CRISPR/Cas9-mediated exon skipping to restore premature translation termination in a DFNB4 mouse model

SLC26A4 encodes pendrin, a crucial anion exchanger essential for maintaining hearing function. Mutations in SLC26A4, including the prevalent c.919-2 A > G splice-site mutation among East Asian individuals, can disrupt inner ear electrolyte balance, leading to syndromic and non-syndromic hearing loss, such as Pendred syndrome and DFNB4. To explore potential therapeutic strategies, we utilized CRISPR/Cas9-mediated exon skipping to create a Slc26a4∆E8+E9/∆E8+E9 mouse model. We assessed pendrin expression in the inner ear and evaluated vestibular and auditory functions. The Slc26a4∆E8+E9/∆E8+E9 mice demonstrated reframed pendrin in the inner ear and normal vestibular functions, contrasting with severely abnormal vestibular functions observed in the Slc26a4 c.919-2 A > G splicing mutation mouse model. However, despite these molecular achievements, hearing function did not show the expected improvement, consistent with observed pathology, including cochlear hair cell loss and elevated hearing thresholds. Consequently, our findings highlight the necessity for alternative genetic editing strategies to address hearing loss caused by the SLC26A4 c.919-2 A > G mutation.