Slc26a4, which encodes pendrin, is a member of the SLC26A transporter family. It transports various ions like bicarbonate, chloride, iodine, and oxalate, and is involved in maintaining hearing function, renal function, blood pressure, and hormone and pH regulation. It is expressed in multiple tissues including the airway epithelium, kidney, thyroid, and tumors [3].

Mutations in Slc26a4 are a common cause of deafness, responsible for Pendred syndrome and non-syndromic enlarged vestibular aqueduct (EVA). In China, the ratio of EVA in the deaf population was at least 11%, with a distinct mutational spectrum among ethnicities and regions. Most variants cause pendrin retention in the intracellular region and significantly reduce its transport capability [1]. Also, Slc26a4-related hearing loss shows different phenotypes depending on the genotype. For example, two mutant alleles are correlated with bilateral EVA and Pendred syndrome, while unilateral EVA and non-syndromic EVA may be associated with one or zero mutant alleles [2].

In conclusion, Slc26a4 is crucial for normal inner ear function, and its mutations can lead to various hearing-related disorders. Understanding the role of Slc26a4 through studies on its mutations in human populations helps in genetic diagnosis, counseling, prenatal testing, and pre-implantation diagnosis for EVA families [1].