Drug for a genetic disease - more and more are sure to come.

Cystic fibrosis causes the body to produce an unusually thick, sticky mucus that clogs the lungs and obstructs the pancreas and stops enzymes from helping the body break down and absorb food. These patients are prone to infections and progressively lose the ability to breathe. The disease is caused by genetic mutations in a gene called cystic fibrosis transmembrane conductance regulator (CFTR) which regulates the transport of chloride and water in the body. The US Food and Drug Administration has approved "the first therapy to treat an underlying cause of cystic fibrosis”. The drug targets the most common mutation in the gene and restores the function (of CFTR protein) and not the symptoms of it. Approximately 4% of cystic fibrosis patients can be benefitted from this expensive therapy costing $294,000 a year.