How Does Gene Therapy Work?

Gene therapy aims to correct diseases at their genetic root. In gene addition, a working copy of a defective gene is inserted into the patient's cells, usually using a modified virus (adeno-associated virus or lentivirus) as a delivery vehicle (vector). The virus enters cells and deposits its therapeutic DNA payload without causing disease. In gene editing approaches (like CRISPR-Cas9), molecular scissors cut the DNA at a precise location to disable a harmful gene or correct a mutation in place. Luxturna, approved in 2017, treats inherited retinal blindness by delivering a functional RPE65 gene directly into the eye. As of 2024, over 20 gene therapies have received regulatory approval worldwide, treating conditions from spinal muscular atrophy to sickle cell disease.