Researchers found mutations in a master-switch protein called Epithelial Splicing Regulatory Protein 1 in individuals with a type of congenital hearing loss. In general, what connects most of the unexplained hearing-loss cases is that protein building in the cochlea during development goes awry. The cochlea has the all-important job of transforming mechanical energy in the form of sound waves into electrical signals that run along auditory nerves to the brain.