Viral gene therapy is the use of viruses to deliver healthy genetic material to cells that have a damaged or defective section of deoxyribonucleic acid (DNA). In 2011, the science is still in its infancy, though many doctors and scientists are hopeful that it could one day be used to cure various diseases at the source of the problem. By correcting the DNA itself, a viral gene therapy works by correcting faulty code instead of by alleviating symptoms or by strengthening the immune system.
Genetic disorders are caused by faulty sections of genetic code. The faulty code, which is used to synthesize proteins that the body uses for many different functions, creates proteins that cannot do their job correctly. There are a few different ways that viral gene therapy can be used to correct a faulty section of DNA.
The most common use for viral gene therapy is to insert healthy genes into a strand of DNA. While this does not remove the section of code that causes the problem, the normal gene overrides its abnormal counterpart, correcting the problem. Conversely, abnormal genes can be corrected through the use of genetic mutation. Abnormal genes can also be replaced with functional versions of the gene.
In any of these cases, it is necessary to use a gene therapy vector that can transfer the functional gene to the DNA. Though there are a number of different types of vectors, the most common are viruses. These viruses are modified versions of common viruses that attack human cells, such as herpes or the viruses that cause colds. Using viral gene therapy does not pose a risk to the patient because the genetic material in the viruses has been removed and replaced with healthy genes from the human genome. Different viruses are drawn to different types of cells, which they invade, as normal viruses might, releasing healthy human genes into the cells instead of viral genetic material.
Though viral gene therapy has promise as a new type of medicine, it is still in its infancy. There are currently no medical treatments that rely on viral gene therapy that have been approved by the United States Food and Drug Administration. Studies in viral gene therapy have not proven to be particularly effective, and further experimentation and development is necessary before the procedure will benefit human patients.