A Study in Subjects With Otoferlin Mutation-related Hearing Loss Using RNA Base-eDiting Therapy (SOUND)

Inclusion Criteria: Male or females between 1 and 16 years of age at the time the subject/parent/legal guardian signs the informed consent form. Willing to adhere to the protocol as evidenced by written informed consent or parental permission and subject assent. Molecular diagnosis of biallelic mutations in the OTOF gene with at least one mutation being p.Q829X through collected blood samples at screening; Based on auditory brainstem response (ABR), clinically diagnosed sensorineural hearing loss (SNHL) with the following hearing thresholds: severe (65 dB ≤ hearing threshold < 80 dB) or profound (80 dB ≤ hearing threshold < 95 dB) or complete (hearing threshold ≥ 95 dB) hearing loss in both ears. Acceptable hematology, clinical chemistry, and urine laboratory parameters. Exclusion Criteria: Pre-existing other hearing-loss conditions that would preclude the planned surgery or interfere with the interpretation of study endpoints or complications of surgery. Presence of cochlear implants in the study ear. Complicating systemic diseases or clinically significant abnormal baseline laboratory values. Complicating systemic diseases would include those in which the disease itself, or the treatment for the disease, can alter hearing function. Prior participation in clinical study with an investigational drug within the past six months. Prior gene therapy treatments. Any condition which leads the investigator to believe that the participant cannot comply with the protocol requirements or that may place the participant at an unacceptable risk for participation.