It has been described that mutations leading to X-linked deafness type 3 (DFN3) syndrome not only affect the POU3F4 coding sequence [16] but also upstream non-coding regions, since many human patients displaying sensorineural hearing loss contain microdeletions in a region 1 Mb 5′ upstream of the POU3F4 gene. Here, POU3F4 is linked to sensorineural hearing loss disorder.