GENE THERAPY Gene therapy is used to treat diseases. It comes from advances in genetics, molecular biology, clinical medicine and human genomics. Gene therapy is when you add a gene into a cell. Then the virus has to be modified to have a non-harmful virus-derived vector. This vector is a type of vehicle that can be used to carry a gene to cure the disease. Gene therapy requires the use of tools.
The tools need to have a capacity to cross the cell membrane and sometimes even the cell nucleus to deliver a gene to cure the disease. Viruses have been evolving for hundreds of years but we think of them as something harmful. It has taken time for us to modify them so that not all of them are harmful. These good viruses are used in gene therapy, because they have the ability to enter cells. Some of these viruses are: Adenoviruses, picornaviruses, parvovirus, oncoretroviruses, and even lent viruses, such as HIV. But these viruses haven't got the same capacity, for example, Adenoviruses and picornaviruses don't integrate, this makes them bad candidates for the long-term expression of a gene (which is needed for gene therapy of life-threatening genetic disease), and parvovirus are too small to package a large gene.
Oncoretroviruses and lent viruses are both dangerous viruses. Another problem is the dosage of vector, too much of this can derive to an immunological problem and causes death. For more than 10 years, scientists have been working to find gene therapies for diseases such as cancer, arthritis, vascular disease and genetic disorders. But no one has discovered any methods for them yet.