Gene Therapy - The Biological Basis Of Gene Therapy, Viral Vectors, The History Of Gene Therapy, Diseases Targeted For Treatment By Gene Therapy

Gene therapy is a rapidly growing field of medicine in which genes are introduced into the body to treat diseases.

Gene therapy is the name applied to the treatment of inherited diseases by corrective genetic engineering of the dysfunctional genes. It is part of a broader field called genetic medicine, which involves the screening, diagnosis, prevention and treatment of hereditary conditions in humans. The results of genetic screening can pinpoint a potential problem to which gene therapy can sometimes offer a solution.

Genes represent the genetic material that organisms pass on from one generation to the next. Therefore, genes are responsible for controlling hereditary traits and provide the basic biological code or blueprint for living organisms. Genes produce protein such as hair and skin as well as proteins that are important for the proper functioning of organs. Mutated or defective genes often cause disease. The purpose of gene therapy is to replace a defective gene with a normal copy of the same gene in attempt to restore function. Somatic gene therapy introduces a normal gene into tissues or cells to treat an individual that has an abnormal gene. Germline gene therapy inserts genes into reproductive cells (the egg or the sperm) or into embryos to correct genetic defects that could be passed on to future generations. Germline gene therapy differs from somatic gene therapy in that germline integration of a gene will ideally correct every progenitor cell that differentiates from the germ cell. Somatic gene therapy involves integrating corrected genes into cell and tissues that are fully differentiated or mature.

Initially conceived as an approach for treating inherited diseases, like cystic fibrosis and Huntington's disease, the scope of potential gene therapies has grown to include treatments for cancers, arthritis, and infectious diseases. Although gene therapy testing in humans has rapidly advanced, in general, the field of gene therapy has proven to be problematic and complicated by a variety of ethical issues. For example, some scientists are concerned that the integrating genes into the human genome may cause disease. There has been evidence that randomly integrating corrected genes might disrupt other genes in the genome and if the disrupted gene is a tumor suppressor gene, cancer may develop. Others fear that germ-line gene therapy may be used to control human development in ways not connected with disease, like intelligence or appearance.