Karolinska Institutet and Chinese hospitals achieved a medical milestone by reversing congenital deafness through gene therapy. Ten patients with OTOF gene mutations received a single injection of a synthetic adeno-associated virus (AAV) delivering a functional OTOF gene. Published in *Nature Medicine*, the trial showed immediate results: most participants regained detectable hearing within a month, with profound improvements in children aged 5-8.

A 7-year-old girl regained near-normal hearing, enabling daily conversations within four months. Otivia Therapeutics Inc., the therapy’s developer, reported all patients tolerated the treatment safely, with only mild neutrophil reduction as a side effect. This marks the first successful gene therapy for OTOF-related deafness in both children and adults, offering hope for irreversible hearing loss. Researchers plan to expand trials to other genetic causes like GJB2 and TMC1, which affect broader populations.

Collaborations between Swedish and Chinese institutions, funded by Chinese research grants and Otivia, highlight global efforts to combat genetic hearing loss. The study’s success underscores gene therapy’s potential to transform lives, with follow-ups tracking long-term efficacy.