 Gene therapy is a technique used to correct defective genes responsible for disease development.  There are several techniques to do this:  Normal gene inserted into nonspecific area of genome to replace non-functional gene (most common).  The gene is swapped through homologous recombination.  Repair the abnormal gene through selective reverse mutation, returning it to normal.  Alter the regulation (degree of which the gene is turned on and off) of a particular gene.

 A carrier molecule called a vector is used to carry the desired gene to the target cells.  The most common vector is a virus  Scientists remove the disease-causing gene and insert the desired one.  One problem scientists have with this is removing the disease-causing gene without taking away its ability to insert the DNA into target cells.  Some of the types of viruses used: retroviruses, adenoviruses, adeno-associated viruses and herpes simplex viruses.

 There are nonviral methods of inserting the gene, the simplest being direct insertion of the gene into the cell. This method is limited to certain tissues and requires large amounts of DNA.  Another nonviral approach is creating an artificial lipid sphere with an aqueous core, which is capable of passing the DNA through the cell’s membrane.

 There are two types of gene therapy.  Germ line therapy: is replacing the defective genes in sperm or egg cells with a proper functioning gene. This change would be passed on to later generations, effectively eliminating the genetic disorder or hereditary disease from that family line.  Somatic therapy: the genes are replaced in the somatic cells (every other kind of cell except sperm and egg) of the patient. This limits the fix to that individual person and will not be inherited by later generations.

 Short-lived nature: The therapeutic DNA in the cells must remain functional and the cells themselves must be long-lived and stable for gene therapy to become a permanent cure. The rapid dividing nature of many cells prevents any long- term benefits. Patients will have to undergo multiple sessions of therapy.  Immune response: our immune system is designed to attack any foreign objects that enter the body. Their is a risk that the immune system will react to the virus used to carry the gene, reducing the effectiveness of gene therapy. Furthermore, the immune systems ability to remember invaders makes it difficult for repeat therapy.

 Viral vectors: scientists are afraid that when the virus containing the therapeutic DNA enters the body it may recover its ability to cause disease.

 February 2005: deafness is ‘cured’ in guinea pigs. Inner-ear hair cells were destroyed. Injected Atoh1 gene into cells in inner ear. Brought back 50%-80% of original hearing.  April 2008: UK researchers perform first clinical trial for rare inherited blindness. Trial showed treatment is safe and can improve sight.  March 2009: gene wrapped in nanoparticles used to target and destroy hard-to-reach cancer cells in mice. Hope to have human testing within 2 years.

 They are hoping in the future all hereditary diseases and genetic disorders will be eliminated with germ line therapy.  The next step would be sending in genes that depict the child’s eye or hair colour. Being able to come up with a program to ‘design’ your baby to your liking.  Then taking it one step further and sending in genes to improve this like the child’s physical strength and brain power. To create a ‘superhuman’.

 We are altering what god intended for us.  The cost of germ line therapy will be so high only upper class families can afford it.  Could the widespread use of gene therapy make society less accepting of people who are different.  Should people be able to use gene therapy the enhance human traits such as athletic ability.

We must be careful or We Will Suffer The Ultimate Consequence!

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