Pendred syndrome is thought to account for about 10% of hereditary hearing loss and is one of the most common forms of syndromic deafness.[5] In 1997, it was reported that the double allele mutation of SLC26A4 gene (also known as Pendred syndrome gene) could explain the cause of this syndrome at the molecular level.[6] The gene encodes pendrin, a multifunctional anion transporter. This evidence concerns the gene SLC26A4 and deafness.