Genes are sections of DNA in your cells, inherited from your parents — one copy of each gene from each parent. They carry the information that shapes what you look like and how your body works.
What genes do
About 20,000 genes carry instructions for making proteins, which your body needs to function. Other genes don’t make proteins themselves but act like switches, turning other genes on or off — helping decide when, where and how much of a protein is made.
When genes change
Changes in genes are called variants or mutations. They can be inherited, happen as you age, or come from environmental causes such as chemicals or radiation. Often they have no effect, but even a small change can alter a protein’s instructions — and if genes don’t make the right proteins, or make them wrongly, the result can be a genetic disorder.
What gene therapy is
Gene therapy treats or prevents disease by changing genetic material rather than using traditional medicines or surgery. New genetic material can be delivered two ways:
| Method | How it works |
|---|---|
| Ex vivo | cells are removed from your body, modified, then put back |
| In vivo | genetic material is delivered directly into your body, often by injection |
Approaches include:
- inserting a normal gene to replace an abnormal one — a common form
- repairing an abnormal gene
- changing how much a gene is turned on or off
- genome (gene) editing, which changes the DNA already in your cells rather than adding new material — CRISPR-Cas9 is a well-known example, still being studied for genetic disorders
- cell-based gene therapy, which combines gene and cell therapy — for example CAR T cell therapy, in which cells, often immune cells, are genetically altered to treat a disease and then returned to the body
So far, gene therapies are approved for only a small number of diseases, such as Leber congenital amaurosis, an inherited eye disorder, and spinal muscular atrophy, a genetic muscle disorder.
Risks and challenges
Research continues to make sure these treatments are safe and effective. Challenges include:
- immune reactions — the body may treat the new material as a threat
- unintended effects — DNA changes could harm other genes
- high cost — gene therapies are often expensive and not widely available
Sources
Based on "Genes and Gene Therapy," MedlinePlus, U.S. National Library of Medicine; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from medlineplus.gov
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