Spark Therapeutics’ Luxturna has become the first gene therapy ever to be approved by the US Food and Drug Administration for an inherited condition.

The regulator has cleared the one-time treatment for use in patients with confirmed biallelic RPE65 mutation-associated retinal dystrophy.

Inherited retinal diseases (also known as inherited retinal dystrophies) are a group of rare blinding conditions caused by one of more than 220 different genes.

Between 1,000-2,000 people in the US are estimated to have vision loss due to biallelic RPE65 mutations, while an expected 10-20 new patients a year are born these genetic abnormalities in the country every year.

Luxturna works by delivering a normal copy of the RPE65 gene directly to retinal cells, which then produce the normal protein that converts light to an electrical signal in the retina to restore patient’s vision loss.

The therapy uses a naturally occurring adeno-associated virus, which has been modified using recombinant DNA techniques, as a vehicle to deliver the normal human RPE65 gene to the retinal cells to restore vision.

Luxturna was approved by FDA under priority review, after data from clinical trials showed that patients who received the therapy demonstrated significant improvements in their ability to complete the obstacle course at low light levels as compared to the control group.