There are more than 300 genetic defects that have been found to prevent the hair cells in the human inner ear, the sensory cells of the ear as it were, from working properly. This can result in severe hearing impairment and even to complete hearing loss. A research team has now succeeded, for the very first time, to repair this defect in an animal model – by using a modified, non-pathogenic adeno-associated virus (Anc80L65), which is introduced into the ear by way of a “Trojan Horse” to deliver genes to restore the functionality of the damaged hair cells.