Gene Therapy

1. Gene Therapy Jordan Jones Lauren Johnson

2. What is it? • Gene therapy, also known as genetic modification, is a technique for correcting faulty genes that are responsible for developing diseases.

3. Why do it? • Gene therapy is a form of treatment intended to improve or cure a person of an otherwise untreatable genetic abnormality that could hinder your lifestyle or shorten his/her lifespan.

4. How do they do it? • Scientists have found a way to alter viruses in a way that allows them to carry normal genes into the genome to replace faulty genes in a therapeutic manner. They call these enhanced viruses “vectors”.

6. Types • Somatic gene therapy – modifying the genetic make-up of some of the cells or tissues of the person being treated. This will only affect the patient, not his/her offspring. • Human Germline Genetic Modification (HGGM) – modifying the patient’s sperm or egg cells so that the modification will alter the genetic make-up of future generations.

7. Techniques • The most common approach is to insert a normal gene into a nonspecific location in the genome to replace the nonfunctional one. • A nonfunctional gene can be swapped for a normal one through homologous recombination. • The nonfunctional gene can be repaired with selective reverse mutation which returns a gene to its normal function. • Altering the regulation of a gene. (Changing the degree to which it is turned on or off)

8. Why isn’t it more popular? • Short-lived effects – Due to most cells short life span and rapid division, it is difficult to maintain the intended effect of the therapy. Multiple rounds of gene therapy would be necessary. • Immune response – Whenever a foreign substance is introduced into the body and the immune system does not recognize it as your own, it fights back. This means that the therapeutic gene would be attacked and killed before it could take effect.

9. Popularity, cont’d… • Problems with viral vectors – Since the vessel of choice is a virus it is a possibility that the virus could regain its normal ability to cause disease. • Multigene disorders – Most common genetic diseases occur from a combination of defective genes. With gene therapy, the operative candidates for treatment are single-gene disorders because current techniques are only able to target one gene at a time.