Genome editing restores hearing in mice

For over half of children born with hearing loss, a single genetic abnormality is to blame. Scientists have been searching for ways to restore hearing via gene editing. A research team led by Dr. Zheng-Yi Chen at Mass Eye and Ear in Boston developed a gene editing approach that works in adult mice, with a fully mature inner ear. Their study appeared on July 10, 2024, in Science Translational Medicine. The scientists created a mouse model with a specific mutation in the microRNA-96 (MIR96) gene, which regulates gene activity in the ear’s tiny hair cells. Mice with the mutation lose their hair cells and develop complete hearing loss in high frequencies. Researchers found that injecting an optimized CRISPR-Cas9 system into the inner ear of adult mice led to partial restoration of hearing, marking a significant step towards human genetic hearing loss treatments.