Understanding Genetic Diseases

Gene-based therapies are scientific techniques that use working genes to treat or prevent diseases. Gene replacement therapy is a type of gene-based therapy that uses a new gene to replace a nonworking or missing gene or genes.

What is 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. So even if a single protein is missing, in short supply, or made wrong, the effect on the body can be harmful.

A genetic disease is caused by a nonworking 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.

A baby crawling in grass protected by a parent's hands

What is a monogenic disease? Why is it a good target for gene replacement therapy?

A monogenic disease is caused by a single, nonworking or missing gene or gene pair, and can cause a problem in the body’s ability to make a needed protein.

Monogenic diseases are thought to be ideal candidates for gene replacement therapy because they are caused by mutations, or errors, in a single gene.

Find out which monogenic diseases could be changed by gene replacement therapy.

Why are central nervous system (CNS) diseases an important area of focus for gene replacement therapy?

Diseases that affect the brain and spinal cord and other structures of the CNS are a very important focus for gene replacement therapy. These conditions can be debilitating and progressive, getting worse over time—sometimes in just a few weeks. At this time, many people with CNS diseases have a poor quality of life, and very few effective treatment options exist. There is a great unmet need for the treatment of CNS diseases, which has led to some scientists investigating gene replacement therapy for CNS diseases.

Why is early treatment important for genetic diseases that affect the CNS?

With diseases that affect the CNS, the earlier treatment can be administered, the better. CNS diseases are often progressive, meaning that damage happens over time. For that reason, early treatment may produce better disease outcomes.