Gene-therapy approaches

What is gene addition?

Gene addition is a type of gene therapy that targets a specific gene in the body’s cells. This approach adds a working copy of a gene into the cell or adds another gene to bypass the problem. The added gene allows the body to make proteins to potentially manage or treat a genetic disease.

Delivering the gene

Delivering the gene

To introduce a new gene through gene addition, a vehicle is needed to deliver the material to the intended target.

You can think of this vehicle as an envelope carrying the new gene to its destination. The vehicle is called a vector.

A viral vector is 1 type of vector. It is commonly used because viruses are naturally very good at entering cells.

To create a vector, scientists take a virus cell and inactivate it by only using parts of the virus. What remains is similar to an outline of the virus—it’s like an empty envelope that scientists reuse to package the working gene.

Illustration showing a new gene being  packaged inside of a vector
Illustration showing a new gene being  packaged inside of a vector

How gene addition works


Scientists create a working copy of the gene in a lab and place it inside the vector.


The vector carries the new gene to the targeted location inside the cells.


The vector unpacks the new gene, like taking a letter out of an envelope.


The new gene tells the body how to build proteins to potentially change the way the body functions.

Vector quick facts

  • Modified viral vectors do not contain disease-causing genes.
  • The target cell breaks down the vector after it has delivered the gene.
  • Research is advancing for viral vectors and how they can be used to help treat genetic diseases.

Now that you have had a glimpse of gene addition, 1 type of gene therapy, let’s move on to another type known as gene editing.

Learn about gene editing

Learn more

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