Gene Therapy Basics

Getting to the Root Cause of Cardiomyopathy

Gene therapy holds the potential to treat the root cause of cardiomyopathy by targeting the genes that can lead to the condition. The future of gene therapy offers hope for those affected by cardiomyopathy, beyond just symptom management.

What is Gene Therapy?

Gene therapy is a way of treating or preventing conditions caused by genetic mutations.

Think of genes as the blueprints for your body. When some parts are missing or there are mistakes in these blueprints, gene therapy may be used to correct those mistakes. Gene therapy is a process that involves bringing a working gene into the body to fix the mistakes in the blueprints and instruct the cells how to work properly.

How Does Gene Therapy Work?

Click HERE to view an infographic about how Gene Therapy works or watch the video below.

Infographic and video provided by ASGCT

Vectors – Special Delivery Vehicles:

To bring a working gene into the body and send it where it needs to go, the gene needs a specialized delivery vehicle. These delivery vehicles are called “vectors” and they help the working gene travel to specific cells in the body. It’s like delivering a package with the instructions (or “blueprints”) for a cell inside it. The job of a vector is to insert a new working gene into the cell, sort of like updating the instructions for the cell’s work.

The Role of Modified Viruses as Vectors (vehicles):

Modified viruses are often used as “vectors” because they’re good at entering cells to deliver a working gene. It is important to note that before using a virus in this way, scientists remove any part of the virus that can cause illness.

Adeno-associated viruses (AAV)

AAV are often used as vectors in gene therapy because they are naturally occurring viruses and are not known to cause symptoms or diseases in people. In AAV gene therapy, a modified adeno-associated virus is used to deliver the working gene into the cells that need it. The working gene then updates the cell’s instructions to work properly. When AAV is used as a viral vector (or viral carrier) in gene therapy, usually only one dose is required to get to the root of the disease to fix the problem inside your cells.

Types of Gene Therapy

There are several types of gene therapy. When learning about gene therapy, you may see terms such as gene addition (which includes AAV), gene silencing, and gene editing, often referred to as “CRISPR.”

While there are several types of gene therapy, only AAV (adeno-associated virus) gene therapy is currently being investigated to treat cardiomyopathy and for that reason, this content will focus on AAV gene therapy.

Antibody Testing and Why It’s Important in Gene Therapy

What is an Antibody? 

An antibody is a protein made by the immune system, which helps the body fight off infection by identifying and destroying harmful bacteria and viruses.

How does a person make antibodies to a virus? 

When the immune system finds a new virus in the body, it makes antibodies to attack and destroy it.  The immune system also remembers the virus.  If the same virus invades the body again, the immune system makes the same antibodies, called pre-existing antibodies, to help prevent another infection. 

What is Antibody Testing and why is it important in gene therapy?

Because AAV gene therapy uses viruses to deliver the working gene into the body, it is important to test the person’s immune system to see if they have pre-existing antibodies to these viruses. An antibody test can tell if a person has been exposed to the virus in the past by looking for antibodies in the bloodstream.

Below are additional reasons antibody testing is important in AAV gene therapy:

  • Safety Evaluation: Identifying antibodies is vital to assess the safety of gene therapy. Antibody testing helps you and your doctors make treatment decisions that are right for you. Individuals with strong immune responses to specific vectors may need different therapies or adjusted treatment plans.
  • Treatment Effectiveness: After gene therapy, antibody testing can help monitor a person’s immune response over time. Existing antibodies from prior exposure to a virus can make gene therapy less effective. Antibody testing is essential to ensure that the therapy continues to work effectively and safely.
  • Research and Development: Antibody test results help advance gene therapy research. This information helps scientists understand immune reactions better, refine vectors, and design more effective treatments.
  • Future Gene Therapy Advancements: As gene therapy progresses, using antibody testing will be crucial for informed treatment decisions and handling possible immune reactions. It’s a key tool for the future of gene therapy.

