Maintenance of the hearing improvement 12 wk after local gene therapy in Ush1g−/− mice. ABR thresholds in 12-wk-old wild-type mice (not injected, n = 5, black curve), Ush1g+/− mice injected with AAV8-GFP (n = 5, blue curve), and Ush1g−/− mice not injected (n = 5, red curve) or injected (n = 5, green curve) with AAV8-Sans-IRES-GFP on P2.5. ABRs were recorded in response to 5- to 40-kHz tone bursts, and for sound levels between 10 and 110 dB SPL. Despite the elevation of the ABR thresholds in the wild-type and injected Ush1g+/− control mice at this age (owing to the C57BL/6 genetic background of the mice) (34), a partial hearing improvement persists in injected Ush1g−/− mice compared with uninjected Ush1g−/− mice (Mann–Whitney test, P < 0.01 for 10 kHz and 15 kHz, P < 0.1 for 5 kHz and 20 kHz, and P > 0.1 for 32 kHz and 40 kHz).