Pathogenic variation of SLC26A 4 gene causes both Pendred syndrome (PDS) and non-syndromic enlarged vestibular aqueduct (NSEVA/DFNB4), two autosomal recessive disorders. The former accounts for approximately 6% of human genetic hearing loss, making it the second most common form of syndromic deafness after Usher syndrome, while the latter is the most common radiological malformation associated with childhood sensorineural hear...