Sensorineural hearing loss (SNHL) is the most prevalent genetic sensory defect in humans. It is estimated that globally 1:1000 children born have profound hearing loss. Non-syndromic SNHL accounts for approximately 70% of hereditary hearing loss. In addition, 80% of the non-syndromic SNHL cases have an autosomal recessive mode of inheritance (ARNSHL), also known as DFNB. To date, few dozens of genes and gene loci have been implicated in DFNB.
DFNB59 has been described in families in which affected individuals presented with either auditory neuropathy or hearing loss of cochlear origin. Auditory neuropathy is a type of sensorineural hearing impairment in which the auditory brainstem response (ABR) is absent or severely distorted while otoacoustic emissions (OAEs), which are low level sounds originating in the cochlea due to the mechanical activity of outer hair cells, are preserved. This suggests a primary lesion located in the inner hair cells, in the auditory nerve, or in the intervening synapse, but may also include damage to neuronal populations in the auditory pathway.