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Gene Therapy

Gene Therapy. Meredith Calhoun. What is Gene Therapy?. - Gene therapy is a form of treatment that changes defective genes to stop a disease. - Gene therapy can be used instead of medicines or surgery. - It uses viruses to genetically modify a cells DNA. How does it work?.

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Gene Therapy

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  1. Gene Therapy • Meredith Calhoun

  2. What is Gene Therapy? - Gene therapy is a form of treatment that changes defective genes to stop a disease. - Gene therapy can be used instead of medicines or surgery. - It uses viruses to genetically modify a cells DNA.

  3. How does it work? • In gene therapy, researchers use viruses to correct the genes in cells by injecting desired genetic material in to the virus. MANY viruses are then put in the body to deliver the correct gene to the cells or take the cells out and let the DNA be corrected. Then corrected cells are put back into the body. These viruses have been genetically engineered so that they can't reproduce. Scientists are researching other ways to accomplish gene therapy. They are looking at a fatty molecule known as a liposome and physically inserting genes into the cell through "gene guns" or micropipettes.

  4. Steps: • 1. Diagnose disease or disorder and then find the gene that causes the disorder. • 2. Engineer virus and insert desired genes. • 3. Inject viruses into body (Vivo) or remove target cells for the disease (Ex Vivo). • 4. Allow viruses to inject genes into cells DNA to fix disorder. • 5. If target cells were removed and placed in culture with the viruses, then the corrected cells will be placed back in the body. Adenovirus

  5. Two types: • Somatic cell gene therapy- is gene therapy, or changing genes to fix a disease, in normal body cells. • This can fix the disease and cause the correct protein to be made, but the gene will not be passed on to your offspring. • Germline Therapy- is just replacing genes in reproductive cells • Because genes are changed in reproductive cells the new gene can be passed on to the offspring. • Affects many generation's DNA make up. The child will have the correct gene instead of the defected one.

  6. History • The 1960's and 1970's was when the idea of gene therapy first arose. • By 1972, Theodore Friedman and Richard Roblin published a paper explaining Stanfield Rogers gene therapy idea for curing humans with diseases. • In 1985 Dr.s W. French Anderson and Michael Blaese from the National Heart, Lung, and Blood Institute and the National Cancer Institute worked together to find that they could cure people,with Adenosine Deaminase Deficiency (ADA), using gene therapy. They conducted the first gene therapy in ADA cells in a tissue culture.

  7. History Continued • In 1986 Anderson and Blaese transferred correct genes into bone marrow of animals. • In 1988 they found gene therapy was more successful in white blood cells. • In 1989 Anderson and Blaese teamed up with Dr. Steven Rosenberg to see if gene therapy would be successful in patients with cancer, particularly melanoma.

  8. In the 1990's the first condition in humans was treated with Gene Therapy by Dr.s W. French Anderson and Michael Blaese. Two little girls, a four and nine year old, with an immune deficiency called ADA were cured through gene therapy.

  9. The Pros

  10. Obviously it's a positive that gene therapy can eliminate disorders before they begin or get to bad. • It can guarantee a cure for future suffering of some diseases. • Gene Therapy is considered a "medicine for the future" because it can control or alter Germ cells. Resulting in cured hereditary diseases and changing DNA for future generations. • Possibilities are endless. Since gene therapy is such a new technology, researchers are still finding gene therapy can cure many diseases. • Can possibly cure cancer, heart and lung disease, muscular dystrophy, blindness, AIDS, or even Alzheimer's.

  11. The Cons • With all new technologies there are possible consequences.

  12. Before gene therapy begins,your immune system must be weakened, so that the viruses can correctly inject the gene. The immune system can't tell the difference between a bad virus and a helping virus. • Since it is so new, it can be very expensive. • It's a new technology so not much is known about it. There could be consequences we don't know about yet. • The virus may change DNA in cells that don't need fixings or insert genes into the wrong part of the genome, this can lead to more serious problems such as cancer.

  13. Ethical and Religious Considerations • The first ethical issue is, Gene Therapy would put human fate in our hands by giving us the ability to affect genes of future generations. • Some are concerned it could give people the ability to make a superior race(eugenics), however this is not the goal of geneticists. • Some predict it would be hard to reinforce laws on gene therapy. And it could be offered on the black market. • Religion also plays a large role in an individual's considerations, some consider gene therapy is sinful. People believed gene therapy would be like "playing God".

  14. Current Applications • Gene therapy can be used to correct single gene mutation diseases like: • Cystic Fibrosis • Sickle Cell Anemia • Hemophilia has been treated in the U.S. Corrected the gene that allows the blood to correctly clot. • X-SCID is a immune deficiency where people lack B and T cells. Gene therapy corrects mutation on the X-gene and this causes the cells to be produced. • Type I Diabetes has been corrected in rats and dogs. • Paget's Diseases is a rare bone metabolism disorder caused by a gene being missing.

  15. Current Applications Continued • Chronic Granulomatus Disorder (CDG) has been cured in two patients. This disorder causes people to not be able to fight off bacterial and fungal infections. • Some cancer cells have been cured in a lab with many different types of gene therapy. • Neurodegenerative diseases like Parkinson's and Huntington's Disease have been cured in animals through gene therapy. • Diseases that are caused by more then one gene are being researched but are not yet used because of how complex it is to correct more than one gene at a time.

  16. Case Study • Using Gene Therapy to reverse blindness in dogs.

  17. Curing Blindness in Dogs • University of Pennsylvania researchers led scientists in using gene therapy to cure three puppies that were born blind. • The dogs in this experiment had a disease known as Leber Congenital Amaurosis (LCA). • The gene that is mutated stops making proteins that allow normal vision. • Retinitis Pigmentosa GTPase Regulator (RPGR) is the gene that contains the error. • The protein that can't be produced is photoreceptor ciliary. • The retina deteriorates and becomes dysfunctional when the dog has LCA.

  18. Curing Blindness Continued • A few weeks after the new genes were injected into a retina of one eye in each puppy, they began to gain vision. They could see and interact with humans and began to maneuver around objects. • A month after the genes had been injected into the retina, the scientists began testing the activity of each eye (with or without the corrected genes). • They used a technique called electro retinography, it measures the levels of electrical activity in the retina. • At the two month mark there was a 35%-40% electrical activity occurring in the retina that received gene therapy. The eye that didn't receive gene therapy had little to no activity.

  19. Since LCA occurs in humans, scientists are now researching to see if the gene therapy used on the puppies would still be successful on humans.

  20. Resources • • • • • • •

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