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What is a genetic disease?

Some genetic diseases are caused by a malfunctioning or missing gene or genes. Genetic diseases can be passed down from one or both parents, or can be a result of random errors in the body’s genes. 

What is a monogenic disease?

A monogenic disease is a disease caused by a mutation in a single gene or gene pair. Gene replacement is commonly used for monogenic diseases, as only one malfunctioning gene needs to be treated.

Learn more about types of monogenic diseases

Overhead shot of adult and child hands touching young tree bud in soil

What is the goal of gene replacement?

When our own genes do their jobs, they encode for the production of necessary proteins.

In a person with a monogenic disease, there is one gene or gene pair that is missing or does not work right. This can result in the protein being made incorrectly, made in short supply, or not made at all.

The goal of gene replacement, a type of gene therapy, is to give cells a new, working copy of the missing or nonworking gene. This new gene is able to give the body instructions for making a particular protein the body needs.


A diagram of the genes of a person without a monogenic disease
A diagram of the genes of a person with a monogenic disease
A diagram of a monogenic disease with gene replacement

Check your understanding of gene replacement

How does gene replacement aim to treat genetic diseases?

Gene replacement uses a new, working gene to treat genetic diseases. This new gene provides the body with instructions for making the particular protein that was missing or in short supply.

Learn how gene replacement works