1. GENE THERAPY

2. What is gene therapy? Gene therapy is the introduction of normal genes into cells that contain defective genes

3. Why gene therapy? To supply the cells with the correct directions to make a missing protein product

4. How? 2 Delivery Systems 1. In vivo occurs within the organisms

5. 2. Ex vivo occurs outside the organism

6. Who? The First Case September 14 th, 1990 –Ashanti DeSilva was treated for SCID Sever combined immunodeficiency Gene is located on chromosome #22 –Doctors removed her white blood cells, inserted the missing gene into the WBC, and then put them back into her blood stream. –This strengthened her immune system –Only worked for a few months  Would this be considered in vivo or ex vivo?

7. Vectors Vectors are carriers. (ex. insects are considered vectors for pollen) Vectors transport the DNA into the body or into the cells. What was the vector in the transformation lab?

8. Viruses are frequently used as vectors because: They insert their viral DNA into cells as a normal part of their lifecycle. So, why not let the virus inject the good gene into a cell? Imagine this lifecycle taking place in the human body with a good gene. Explain what would happen?

9. General concerns The Food and Drug Administration (FDA) has not yet approved any human gene therapy product for sale. Major problems with gene therapy: 2) Immune response. It reduces gene therapy effectiveness and makes repetitive rounds of gene therapy useless 3) Viral vectors. Immune and inflammatory responses, also fears that viral vector may recover disease-causing ability 5) Target. One does not have control over where the gene will be inserted into the genome 1) Short-lived. Very hard to achieve any long-term benefits 4) Multigene disorders. Disorders such as heart disease, Alzheimer's disease, arthritis, and diabetes, are caused by the combined effects of many genes.

10. Now!! More than 5000 patients have been treated in last ~12 years worldwide

11. Progress Slowed In 1999, 18-year-old Jesse Gelsinger died from multiple organ failure 4 days after treatment for an enzyme deficiency. –Death was triggered by severe immune response to adenovirus vector January 2003, halt to using retrovirus vectors in blood stem cells because children developed leukemia-like condition after successful treatment for X-linked severe combined immunodeficiency disease (bubble boy disease)

12. Progress Continues Cystic Fibrosis Alzheimers Parkinsons Sickle Cell You will read more…….