What Is Gene Therapy?
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Gene Therapy - Types, Risks, and Uses

Published on Feb 28, 2023 and last reviewed on Mar 27, 2023   -  4 min read


Gene therapy is a medical technique used to prevent or treat disease. To learn more about gene therapy, read the full article below.


Gene therapy is a medical technique that prevents or treats disease by correcting the underlying genetic defect. Instead of drugs or surgery, gene therapy techniques allow doctors to treat a condition by altering a person's genetic composition. When a gene mutation causes a protein to be missing or defective, gene therapy may be able to restore that protein's normal function. There are various approaches to gene therapy:

  • Introducing a new or modified gene copy to aid in treating a disease.

  • Turning genes on or off to prevent disease.

  • Replacing a healthy copy of a gene for the disease-causing sequence.

What Are the Types of Gene Therapy?

Based on the types of cells treated, there are two types of gene therapy including:

Somatic Gene Therapy - This type is considered the best and safest gene therapy and is most commonly found in human somatic cells. This gene therapy transfers therapeutic genes into the human body's somatic cells or stem cells.

Germline Gene Therapy - It occurs in human germline cells. This method is usually used to treat genetic, disease-causing gene variants passed down from parents to their offspring. The procedure involves inserting healthy DNA into the cells that produce reproductive cells like eggs or sperm. However, many countries prohibit this gene therapy since the risks exceed the benefits.

How Does Gene Therapy Work?

Gene therapy works by inactivating or replacing disease-causing genes. In certain instances, it involves adding new genes to the body to treat a particular disease. With this therapy, medical professionals provide a healthy copy of a gene to cells within the body. This healthy gene can either inactivate a mutated gene, replace a mutant (damaged) gene, or introduce an entirely new gene.

Vectors, which are carriers, deliver these healthy genes into cells. A vector is similar to a package used to send a specific message. Certain viruses are used as vectors since they can transfer the material to the cell by infecting it. The vectors are usually modified viruses that do not cause disease. Vectors could also be bacteria or circular DNA molecules (plasmid DNA). The use of nanoparticles, the encapsulation of lipid molecules, and the use of electric currents are other methods to package and deliver genetic material that are now being intensively researched.

There are two methods for delivering the vector:

  • Ex-vivo: This treatment involves taking out the patient's cells and transferring their genetic material to these cells outside of the body. The modified cells are then delivered.

  • In-vivo: This treatment means that the genetic material is administered directly to the person through an injection.

What Are the Possible Risks Associated With Gene Therapy?

There are some known possible risks associated with gene therapy. Lack of effectiveness has been the main concern with gene therapy. However, there may be some adverse effects.

The following risks are associated with this therapy:

  • Unwanted Immune System Reaction: Immune system involvement in gene therapy has the potential to react with healthy cells that resemble disease cells, thereby damaging healthy cells.

  • Target the Wrong Cells: Gene therapy may cause an immune response that affects the wrong cell type instead of the intended target cells. If this occurs, healthy cells may be damaged, resulting in illnesses or diseases like cancer.

  • Possible Tumor: If the new genes are in the wrong place in your DNA, they may cause tumor growth.

  • Infection Caused by Viral Vector: When a viral vector is used, there is a possibility that the virus will infect the person. Depending on the primary disease being treated, a patient undergoing gene therapy may have a weakened immune system and have trouble fighting the viruses.

What Should We Expect From Gene Therapy?

While considering gene therapy, it is essential to go through the procedures of diagnosis, treatment, and medical surveillance to determine the effects.

How Can Gene Therapy Be Used to Diagnose Various Diseases?

This diagnostic step will identify whether the medical problem can be treated with gene therapy. It indicates that a blood sample would be sent to a laboratory to find any therapeutic gene alterations related to the medical condition.

Gene therapy may be used to treat a variety of conditions, including:

Sickle Cell Disease: It is an inherited disorder that causes abnormal hemoglobin production (the protein that transports oxygen in red blood cells).

Cystic Fibrosis: A hereditary condition in which thick mucus obstructs the airways and prevents digestive enzymes from secreting.

Inherited or Acquired Retinal Disease: It is a condition that damages the retina, which may cause blindness or vision loss.

Leber’s Hereditary Optic Neuropathy (LHON): An inherited condition that damages central vision by causing the loss of optic nerve cells.

Autosomal Recessive Spinocerebellar Ataxia 12 (SCAR12): An inherited condition that causes infantile seizures, delays in development, and a lack of motor coordination.

WW domain-Containing Oxidoreductase Epileptic Encephalopathy Syndrome: An genetic condition that causes epilepsy, developmental delays, and early death.

Cancer - It includes many types of cancer that are treated by gene therapy.

How Does Gene Therapy Help in Treatment?

A viral vector or liposome may be used to transfer the genes into your cells as part of the treatment. After the treatment, the modified cells will be restored to the body.

The effectiveness of the treatment will be evaluated, and the patient will be monitored for adverse events (side effects). If this happens, they may need to be treated again.

What Is Clinical Trial In Gene Therapy?

Currently, taking part in a clinical trial is the only way to receive gene therapy. There are three stages to the clinical trial process. Phase I studies examine the adverse effects of treatment and determine whether it is safe for humans. Phase II trials examine whether the treatment is effective or whether it works. Phase III trials compare the novel or new treatment with the currently accessible treatments. It assists doctors in determining whether a gene therapy approach is safe for people.


Gene therapy is a relatively new treatment that aims to treat disease by regulating the production of proteins by faulty genes. If the person has a hereditary condition with a known and identified gene mutation, they must participate in a gene therapy clinical trial. Please consult your doctor about gene therapy to know whether it is safe and effective.

Last reviewed at:
27 Mar 2023  -  4 min read




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