The world won't know until later this year whether a novel treatment for blindness has restored patients' vision, but for now, "to even have the possibility—it's a gift," one participant tells NPR. Michael Kalberer is 43 and legally blind, and he agreed to let scientists at Editas Medicine of Cambridge, Mass., use the gene-editing technique known as CRISPR on one of his eyes. While CRISPR has been employed previously against other diseases, that has always involved removing genes from a person's body, "editing" them in a lab, and then replacing them in the body, writes Rob Stein. However, that process won't work for the eyes because cells of the retina are too delicate. This study, then, marks the first time scientists are trying to edit and thus repair genes inside patients' bodies.
"It sounds a bit like science fiction to be injecting billions of tiny little virus particles under the retina so that they can go make spelling corrections of the gene inside a patient's own retinal cells," says Dr. Eric Pierce of Mass Eye and Ear. "But it's really happening." All four patients treated so far suffer from a rare genetic disorder known as Leber congenital amaurosis, and researchers hope to have data to report later in 2021. Assuming all goes well, six more adults and eight children will undergo the procedure next. Success could open the door for treatment of other disorders in which genes can't be removed from the body, including Huntington's and muscular dystrophy. In the Conversation, ophthalmology researcher Hemant Khanna, who isn't involved in the study, details the process and writes that it "holds immense promise." (Read more CRISPR stories.)