How does gene therapy fix diseases at the DNA level?

The answer

Gene therapy treats diseases by introducing, altering, or replacing genetic material within a patient's cells. Viral vectors (modified viruses stripped of harmful genes) are commonly used to deliver therapeutic DNA into cells. In 2017, the FDA approved Luxturna, which restores vision in patients with a rare inherited retinal dystrophy by delivering a functional copy of the RPE65 gene directly into the eye. More recently, CRISPR-based therapies have enabled precise editing of specific DNA sequences, with the first CRISPR therapy (Casgevy for sickle cell disease) approved in 2023.