Gene therapy: a brief review.

Gene therapy is no longer defined simply as gene replacement; today, it is better defined as any treatment involving genetic alteration of cells. As a result, its applications have grown enormously and continue to do so. The purpose of gene therapy--treatment of the underlying cause of disease--represents a fundamental break with all previous forms of therapy in the history of medicine. Within a relatively short period, gene therapy promises to be a major pharmacologic force, revolutionizing the practice of medicine.