In summary, antibody testing is a critical part of the gene therapy process. Antibody testing helps to make sure people are safe, keeps an eye on how well the gene therapy treatment is working and helps push gene therapy forward as a groundbreaking medical approach.

  • Has the potential to treat genetic disorders at their core by fixing or changing faulty genes.
  • If given early in the course of a disease, gene therapy might stop any additional damage before it happens.
  • Gives hope to patients with rare diseases who don’t have many treatment options and encourages more research into these less common conditions, as it may:
    • Stop or reverse genetic condition progression
    • Stop or decrease the need for other medications and devices
    • Increase the quality of life
    • Provide a one-time therapy to treat the root cause of a disease and hold the potential to one day prevent or reverse diseases.

Gene therapy holds significant potential, but it’s an evolving field that requires ongoing research to address safety, ethical, and oversight concerns. Despite obstacles, the potential advantages make gene therapy a groundbreaking area of medical progress.

Potential Risks & Challenges

Gene therapy is a new and exciting way to treat diseases, but it is important to be aware of the potential risks and challenges associated with this therapy.

Potential Risks of Gene Therapy

  • Immune system reaction: Your body’s immune system may attack the new gene or the virus that is used to deliver it.
  • Targeting of the incorrect cell: The gene therapy may be delivered to the incorrect type of cell, which could cause problems.
  • Infection: If a virus is used to deliver the gene therapy, there is a risk of infection.
  • Long-term effects unknown: Gene therapy is a new treatment, so we do not know all of the long-term effects. It is possible that there could be both good and bad long-term effects that we are not aware of yet.
  • No guarantees: Gene therapies are still under development, and there is no guarantee that they will work or that they will be safe. The gene therapy may have unexpected side effects. Not all risks are currently known.

Informed Consent

Before you participate in a clinical trial, it is important to understand the risks and benefits of the treatment being studied. This is called informed consent. During the informed consent process, a member of the research team will explain the trial to you and answer any questions you have. They will also give you a written consent form to read and sign. It is important to read and understand the consent form carefully before you sign it.

Potential Challenges of Gene Therapy

  • Time: It takes a long time, often many years, to test potential treatments in clinical trials and get approval from the FDA. It can also take time to find out what gene mutation is causing a person’s symptoms.
  • Not one-size-fits-all: Every disease resulting from a specific genetic mutation requires a tailored gene therapy approach. Currently, most gene therapies can only treat disorders caused by mutations in a single gene. People can have mutations in several different genes but still have the same disease. In this case, they would likely need different gene therapy approaches for each gene mutation. Scientists are working on ways to speed up the development and delivery of personalized gene therapies.
  • Limitations:
    • In general, gene therapy may be able to one day prevent disease progression but can’t correct any damage that has already occurred. Research is ongoing to determine if damage reversal will be possible in the future.
    • Currently, gene therapy can only be given once.
  • Small number of participants: Gene therapy often targets rare diseases, which means that there are few people with the disease. For this reason, it can often take longer to gather enough research data on potential treatments. It can also make it difficult to find enough people who can participate in a clinical trial. Even though each disease may be rare, all rare diseases combined affect an estimated 400 million people worldwide. There are many hard-working patient advocacy groups and foundations working to fund and move research forward in this area.
  • Funding: It costs a lot of money for companies to get ready for a clinical trial, make a gene therapy, and make sure that it is safe for participants.
  • Accuracy required: Gene and cell therapies need to deliver the gene to the right tissue, at the right level, for the right amount of time. This means that scientists need to do a lot of research to find the best way to deliver the gene to the right tissue, at the right level, for the right amount of time. They also need to consider how the person’s immune system will react to the therapy.

Is Gene Therapy Right for You?

*Talk to your doctor before you decide if gene therapy is right for you.

Gene therapy is a new and complex treatment, and it is important to understand the risks and benefits before making a decision. Your doctor can help you weigh the pros and cons of gene therapy and help you decide if it is the best treatment option for you.

