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Gene therapy is the correction of defective genes in order to treat diseases.

What does gene replacement therapy do?
Graphical image of a broken double helix

What can cause a genetic disease?

Genes are made up of deoxyribonucleic acid (DNA) and come in pairs, one from each parent. Genes store the code—the information and instructions—the body needs to make proteins. Nearly every function of the body is made possible by proteins. When a piece of DNA is missing or changed, it can alter protein production, the protein may no longer be able to carry out its normal function. So even if a single protein is missing, in short supply, or made wrong, the effect on the body can be harmful. Some genetic diseases are caused by a malfunctioning or missing gene or genes.

A genetic disease can be passed down from one or both parents or can be a result of random errors in the body’s genes.


What is the science behind gene replacement therapy?
A double helix coming out of a hand

How can gene therapy help?

Gene therapy is a key treatment strategy for disorders caused by a missing or faulty gene and may involve addition, inhibition, editing, or functional replacement of a gene. 

Gene therapies are designed to be one-time treatments that target the genetic root cause of diseases.


What are the key components of gene replacement therapy?
A double helix inside a barcoded test tube

Gene Replacement

When a gene is altered or missing, the supply of an important protein can be reduced, causing disease.

Gene replacement uses a new, working gene to replace the function of a nonworking or missing gene. This gene then provides the instructions for your body to make the missing or insufficient protein.

Learn more about gene replacement


Are there different types of gene-based therapies?
A double helix inside a transparent pill

Gene Addition

Gene addition involves the introduction of a new gene into the body to target a specific aspect of what causes the disease.

Learn more about gene addition

Are gene-based therapies new?
Graphical image of a double helix with a glowing center

Gene Inhibition

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

Learn more about gene inhibition

Insertion of missing part of helix

Gene Editing

The mutant gene that is causing disease is edited in order to correct the mutation.

Learn more about gene editing

Family sharing a cup of coffee

Are gene therapies new?

Scientists have been investigating for decades how gene therapies can be used to treat genetic diseases.

Discover the history of gene therapies