Nature communicationsDec 6, 2025

RNA base editing that avoids CRISPR helps restore hearing in mice with a mutation causing early stop signals in the Otof gene

CRISPR Gene Editing Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Jun 27, 2026

Abstract

Essence

A CRISPR-free RNA base editor restored otoferlin expression and improved hearing in mice with a specific Otof nonsense mutation.

Evidence

Preclinical mouse gene-editing study delivered the RESTART v3 RNA base editor into cochleae of Otof c.1315 C > T deaf mice and measured otoferlin, hearing, and auditory startle responses.

Caveat

The result is limited to a mouse model of one Otof nonsense mutation and does not yet show human safety or efficacy.

Simplified

The gene therapy achieved by AAV-mediated otoferlin-overexpression is an effective therapeutic strategy for congenital deafness. However, achieving its physiological and endogenous patterns of expression remains challenging. Here, we generate the homologous mutation Otof c.1315 C > T (p.R439), equivalent to OTOF c.1273 C > T (p.R425) found in humans with profound deafness, to create a nonsense mutation-induced deaf mouse model. We then deliver the 'RESTART v3' system, which is a CRISPR-free RNA base editor for nonsense mutation suppression, into the cochlea of the mice. We achieve physiological otoferlin expression, and the edited premature termination codon is reverse-mutated to the original amino acid. We observe significant hearing restoration and enhancement of the behavioral auditory startle reflex. Thus, our study presents a successful RNA editing strategy to significantly restore hereditary deafness in mice carrying the specific Otof nonsense mutation, which holds great promise for future clinical translation.