What is Gene Therapy? Defective genes make non-functional proteins, creating genetic disorders Gene therapy corrects defective genes by inserting a functional gene somewhere into the affected chromosome Gene therapy can also repair bad RNA
How Gene Therapy Works Viruses are genetically altered to carry therapeutic human genes Virus is a “vector” for the good genes Virus infects target cell by injecting its DNA or RNA into cell’s genome Therapeutic genes are incorporated into target cell’s genome, and correct proteins are made
Uses for Gene Therapy Ex: Severe Combined Immune Deficiency (Bubble Boy) Syndrome - patients don’t make enzyme needed for immune system development - send therapeutic genes to bone marrow cells (make immune system cells) - bone marrow now can make immune cells, and boy no longer lives in bubble
Uses for Gene Therapy Huntington’s Disease: send in RNA that interferes with and destroys faulty RNA Hemophilia, Cystic Fibrosis, Thalassemia: substitute faulty mRNA with good mRNA Instead of fixing adults, we could do gene therapy on sperm, eggs, and embryos (designer babies!)
Problems with Gene Therapy Short term fix (must get continued viral injections) Immune system can respond to viral vector, killing patient Only fixes disorders caused by one gene- what about multi-gene disorders?
Current Status FDA has not approved use of gene therapy in U.S. Based on trial done in France that killed two boys, including David Vetter (bubble boy), in 1999 and 2003. Is the risk worth the lives that could be saved?