Existing Gene Therapies for Other Diseases

Many different gene therapies are being developed. AAV vectors have been used extensively to treat other disease states.

As of November 2023, five AAV gene therapies have been approved by the FDA1:

  • A treatment approved by the FDA in 2017 and is used to treat an inherited retinal (eye) disease (IRD)  that causes blindness.
  • A treatment for adults with hemophilia B was approved by the FDA in 2022.
  • A treatment for children 4-5 years old with Duchenne Muscular dystrophy (DMD) approved by the FDA in 2023.
  • A treatment for pediatric patients less than 2 years of age with spinal muscular atrophy (SMA) due to the SMN1 gene.
  • A treatment for adults with severe hemophilia A approved by the FDA in 2023.

There are many other AAV gene therapies in clinical trials, and it is likely that more will be approved by the FDA in the coming years.

As of November 2023, the following AAV gene therapies have been conditionally approved by the European Medicines Agency (EMA):

  • A treatment for adults with severe hemophilia A.2
  • A treatment for adults and children aged 18 months and older with severe aromatic L-amino acid decarboxylase (AADC) deficiency with a genetically confirmed diagnosis.3
  • A treatment for spinal muscular atrophy (SMA) in pediatric patients.4
  • A treatment for an inherited retinal (eye) disease (IRD) that causes blindness.5 

It is important to note that “conditional approval” means that the EMA has determined that the benefits of the therapy outweigh its risks, but that further data is needed to confirm the therapy’s long-term safety and efficacy. Gene therapy is a rapidly growing field. Numerous clinical trials are underway, exploring the effectiveness of these therapies to treat various diseases.

Common Misconceptions

Common misconceptions about gene therapy can lead to confusion and misunderstanding. Here is a list of some of these misconceptions:

Misconception: Gene therapy can cure any disease.

Reality: Gene therapy is effective for specific diseases with a genetic basis, but it is not a cure-all for all medical conditions.

Misconception: Gene therapy has no risks or side effects.

Reality: Gene therapy can have risks, including immune responses, unintended genetic changes, and unpredictable long-term effects. Not all of the risks are known at this time.

Misconception: Gene therapy is unregulated and experimental, lacking oversight.

Reality: Gene therapy is subject to strict regulations and oversight to ensure safety and efficacy from the clinician trial stage and even after government approval.

Misconception: Gene therapy always involves editing a person’s DNA.

Reality: Gene therapy is currently only performed in somatic cells (non-reproductive cells) to treat diseases. The working gene can NOT be passed from a parent to a child. Therefore, any patient who receives gene therapy today can still pass the mutated gene on to their children.

Misconception: Gene therapy can have harmful genetic mutations.

Reality: Careful testing and safety measures are in place to minimize the risk of introducing unintended genetic changes.

Misconception: Gene therapy always provides a one-time, permanent cure.

Reality: The effectiveness and duration of gene therapy can vary, and some conditions or therapies may require repeat treatments.

Misconception: Gene therapy is readily available to all patients.

Reality: Gene therapy is still evolving, and access may be limited to specific medical centers.

Misconception: Gene therapy is always successful.

Reality: Gene therapy may have varying levels of success, and not all patients respond equally to treatment.

Common Questions

Is gene therapy right for you?

Only you can decide if gene therapy is right for you or a loved one after talking to your doctor and carefully considering all of the options.

What is the underlying genetic condition?

Gene therapy can only be used to treat diseases that are caused by an identified change in a person’s genes. The mutation that is causing the condition or disease must be the same as the gene therapy that is being used to treat it.

What are the potential benefits of gene therapy for this condition?

Gene therapy has the potential to cure or slow the progression of many genetic diseases, sometimes with a single dose. However, it is important to note that gene therapy is still under development, and there is no guarantee that it will be successful for everyone.

What are the risks and potential side effects?

Gene therapy can cause a variety of side effects, including immune system reactions, targeting of the wrong cell, and infection. It is important to talk to your doctor about the specific risks associated with the gene therapy treatment that you are considering. Also, since gene therapy for the heart is in its early development, not all of the risks are known.

