystic fibrosis

Question

Why is it that one can not cure cystic fibrosis?

Answer

Dear ECORN user,
This is indeed an important question. The simple answer is that cystic fibrosis is caused by a change in the genes. To truly cure CF one should thus alter the genes. Unfortunately gene therapy is at present not available.
First some general information. The code necessary to make all proteins that our body needs to function normally is stored in the genetic material in every cell of our body, on the genes on the chromosomes. Genes are translated to proteins by special machinery in the cell. Every protein has a specific function in the cell. An error in the code of the genes on the chromosomes will thus lead to poor or no function of a specific protein. We thus speak of an inherited disorder since this person can also transmit this error in his genes to his descendants.

Cystic fibrosis is an inherited disease and is caused by an error in the CFTR gene, the gene for cystic fibrosis on chromosome number 7. The normal CFTR gene will lead to the formation of a normal CFTR protein. This CFTR protein functions as a channel for the transport of chloride (the negative part of salt) and is necessary for the normal function of the cells including the cells lining the lung surface. An error in the CFTR gene will lead to the formation of an abnormal CFTR protein. Patients with CF have insufficient chloride transport out of the cell and an exaggerated uptake of sodium (the positive part of salt) into the cell. Together with sodium, water is drawn into the cells and the fluid lining the cell surface is dried out. This explains the sticky secretions in the airways that block the airway and cause infection. The treatment of CF is thus medicines that make the secretions more fluid, lots of chest physiotherapy to clear the sticky secretions and antibiotics to combat the infection This treatment is important and improves survival and quality of life in CF patients. But that is not the same thing as curing the disease or restoring the error in the CFTR gene.

Up till now – unless in the experimental stadium – there is no efficient method to cure a mistake in the genes. We do however get more view on treatments that change the basic defect in cystic fibrosis by restoring the defective protein. The abnormal chain of events is abnormal gene – abnormal protein – dried out mucus. The higher we intervene in this chain of events, the closer we come to curing the disease. Drugs such as PTC124 and VX770 are designed for CF patients, carrying specific mutations. They aim at restoring the defective protein and at improving the transport of salt and water in the airway epithelium. With these types of treatment we come closer to curing cystic fibrosis. Type these medicine names in on Google and you will get a lot of interesting information.
Yours sincerely,
Prof. Kris De Boeck

26.01.2009