How Can Gene Therapy Cure or Treat Diseases?
Gene therapy is an experimental method of treating certain diseases without resorting to surgery or traditional medication. The idea is straightforward at first glance. In this process, a nonfunctional gene is swapped out with a functional one to deal with a particular disease.
Inherited genes that prevent the production of essential proteins can leave certain people vulnerable to illness. Through gene therapy, doctors can insert a healthy copy of a gene into a patient’s DNA. Theoretically, the condition can be cured by providing the body with the necessary protein. Mutations in DNA can alter how your body functions, but gene therapy can correct or replace these changes.
Gene therapy, often known as “gene editing,” allows doctors to change a patient’s genetic code permanently. Diseases like beta-thalassemia and spinal muscular atrophy (SMA) are thought to benefit from this strategy because they result from a single mutation. Some tumors may be treatable using gene editing.
In this article, we will discuss more about gene therapy and how it can help with dealing with various diseases and issues, along with its benefits and drawbacks.
The Procedure of Gene Therapy
Genes are pieces of DNA that, under certain circumstances, direct your cells to produce a desired protein.
However, if your DNA is mutated, your cells may produce either too much or too little of the protein you need. The body is like a computer program in that even a single line of code can have far-reaching consequences.
This problem can be solved via gene therapy through-
- Switching off malfunctioning and defective genes
- Introducing new genes improves immune cells’ ability to identify and destroy infected cells.
- Some disorders may be treated by inserting a healthy gene copy instead of the mutant or defective one.
- Correction of dysfunctional genes caused by mutations. It is possible to accomplish this by introducing or activating healthy genes that aid in disease prevention or by silencing the mutant genes responsible for disease promotion.
- Raising the immune system’s awareness of diseased cells. Diseased cells may go unchecked when the immune system fails to identify them as foreign invaders. Gene therapy may help doctors teach the body to identify better and destroy dangerous cells.
There are no tweezers small enough for scientists to change your DNA manually. Instead, they enlist the help of an unlikely ally; viruses.
Typically, a virus would invade your cells, tamper with your DNA, and then replicate inside your cells. However, researchers can replace the virus’s harmful code with their beneficial version. These vectors can’t make you sick like a conventional virus since they lack the necessary components.
Nonviral vectors also exist, as gene therapies that employ nonviral vectors, including lipid molecules or magnetic nanoparticles, are still the subject of intensive research. But so far, none of them have been green-lit.
Types of Gene Therapy
Gene therapy can be split into two categories:
In vivo (within your body)
The new genes are delivered to your body via injection or intravenous (IV) infusion of the vector created by the scientists.
Ex vivo (outside your body)
Scientists take cells from your body and put them in a petri dish with the vector. After being modified, your cells are put back into your body, where they can hopefully multiply.
There are certain advantages to each type:
Benefits of In Vivo Therapy
- Can transport vectors systemically, which helps with disorders of the bone and blood.
- Easier and less time-consuming
Benefits of Ex Vivo Therapy
- Ability to focus on particular tissues or organs.
- Reduce potential dangers to a minimum
In contrast to genetic engineering, which modifies DNA in healthy organisms to benefit specific qualities, gene therapy does not include altering the genome. Potentially, genetic engineering could alter an infant’s eye color or lessen their vulnerability to certain diseases. However, there is still a lot of backlash against it because of how near it is to eugenics.
Diseases and Issues Gene Therapy Can Help With
Several genetic disorders are amenable to treatment with gene therapy:
Hereditary Vision Loss
The inability of the eyes to convert light into electrical signals results from a malfunction of the RPE65 gene in the retinas. Your retinal cells can receive a functional copy of a new RPE64 gene thanks to Luxturna, a gene therapy that the FDA approved in 2017.
Hemophilia B can be treated with Hemgenix, which the FDA has approved. The viral vector stimulates the blood-clotting factor IX protein production in the liver.
