by Kimberly Allen, RN
The idea of gene therapy was first conceived in 1972. However, it wasn’t until 1990 that the first FDA approved gene therapy study occurred in the US. In the time since then, there have been more than 1,700 clinical trials conducted using a variety of techniques of administration in an attempt to treat a variety of serious diseases.
Genes are the basic building block of both your physical and functional units of heredity. they are carried on chromosomes in specific sequences that provide the information on instructions on how each cell is to make the proteins specific to that cell. It is these proteins that are responsible for building the majority of your cellular structure as well as perform most of the everyday functions in your life. It is when these genes become mutated so that the proteins can not perform their normal function that genetic disorders can occur.
Gene therapy is a treatment that involves using DNA as a pharmaceutical agent in the treatment of disease. Researchers believe and studies have shown that DNA can be used to either alter or supplement genes found with in the cells as a method of treating disease. There are a variety of ways that have been developed for gene therapy, the most common being the use of DNA from a functional, therapeutic gene to replace the non-functional one. There are other methods including the use of DNA that instead of being from a natural human gene is from a therapeutic drug. In this method the DNA from the therapeutic protein must be contained in a special molecule used to transport the genetic material into another cell. This special molecule is known as a vector. Another method being studied is to directly correct the mutated gene. Some researchers have studied swapping the abnormal gene for a normal gene through a genetic recombination process known as homologous recombination. Studies involving a process known as selective reverse mutation to repair a mutated gene and return it to it’s normal function as well as studies that involve turning genes on and off to change its function. The most common molecules or vectors used to transport the therapeutic genes into your cell with the abnormal gene is a virus. There are several different types of viruses that are used as vectors. Retroviruses are a type of virus that are able to create double stranded DNA copies of its RNA genomes that can be combined with the chromosomes of the host cell. The adenovirus which causes the common cold as well as other infections in humans also have double stranded DNA genomes and can be used as vectors. the adeno-associated virus is a single stranded DNA genome that is able to insert its genetic material on chromosome 19 at a specific location. The herpes simplex virus known for causing cold sores is another type of double stranded DNA that can be used as a vector for certain neuron cells.
Though there were many clinical failures early in its conception gene therapy has had several clinical successes since 2013 that have created new optimism in the future of gene therapy as promising treatment for numerous diseases including certain leukemia’s, Parkinson’s disease and certain muscular dystrophy’s. In 2012 the gene therapy known as Glybera was approved by the European Commission and became the first gene therapy approved for use in either the US or Europe. This type of gene therapy is used to treat lipoprotein lipase deficiency which is a rare genetic metabolic disease that leads to severe pancreatitis that can be fatal. What has made this form of gene therapy different from others is that researchers were able to modify an adeno-associated virus known as AAV-LPL 5447X so that it can not combine its own DNA into the host cell genome. It requires a particular protein to accomplish that which has been removed. This prevents the vector from causing other complications ranging from infections to cancer.
Gene therapy shows great promise for people suffering from genetic disorders that currently have no other effective treatments. Although there are no currently available gene therapies in the US there are numerous clinical trials throughout the US. these trials are for a variety of genetic disorders as well as certain cancers. The early results of some of these studies have given hope to the many people currently suffering from an incurable illness.
Kimberly Allen is a registered nurse with an AND in nursing. She has worked in ACF, LCF and psychiatric facilities, although she spent most of her career as a home health expert. She is now a regular contributor to HealthAndFitnessTalk.com, dispensing advice and knowledge about medical issues and questions. You can reach her with any comments or questions at firstname.lastname@example.org.