Gene therapy: fixing a faulty gene

0:00Some diseases are caused by one faulty gene. Can we treat them by fixing it?

0:06Inside the nucleus is DNA. A gene is a section of DNA with the instructions for making a protein.

0:15A change in a gene is a mutation. A faulty gene can stop the cell making a working protein, causing disease.

0:23Gene therapy changes genes in some of the patient's cells, in two main ways.

0:29One way adds a working copy of the gene, often carried by a harmless virus called a vector.

0:36The virus delivers the working copy to the nucleus, so now the cell can make the working protein.

0:44The other way is gene editing: a tool cuts the DNA at the faulty gene and changes it.

0:52In 2017, a gene therapy using a virus was approved for one form of inherited blindness.

0:59In 2023, gene editing was approved for sickle cell disease, an inherited blood disorder.

1:06The patient's own blood stem cells, which make new blood cells, are taken out, edited in a lab and put back.

1:15Gene therapy does not change every cell in the body, only the treated cells and the new cells they make.

1:22These are body cells, not egg or sperm cells, so the change is not passed on to children.

1:29A treatment can cost over a million dollars, and there are risks, such as an immune reaction or an edit in the wrong place.

1:38This raises ethical questions: who should get these treatments, and who should pay?

1:45Gene therapy treats disease by adding or editing a gene in some body cells.