By giving your bone marrow stem cells the necessary instructions so they can produce hemoglobin, the FDA-approved gene therapy Zynteglo to treat beta-thalassemia in 2022. Because of its effect on hemoglobin formation, this blood condition can reduce the amount of oxygen reaching the body’s tissues.
Spinal Muscular Atrophy (SMA)
A lack of “survival of motor neuron” (SMN) proteins, which are required for developing and maintaining motor neurons, causes infantile-onset SMA. Babies slowly lose the ability to move and breathe without these neurons. The FDA approved gene therapy Zolgensma in 2019 to replace defective SMN1 genes in developing motor neurons with genes that can produce adequate SMN proteins.
Cerebral Adrenoleukodystrophy (CALD)
Your ABCD1 gene encodes the enzyme responsible for metabolizing fatty acids in your brain. A dysfunctional or absent copy of this gene causes cerebral adrenoleukodystrophy. In order to prevent the accumulation of fatty acids and subsequent brain damage, the FDA has approved Skysona for use in 2022.
Non-Hodgkin’s lymphoma and multiple myeloma are only two of the many cancers for which the Food and Drug Administration has given gene treatments the green light.
Most cancer gene therapies put new genes into a very effective antibody type called a T cell, which attacks the disease indirectly.
After being modified, your T cells can recognize and eradicate cancer cells like they remove viruses. Adstiladrin, a therapy authorized by the FDA in 2022, can alter the DNA of your bladder cells to treat nonmuscle-invasive bladder cancer.
Is Gene Therapy Safe?
Some potential gene therapy patients may be wary of injecting viruses into their bodies. So, it is essential to remember that considerable testing is done on gene therapies before they are approved. In the same way, many vaccines prevent viruses from replicating; gene treatments repair the viruses so they can’t spread. However, gene therapies may carry additional dangers:
Viruses can masquerade as other threats, leading your immune system to overreact. Side effects include fever, irritation, and exhaustion from the influx of white blood cells.
The viral vector runs the danger of accidentally inserting its genetic cargo into a new mutation in the wrong region of DNA. Such mutations caused cancer in one person in 2002. However, “smarter” vectors with improved accuracy have been constructed recently.
Unknown Long-Term Effects
The long-term effects of gene treatments remain unknown because the field is still in its infancy. Inadvertent editing of egg or sperm cells by viral vectors has raised concerns that mutations could be passed on to future generations.
Regardless of these concerns, most scientists agree that the benefits of gene therapy outweigh the risks. The majority of gene therapy cases involve potentially fatal diseases. In many cases, the benefits of treatment outweigh the possibility of unwanted effects.
Drawbacks of Gene Therapy
The limitations of gene therapy prevent it from replacing conventional medical care on a larger scale, like-
Specific mutations are off-limits to gene therapy. This suggests that it may not be effective for everyone with that problem. Two people, for instance, may have a genetic predisposition for blindness. Only the RPE64 mutation is amenable to gene therapy for treating vision loss.
Due to the novelty of gene therapy research, professionals ensure the treatment’s safety through rigorous testing before releasing it to the general public. The FDA may take years to approve each novel treatment.
As you might expect, gene therapies come with a hefty price tag. This has implications for both the cost of the treatment and the ability to conduct clinical studies. At $2.1 million per dose, Zolgensma, a gene therapy, is the most costly medicine in the United States. That cost is still prohibitive, even with insurance, for the typical American.
So that more people might benefit from gene therapy, researchers are exploring ways to make its development safer, cheaper, and more efficient.
Gene therapy has successfully treated a wide range of genetic disorders by correcting the underlying mutations. More conditions may be amenable to this technology’s treatment as it is developed and perfected. To ensure that those needing gene therapy have easier access to it, researchers are also looking into ways to lower the cost of the treatment. Although the researchers are optimistic, they are also cautious due to the field’s turbulent history. Hopefully, this therapy will get more and more developed with time and will be able to help with a lot of physical issues that modern medicine fails to help with and also come within reach of ordinary people.