Is the treatment experimental or approved?

Some gene therapy treatments are still in the experimental stage and in clinical trials, while others have been approved by the FDA and can be prescribed by doctors. It is important to talk to your doctor about the status of the gene therapy treatment that you are considering.

Are there alternative treatments?

There may be other treatments available for your genetic condition, such as medications or surgery. It is important to talk to your doctor about all of your treatment options before deciding if gene therapy is right for you.

What is the expected timeline for treatment?

The timeline for gene therapy treatment will vary depending on the specific treatment that you are receiving. While current gene therapy is thought to be a one-time administration, most gene therapies involve many tests after being given and the observation period after receiving it can be many years.

Will health insurance cover the cost?

Whether or not your health insurance will cover the cost of gene therapy will depend on your insurance plan. It is important to check with your insurance company to see if gene therapy is covered. However, your insurance won’t be impacted by a clinical trial you may choose to participate in. In this instance, speak with your clinician about how any costs associated with the clinical trial will be covered.

Are there age or health restrictions?

There may be age or health restrictions on eligibility for gene therapy treatment. It is important to talk to your doctor about your eligibility.

What preparations are required before gene therapy?

The preparations required before gene therapy treatment will vary depending on the specific treatment that you are receiving. However, some common preparations include genetic testing, medical evaluations, and physical exams. In many cases, you will be given immunosuppression medications before a gene therapy is delivered and for an amount of time after dosing.  It is important to talk to your doctor about the preparations needed before gene therapy.

Are there long-term monitoring requirements?

After gene therapy treatment, you will need to be monitored by your doctor for a period of time to ensure the safety of the treatment and if it is working as it is intended, known as efficacy.

What is the expected duration of treatment benefits?

The expected duration of treatment benefits will vary depending on the specific gene therapy treatment that you are receiving. However, some gene therapy treatments have the potential to provide lifelong benefits.

Have other patients had successful outcomes?

Yes, many patients with other genetic diseases have had successful outcomes with gene therapy and there are several that have been approved by the Food and Drug Administration (FDA) and health authorities in other countries.  However, it is important to note that many gene therapies are still under development, and there is no guarantee that they will be successful for everyone.

Can I consult with a genetic counselor or specialists?

Yes, you can consult with a genetic counselor or specialist who can provide you with personalized guidance and information about gene therapy.

Are non-viral vectors being explored for gene therapy?

Yes, non-viral vectors are being explored by researchers to overcome the limitations of viral vectors. These non-viral options are less expensive to make compared to their viral counterparts. They may be able to deliver larger genetic packages and allow for multiple treatments. Additionally, non-viral vectors would likely have a lower risk of causing unwanted immune reactions.

If I have gene therapy, can my children still inherit the mutated gene?

Getting AAV gene therapy will not affect your children’s genes. The treatment only affects the recipient’s body cells, not their reproductive cells. As a result, the new gene cannot be passed on to offspring. Therefore, receiving AAV gene therapy will not impact the risk of passing on a genetic condition to your children.


It is important to stay informed about gene therapy and to talk to your doctor about it. Gene therapy is a new and rapidly developing field, and there are many misconceptions about it. It is important to understand the risks and benefits of gene therapy before making a decision*.

Gene therapy is a promising new treatment for cardiomyopathy. By targeting the genetic factors that cause cardiomyopathy, scientists hope to develop new therapies that can cure or slow the progression of the disease.

  1. Approved cellular and gene therapy products. U.S. Food and Drug Administration (FDA); 2022. Accessed November 7, 2023.
  2. 16. Roctavian. European Medicines Agency; 2023. Accessed November 11, 2023.
  3. Upstaza. European Medicines Agency; 2022. Accessed November 11, 2023. 
  4.  Zolgensma. European Medicines Agency; 2022. Accessed November 11, 2023.
  5. EU/3/15/1518 | European Medicines Agency ( Accessed November 20, 2023. 

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