Hearing loss is one of the most common conditions in children. There are several gene mutations that have been implicated in hearing loss, but currently, there are no specific treatments for hereditary hearing loss. Hearing aids can help but these do not solve the problem at the root cause which is at the molecular level.
A study has been published in Science Translational Medicine, whereby researchers repaired a single base mutation that causes deafness in Baringo mice using CRISPR base editing. Base editing is whereby a single base is edited. Due to this characteristic, it is beneficial to use CRISPR base editing to repair point mutations that cause diseases.
A point mutation in the transmembrane channel-like 1 gene (TMC1) causes deafness in the Baringo mice. The TMC1 gene encodes a protein that makes up the mechanosensitive ion channels in the cells of the ears and thus it is vital for normal hearing. In this study, the Baringo mice that were treated with the CRISPR base editing had their hair cell function repaired. Furthermore, these mice were sensitive to low-frequency sounds even at 4 weeks of age (Baringo mice are completely deaf by 4 weeks of age). Therefore, suggesting that the base editing had transiently restored some of the auditory function in the CRISPR edited Baringo mice.
This study provides an insight into how CRISPR base editing could be used to repair one of the many mutations that cause hearing loss, and if the technology can be further refined, it may become a conventional treatment for hearing loss one day, but there is still a long way to go.