Gene therapy is a novel approach to treat, cure, or ultimately prevent disease by changing the expression of a person’s genes. Gene therapy is in its infancy, and current therapies are primarily experimental, with most human clinical trials still in the research stages.urrent and possible candidates for gene therapy include cancer, AIDS, cystic fibrosis, Parkinson’s and Alzheimer’s diseases, amyotrophic lateral sclerosis (Lou Gehrig's disease), cardiovascular disease and arthritis. In cases such as cystic fibrosis or hemophilia, disease results from a mutation in a single gene.