Gene Therapy By: Ashley Hale & Cody Stevens

What is gene therapy? Genes are specific sequences of bases that encode instructions on how to make proteins. These proteins perform most life functions and even make up the majority of cellular structures. When genes are altered these proteins cannot carry out their functions and genetic disorders can occur.

Types of gene therapy. There are two types of gene therapy: Somatic gene therapy – done in the adult cells of persons known to have the disease. Germline gene therapy – done in the sperm or the egg and prevents the trait from being passed on to further generations.

How does gene therapy work? Researchers use several different approaches for correcting faulty genes Some of these are: A normal gene may be inserted to replace a non-functional gene An abnormal gene could be swapped for normal gene through homologous recombination. The abnormal gene could be repaired through selective reverse mutation, which returns the gene to it’s normal function. The regulation of a particular gene could be altered.

The use of viruses for gene therapy A carrier molecule, called a vector, must be used to deliver the therapeutic gene to the patients cells. The most common vector is a virus that has been genetically altered to carry normal human DNA. Viruses have evolved a way of encapsulating and delivering their genes to human cells in a pathogenic manner. Some of these are: Retroviruses Adenoviruses Adeno-associated viruses Herpes simplex viruses.

What makes gene therapy an ineffective treatment? Short lived nature of gene therapy - problems with integrating therapeutic DNA into the genome and the rapidly dividing nature of many cells prevent gene therapy from achieving long term benefits. Immune response - when a foreign object is introduced into the body, the immune system attacks the invader making gene therapy dangerous for the patient. Problems with viral vectors – toxicity, immune and inflammatory responses, gene control, and targeting issues are problems that come with viral vectors. Multigene disorders – most commonly occurring disorders, such as heart disease and high blood pressure, are caused by combined effects of variations in many genes. Gene therapy is best in cases of mutation in just a single gene.

Is it ethical? Is gene therapy ethical? Here are some questions to consider: What is normal and what is a disability or disorder, and who decides? Are disabilities diseases and do they need to be cured or prevented? Does searching for a cure demean the lives of individuals affected by disabilities? Preliminary attempts at gene therapy are expensive. Who will have access to this type of therapy, and who will pay for their use?

The End 