The Food and Drug Administration on Thursday approved a new gene therapy for Sanfilippo syndrome type A, an ultra-rare disease sometimes known as childhood Alzheimer’s.

The therapy, called Fayuvi, was developed by Ultragenyx. It is the first drug specifically approved to treat Sanfilippo. Ultragenyx did not immediately release a price.

“It’s hard to overstate what this approval would mean for everybody who is living with this really horrific disease and watching their children suffer and pass away early, and all the rest that it brings,” Cara O’Neill, chief science officer of the Cure Sanfilippo Foundation, said in an interview earlier this week. “This, gosh, would just finally mean when patients and families receive this shocking diagnosis, they wouldn’t be told to … take their kids home and love them. They would be given hope and an action plan for treatment.”