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Gene Therapy - Types, Risks, and Uses

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

Written by

Hemamalini. R

Medically reviewed by

Dr. Kaushal Bhavsar

Published At February 28, 2023
Reviewed AtMarch 27, 2023


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.

Frequently Asked Questions


Can an Example of Gene Therapy Be Given?

An example of gene therapy is the treatment of severe combined immunodeficiency (SCID), commonly known as "bubble boy" disease. This involves inserting a functional copy of the faulty gene into the patient's cells to restore immune function.


What Advantages Are Associated with Gene Therapy?

Gene therapy holds significant promise in the treatment of various genetic disorders. Some advantages include the potential for long-term treatment effects, as the corrected genes can theoretically provide lasting benefits. It also offers the possibility of treating the root cause of a disease rather than just managing its symptoms.


Provide A List of Five Applications of Gene Therapy.

Gene therapy is applied in treating the following:
- Genetic disorders.
- Cancer.
- Inherited diseases.
- Cardiovascular conditions.
- Neurodegenerative disorders.


Who Is Credited with the Introduction of Gene Therapy?

The concept of gene therapy was introduced by Dr. William French Anderson and his colleagues in 1990 when they successfully used a retroviral vector to deliver a therapeutic gene to a patient with a genetic disorder.


What Are the Fundamental Steps of Gene Therapy?

Gene therapy involves the following steps:
- Selecting the therapeutic gene.
- Delivering it into the target cells
- Ensuring its proper expression.
- Monitoring the patient's response.


What Are the Pros and Cons of Employing Gene Therapy?

Pros include the Potential for long-term treatment, addressing the root cause of genetic disorders, personalized medicine, and a wide scope of treatable diseases, including genetic disorders and some cancers. Cons encompass risks, ethical concerns, and varying success rates.


Elaborate on the Historical Development of Gene Therapy.

Gene therapy evolved from early genetic research in the 20th century, culminating in the first successful clinical trials in the late 1980s and early 1990s. Initial setbacks led to improved safety and efficacy measures over time.


How Did the Term "Gene Therapy" Originate?

The term "gene therapy" originated in the 1960s, coining the idea of treating genetic disorders by introducing genes into cells.  Initially, scientists used the term "gene surgery" to describe the process, but it later evolved into "gene therapy" to reflect the idea of using genetic material as a therapeutic intervention for various diseases.


In Which Fields or Contexts Is Gene Therapy Utilized?

Gene therapy is utilized in medicine to treat genetic and acquired disorders, in biotechnology for genetic engineering, and in research to advance our understanding of genetics and cellular processes.


What Is Another Term for Gene Therapy?

Another term for gene therapy is "genetic intervention." This term also encompasses the idea of using genetic material to intervene and treat various diseases or disorders. While "gene therapy" is the commonly used term, "genetic intervention" can be used to describe the broader scope of genetic treatments and modifications.


What Is the Typical Success Rate of Gene Therapy?

Success rates vary depending on factors such as the disease, delivery method, and patient response. Advances in viral vectors and genome editing technologies are enhancing overall success rates.


How Do Viruses Play a Role in Gene Therapy?

Viruses play a crucial role in gene therapy as they can be used as vectors to deliver therapeutic genes into target cells. Specifically, modified viruses, such as retroviruses, adenoviruses, or adeno-associated viruses, are employed to transport genetic material into the cells of the patient.


What Are the Key Takeaways from Gene Therapy?

Some key takeaways from gene therapy include its potential for long-term treatment effects, the ability to address the root cause of genetic disorders, and the prospects of personalized medicine. However, it is essential to consider the risks associated with immune responses, potential off-target effects, high treatment costs, challenges in gene delivery, and the ethical implications of human gene modification.


Which Illnesses Can Potentially Be Treated Through Gene Therapy?

Gene therapy holds promise for treating a range of illnesses, including inherited genetic disorders like cystic fibrosis, hemophilia, muscular dystrophy, and sickle cell anemia. Additionally, it shows potential in addressing various types of cancer by targeting specific genes involved in tumor growth.


Does Gene Therapy Offer a Permanent Solution?

Gene therapy has the potential to offer long-lasting or even permanent solutions for certain genetic disorders. Introducing functional genes into the patient's cells can provide a lasting therapeutic effect, potentially addressing the root cause of the illness. However, the permanence of the treatment can depend on various factors, including the type of disorder being treated, the specific genetic mechanism involved, and the effectiveness of the gene delivery system.


Why Is the Future Significance of Gene Therapy Emphasized?

The future significance of gene therapy is emphasized due to its potential to revolutionize the treatment of numerous genetic and acquired diseases. It holds promise for providing long-term and possibly permanent solutions, addressing the root causes of various illnesses.
Dr. Kaushal Bhavsar
Dr. Kaushal Bhavsar

Pulmonology (Asthma Doctors)


gene therapy
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