LONDON — A baby girl born with profound genetic deafness can now hear unaided after receiving a “groundbreaking” gene therapy trial, Britain’s National Health Service said Thursday.

Opal Sandy, an 18-month-old from Oxfordshire, England, is the first patient treated in a global gene therapy trial that is showing “mind-blowing” results, Addenbrooke’s Hospital in Cambridge said in a statement. Sandy is “the first British patient in the world and the youngest child to receive this type of treatment,” the hospital said.