In the largest and longest trial of its kind, a gene therapy for congenital deafness, 90% of patients with inherited deafness showed significant improvements in their hearing over the next several years. The trial, which involved 42 people, was conducted across eight sites in China and mostly involved children, but also included three adults, two of whom responded well to the therapy. The results suggest that adults could benefit from the treatment. The study's co-author, Dr. Chen, predicts that in the coming years, many trials will be conducted for different types of genetic hearing loss. The therapy distributes working copies of the defective OTOF gene into the inner ear, restoring its function.