Open-label Study of SKY-GJB2 in Pediatric Subjects With GJB2-mediated Hearing Loss

Inclusion Criteria: * Male or female aged 9 months to 7 years at the time of gene therapy administration * Subjects must have at least two (biallelic) pathogenic or likely pathogenic variants in the GJB2 gene * Bilateral sensorineural hearing loss as assessed by ABR. Hearing loss at ≥85 dB HL for at least one of the frequencies (500-4000 Hz) in the study treatment ear. * Subject's parent(s)/guardian(s) provide informed consent before the initiation of study-related procedures. * Subject is able and willing to comply (or provide assent if old enough) will all study requirements. Exclusion Criteria: * Subject has non-GJB2 mediated hearing loss including genetic, syndromic, or non-syndromic hearing loss that is not associated with GJB2 mutations. * Subject has autosomal dominant nonsyndromic hearing loss due to GJB2 mutation. * No response on ABR testing. * Bilateral Cochlear Implants.