Gene Therapy: The Discovery of a Millennium

By: Melody Hansford

It was the early autumn of 1990. A young child named Ashanthi DeSilva was brought to the NIH Clinic in Maryland to undergo the world’s first gene therapy trial. She was diagnosed with severe combined immunodeficiency (SCID), a rare disorder that triggered the immune cells in her body to attack healthy cells. These patients have extremely fragile and weak immune systems as the body is on a constant rampage against its own cells. SCID patients are often recommended to spend their lives in a germ-free plastic bubble to protect their weakened immune systems. This unique treatment is quite reminiscent of Randal Kleiser’s famed 1976 drama, The Boy in the Plastic Bubble.

Dr. French Anderson, a geneticist at the NIH Clinic, proposed the insertion of a new functional gene into Ashanthi’s body, aiding her immune system to actively protect against authentic offending pathogens.

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Within two years of continued treatment, Ashanthi was attending school with other children, a life in a plastic bubble was now considered an absurd and laughable prospect.


DeSilva is just one patient of many that gene therapy has successfully treated. Hemophilia, cystic fibrosis, and Leukemia are but a few examples of the life-threatening diseases that gene therapy has been proven to treat and even cure.
Gene therapy, as a medical technique, has been in rapid development since 1990. This is partly due to the efforts of the Human Genome Project.

The Human Genome Project was incredibly influential to the science sphere as it was the first world sponsored program dedicated to researching the human genome. Countries from all over the world contributed to the project, and with combined effort, identified all the approximate 20,500 genes that exist within human DNA. Researchers attained another vital success as they identified the sequence and chemical pairings of all 3 billion bases that exist within DNA.


According to the National Human Genome Research Institute, “This ultimate product of the HGP has given the world a resource of detailed information about the structure, organization and function of the complete set of human genes. This information can be thought of as the basic set of inheritable "instructions" for the development and function of a human being.”

Genetic diseases are commonly caused by mutations to or deletions from the human genome. In the human body, each genetic instruction must be read and carried out exactly. One small mutation or misread of genetic information could lead to catastrophe. If one gene is “deleted” or not present in the human genome, birth and genetic defects are likely to arise.

 

Gene therapy can replace these mutations when they occur with a healthy, functional gene. When a new gene is implemented into a strand of DNA, that information is first taken by the RNA. The RNA delivers the new information to the ribosomes, where new healthy proteins are built. Once the proteins are produced, they should aid the body in carrying out correct genetic instructions.


Arthur Nienhuis, president of the American Society of Gene Therapy states simply, “Gene therapy is the addition of new genes to a patient's cells to replace missing or malfunctioning genes.”


Genetic editing techniques such as gene therapy have acted as a beacon of hope for patients with genetically caused disorders. Diseases that were once considered untreatable, are treated through the advances made every day in gene therapy.

Diseases that were once passed down from parent to child can now be eradicated. In certain types of genetic editing, faulty genes are replaced with healthy ones in patients with genetically associated diseases. As new healthy genes replace the malfunctioning ones, the disease will not be passed down from parent to child. Instead, the patient will pass on their new healthy genetic information to their children.


However, as the field of gene therapy develops and advances, the potential for adverse consequences becomes increasingly remote. Genetic editing is still considered a new and perilous procedure, as there is a large number of supposed risks involved.

As genetic information is carried into the body through a vector, which is typically a genetically engineered virus, the body may recognize the virus as a pathogen and attack it, causing inflammation and organ failure in severe cases.


Infection could arise in the body if the virus regains its ability to “cause disease”, according to the Mayo Clinic. Tumors may form and multiply throughout the body if new genetic information is inserted in the incorrect location in the DNA.


This potentiality opens an ethical Pandora’s box that patients, their families, and medical practitioners must contemplate together.


Many genetic diseases often have no cure or are difficult to treat with conventional medical techniques. Genes contain vital instructions within the body and are engrained into a person’s DNA. Limited knowledge concerning the treatment and development of genetic diseases contributed to the paralyzing effect on researchers' abilities to find a definitive cure. For this reason, the development of gene therapy was a welcomed breakthrough for the medical community.


At this time, genetic editing is the only medical technique in existence that can offer a permanent solution for genetically caused diseases, which is not possible with modern, conventional medicine.


Gene therapy, a new medical procedure, is often stigmatized by the public as a “last resort” treatment. Rather, this air of stigma and uncertainty will cease as gene therapy advances and more people are treated as a result of its development. Genetic editing is the wave of the future, a wave that is has long been awaited in the medical world. In time, genetic editing will be remembered as the discovery of a millennium.