Genes contain DNA

Genes contain DNA — the code that controls much of the body's form and function. DNA controls everything from hair color and height to breathing, walking and digesting food. Genes that don't work properly can cause disease. Sometimes these genes are called mutations.

Gene therapy aims to fix a faulty gene or replace it with a healthy gene to try to cure disease or make the body better able to fight disease. It holds promise as a treatment for a wide range of diseases, such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS.

Why it's done

Gene therapy is done to:

Fix genes that don't work properly. Faulty genes that cause disease could be turned off so that they no longer promote disease. Or healthy genes that help prevent disease could be turned on so that they could stop the disease. Replace genes that don't work properly. Some cells become diseased because certain genes don't work properly or no longer work at all. Replacing these genes with healthy genes may help treat certain diseases. For example, a gene called p53 usually prevents tumor growth. Several types of cancer have been linked to problems with the p53 gene. If healthcare professionals could replace the faulty p53 gene, the healthy gene might cause the cancer cells to die. Make the immune system aware of diseased cells. In some cases, your immune system doesn't attack diseased cells because it doesn't see them as intruders. Healthcare professionals could use gene therapy to train your immune system to see these cells as a threat.