Frequently Asked Questions

The idea of gene therapy holds the promise of providing a cure for many diseases. Even though gene therapies have demonstrated a long-term therapeutic benefit, they are still relatively new, and the promise of cure has not yet been realized.

Gene therapy is a relatively new type of treatment. While clinical trials often last years and may demonstrate that a therapy is effective during that time, it is difficult to know exactly how long gene therapy will last for each and every person. 

All clinical studies, including those being conducted in gene therapy, are monitored for the safety and effectiveness of a treatment. All treatments have the potential to cause side effects. Discuss these with your health care professional if you are considering any kind of gene therapy.

Gene replacement (a type of gene therapy) is a way to treat genetic diseases. Gene replacement replaces the function of a malfunctioning gene with a new, working copy of the gene.

Gene replacement aims to give the body a new, working copy of a malfunctioning gene. The new gene sits inside the nucleus, or control center, of cells and allows the cells to produce the missing protein critical for the body to function. 

Viruses are used in gene replacement because of their natural ability to enter into the cells of the body. In gene replacement, scientists alter or reengineer a virus so it can be used as a vector, or delivery vehicle, without causing disease in humans. The vector acts like an envelope in that it holds the new, working copy of the gene and delivers it to where it needs to go in the body. 

A monogenic disease can be caused by a mutation on one gene. Because gene replacement delivers a new, working gene to the body, it has the potential to help people with monogenic diseases.

While certain viruses are used as vectors, the vehicles used to carry the new working genes into the nucleus of the cell, scientists have removed the disease-causing parts of the virus and changed them in ways that stop them from making you sick. 

Some of the risks of gene replacement have to do with the viral vectors used to deliver the new gene into the cell. Risks vary depending on the specific gene therapy, the viral vector used, and the disease being treated. An example of a risk is: Unwanted immune system reaction. Your body's immune system may see the newly introduced vector or working gene as an intruder and attack it. This may cause the new, working gene to never make it to the target cells or be lost once in the cells. 

If you are considering gene therapy, it is important to discuss the potential risks and benefits with your healthcare provider first.

There are several different types of gene therapies. Gene replacement replaces the function of a malfunctioning gene with a new, working copy of the gene. Other types of gene therapies may insert, remove, or change specific pieces of a person’s existing DNA or change how certain cells act.

Gene addition delivers a new gene into the body to target a specific aspect of what causes disease and can supplement another medication that targets that same aspect to help it work better at treating that disease.

What may be confusing about gene replacement and gene addition (because they sound similar) is that in gene replacement a gene that is normally found in the body is added, and with gene addition a gene that is novel to the body is added.

Gene inhibition involves deactivating or “silencing” the expression of a mutated gene that codes for a toxic protein or too much protein. 

This technique aims to repair the altered gene by inserting, removing, or changing specific pieces of a person’s existing DNA. 

Gene editing enables scientists to insert, remove, or change part of person’s DNA at a specific spot along their DNA.

Gene replacement replaces the function of a malfunctioning gene with a new, working copy of the gene.