Gene Therapy

A diagram explaining Gene Therapy

Imagine the treatment of a cancer patient. It is typically a long string of doctors appointments, surgeries, and medications such as chemotherapy. But what if there was a way to treat cancer with a simple injection? It seems incredible, and yet this is the aim of a new type of medical treatment called gene therapy. Not only would gene therapy treat cancer, but it could also treat cystic fibrosis, familial hypercholesterolemia, HIV/AIDS, gaucher disease, hearing loss, and could allow patients with circulatory problems in the legs to avoid amputation.

So, how would this incredible process work? It would begin on a molecular level. All of the aforementioned diseases and complications are caused by imperfections and mutations of the DNA. These are obviously very hard to treat with medications, and are typically hereditary. They can affect almost any part of the DNA. It is clearly quite hard to change a gene that is written into each and every cell in the human body, and coming up for a cure for these diseases has always been quite daunting. This is where gene therapy comes in. Gene therapy is the use of genes as treatment or prevention for diseases.

Using genes as a treatment? As fantastical as it sounds, this is the reality of gene therapy.  A "normal" gene is put into the genome in place of an "abnormal" gene which causes a disease or disfunction. This is done with several different treatments which fall under two headings: Germ-line gene therapy and somatic gene therapy. Germ-line gene therapy is when genes are introduced into reproductive cells or into embryos, so that the child will not have genetic abnormalities. On the other hand, somatic gene therapy is when therapeutic genes are inserted into cells to replace the current DNA or to make a protein/substance that is not present or not working in the patient. Most current research is developing somatic gene therapy.

Somatic gene therapy usually works via a "vector". The vector delivers the new gene to the patients cells. These vectors are almost always a virus which has had the infectious DNA replaced with the proper gene. These are either a retrovirus (such as HIV, which works well in dividing cells), an Adenovirus (such as the common cold, which works well in non-dividing cells), an Adeno-associated virus (which inserts DNA at a specific singular site on chormosome 19) or Herpes simplex virus (typically causes cold sores). There are new ways of developing gene therapy, including introducing the DNA directly to the cells, creating an artificial lipid with a water-based core which can travel directly through a cell membrane to deliver the gene, chemically linking the DNA to a molecule that attaches to the cell receptors, or even adding a 47th chromosome, which would not affect the cell in any way other than changing the defective gene.

Like any advancement in science, there are some questions and possible complications that come up when discussing gene therapy. If we put aside the omnipresent issue of "playing god", there are still a few problems. The primary problem is the use of viruses. Many scientists and researchers fear that one of the viruses injected into the DNA will go awry. Instead of being completely removed, the original virus would still retain its own DNA and begin infecting people. Although this is a justified concern, I believe that the benefits far outweigh the risks. If the makers of the injections are thorough in their testing, the company can have a product that is both safe and infinitely helpful to the modern world.

Check out this game about gene therapy!

http://ghr.nlm.nih.gov/handbook/therapy/genetherapy

http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml

http://www.encyclopedia.com/topic/gene_therapy.aspx

http://autocww.colorado.edu/~toldy2/E64ContentFiles/VirusesMoneransAndProtists/RetrovirusB1.html