Gene Therapy: The Future of Medicine

All lifeforms are made with the use of genes. These genes, stored on molecules called Deoxyribose Nucleic Acid (DNA), contain information which the cells use to manufacture proteins which are used to create, among other things, new cells. DNA can be thought of as the blueprint of your body, the template which was used to create you and all the different types of tissue inside of you. With the discovery of DNA came a more fundamental understanding of life as we know it, as well as many new techniques for identifying and treating certain illnesses.

A genetic disorder occurs when there is a defect in one’s genome which prevents one or more biological processes from naturally occurring. Genetic disorders can be inherited from one’s parents, or they can occur due to a mutation (sudden change in one’s genome due to external factors) occurring during one’s conception or gestation. Genetic disorders can cause a wide variety of chronic health issues for the patient, which can be relatively benign (like Alkaptonuria, which prevents the metabolism of the amino acids phenylalanine and tyrosine), to severely crippling (like hemophilia, which prevents blood clotting and makes it difficult for wounds to heal). Other genetic factors, while not directly causing disease, have been linked to higher rates of cancer and other diseases. Because these disorders stem from flaws in the genome, they cannot be cured. Unless, that is, a change is made to the genome.

Gene therapy is a clinical procedure where a corrected copy of a missing or otherwise nonfunctional gene is placed into a patient’s genome through a vector. That vector is typically a virus, which is able to naturally alter the genome of cells as a part of its reproductive process. As gene therapy is relatively new, its current applications are limited. As of the time of writing this article, candidates for gene therapy are those whose genetic disorder stems from a flaw in a single gene, which create disorders whose biology (type of tissue affected, how the tissue is affected, etc.) is well-understood.

Gene therapy works by first identifying the gene causing the targeted genetic disorder. Once the flawed gene is determined, a corrected copy of the gene is synthesized. This corrected copy is then inserted into a selected virus. The virus is then incubated with stem cells derived from the patient. The virus, as it multiplies, will insert the corrected gene into the stem cells, overriding the flawed gene and thus eliminating the genetic disorder in those cells. Once it is determined that the stem cells have successfully received the corrected gene, the stem cells are then transplanted back into the patient’s body, where they regenerate as functional tissue which is able to perform whatever function the genetic disorder was preventing. This technique has been used in trials to treat multiple genetic disorders, including certain immune deficiencies, hereditary blindness, and hemophilia.

Gene therapy has also been used to treat non-genetic disorders. For instance, one series of trials used a virus to genetically modify a patient’s white blood cells so that they would be able to recognize a protein found on cancer cells. When these modified blood cells were transplanted into 59 patients with leukemia, 26 experienced complete remission.

While still in its early stages, gene therapy has shown great promise in treating genetic disorders, and may even be used to treat other diseases. With the use of viral vectors, it is not only possible to correct certain genetic defects in targeted tissue, but it is even possible to enhance said tissue so that it can better fight other diseases. As this technology becomes more sophisticated, diseases which were once deadly may soon be treatable, if not curable.  

References:

Table of Genetic Disorders. www.kumc.edu/AMA-MSS/Study/table_of_genetic_disorders.htm.

What is Gene Therapy?. Nutrition & the Epigenome, www.learn.genetics.utah.edu/content/genetherapy/intro/.

Genetic Therapy Successes. Nutrition & the Epigenome, www.learn.genetics.utah.edu/content/genetherapy/intro/.