Understanding the Basics of Gene Therapy
What is Gene Therapy?
Gene therapy is the introduction, removal, and replacement of genetic materials for the treatment of diseases. The genetic materials are specifically DNA (deoxyribonucleic acid) and RNA (Ribonucleic acid) because they make up these genes. Gene therapy uses these genetic materials to repair faulty genes and treat specific genetic diseases by replacing, altering, or supplementing a gene that is absent or abnormal and whose absence or abnormality is responsible for the disease. Gene therapy may use these genetic materials as a means of treatment (Hetch).
You cannot fully understand gene therapy without having basic knowledge about the genetic makeup of the human body. Through this article, you will understand the basics of gene therapy, what the genetic materials are that make up a human, and how these materials play a major role in gene therapy.
What is a Gene?
A gene is a unit of heredity. Genes are made up of DNA, which are the blueprints made up of proteins and enzymes used to build up the body. Humans have between 20,000 to 25,000 genes, with two copies of each gene inherent from the parents, with each being held to determine some characteristic of an offspring.
Sometimes these genes are not built up correctly. A small adjustment in the DNA can affect the protein makeup, which in turn affects the makeup of an organism. The absence or abnormality of a specific gene is responsible for specific diseases.
“Genes mutate all the time as a result of chemical processes in the cell, external influence, U.V lights, and so on. These mutants are what cause genetic diseases.”
— Dr. Michele Calos, Ph.D. Professor, Department of Genetics. ASGCT president (2018 -2019)
Changes in a gene, known as a mutation, directly result in genetic disorders. Conditions such as cystic fibrosis, hemophilia, vitiligo, etc, are a result of these genetic mutations. Environmental factors can interact to cause other conditions such as high cholesterol and high blood pressure. Disorders associated with aging often involve the loss of gene activity in specific types of cells. Some infections may also be related to gene defects. They have two sets of genetic determinants: the genes of the infective agent and the genes of the person with the infection (Hetch).
Gene therapy is applied due to these mutations to treat these mutations, by transferring or replacing the correct gene with the faulty gene in the affected genetic material. Below are lists of things that could be achieved using gene therapy:
Changes in how a protein or group of proteins is produced by the cell.
Increasing the levels of disease-fighting proteins
Introducing newly modified proteins into the cell.
How The Genetic Materials Are Delivered Into The Cell During Gene Therapy
Naturally, a gene cannot be inserted directly into a cell. A carrier known as a vector is used in such a case to deliver the relevant genes to the specific point needed. Typically, viruses, with the infectious part already removed through a form of genetic engineering, are used as a vector to insert the gene into the cell. Such viruses are called viral vectors or carriers because they take total advantage of the natural ability of a virus to enter a cell and deliver genetic material to the nucleus of the cell that contains its DNA. This makes it harmless when it is inserted into the nucleus (where the genetic materials- DNA and RNA are found) of the cell.
Kinds of Gene Therapy
The two kinds of Gene Therapy are:
In vivo gene therapy
Ex vivo gene therapy
In in-vivo gene therapy, the new genes are directly introduced into the patient's cells while the cells are still in the patient's body.
In ex vivo gene therapy, "gene delivery can be used in cells that have been removed from the patient's body". The cells are extracted from the human body, then the genes are added to the cells in the laboratory to be worked on before they are inserted back into the patient’s cell in the body.
The right approach depends on the disease infecting the patient and the infected tissues. These would give an idea of the best approach to apply gene therapy. The selection of a delivery approach also depends on the target cell, the duration of gene expression required for therapeutic effect, and the size of the piece of DNA to be used during the process of gene therapy.
Benefits Of Gene Therapy
In summary, the benefits of gene therapy include, but may not be limited to:
Being used to replace missing or defective genes.
Delivery of genes into the cell to treat genetic diseases genes that cause cancer cells to revert to normal cells could be supplied through gene therapy.
Bacterial or viral genes delivered through gene therapy may be used as a form of vaccination
Promotion or impediment in the growth of new tissue such as tumors, as well as potentially stimulating the healing of damaged tissues.
In the near future, advancement in gene therapy research will allow us to more effectively treat and hopefully avoid genetic diseases. A large variety of genes are now being tested for use in gene therapy. For example, mutations in the human CD117 gene caused Piebaldism, a rare autosomal dominant disorder of melanogenesis that is characterized by depigmentation of skin patches. Therefore, CD117 is considered to be a candidate gene for vitiligo. It is not yet proven, but this mutated CD117 gene could be removed and replaced with an effective gene. In time to come, gene therapy would be easily practiced and used to cure genetic and autoimmune diseases.
Work Cited
Al-Shobaili H. A. (2011). Update on the genetics characterization of vitiligo. International journal of health sciences, 5(2), 167–179.
Frederick Hetch, MD, FAAP, FACMG: Gene Therapy- The Future is Here. Medical Author (from the archives). Available from https://www.medicinenet.com/gene_therapy_-_the_future_is_here/views.htm
Hemdifferently: A deeper dive into the method of gene transfer research. Available from https://www.hemdifferently.com/steps-of-gene-transfer-therapy/#:~:text=A%20deeper%20dive%20into%20the,can%20produce%20a%20needed%20protein.
