The researchers, working mainly in China and the United States, including at Harvard University, used an approach with cationic lipid-mediated delivery of Cas9-guide RNA complexes. The results of their study were published in late December in Nature.

Using a genome editing method, the group was able to reduce hearing loss in so-called “Beethoven” mice, which carry a mutation associated with deafness in both mice and humans, Nature reports. The technique called CRISPR–Cas9 makes it possible to knock out a mutant form of the Tmc1 gene, showing a potential new pathway for the treatment of other genetic causes of hearing loss.

A novel aspect of the research was its use of a positively charged fatty molecule that can cross the cell membrane. These particles were injected directly into the inner ears of the test mice so that they could be taken up by the hair cells.

This is important because, according to David Liu, a chemical biologist at the Broad Institute of MIT and Harvard in Cambridge, Massachusetts (USA) and a lead author of the study, the method could ultimately be used for gene therapy in people, after further testing.

Source: Nature; Gao X, et al. Treatment of autosomal dominant hearing loss by in vivo delivery of genome editing agents. Nature. 2018 Jan 11;553(7687):217-221.