It regulates anions such as Cl−, HCO3−, and I− depending on the sites of its expression.[30] In the inner ear, it is expressed in the apical membrane of transitional cells (saccule, utricle, and ampullae), epithelium of the endolymphatic sac and duct, and in a multitude of cell types in the cochlea.[31] Decreased bicarbonate secretions can reduce fluid resorption in the endolymphatic sac resulting in HL and cochlear enlargement.[32] Variants in the pendrin gene lead to autosomal recessive non‐syndromic HL (DFNB4) with enlarged vestibular aqueduct (EVA). Here, SLC26A4 is linked to autosomal recessive nonsyndromic hearing loss 4.