SLC26A3 is a transmembrane glycoprotein that functions as a sulfate transporter. It is localized to the mucosa of the lower intestinal tract, particularly to the apical membrane of columnar epithelium and some goblet cells. Mutations in this gene have been associated with congenital chloride diarrhoea , a treatable disease.Its expression, which appeared to be limited to the mucosa of normal colon, was significantly decreased in adenomas and adenocarcinomas of the colon and was downregulated early in tumorigenesis.All exon/intron boundaries conformed to the GT/AG rule. Genomic sequencing of a BAC clone revealed the presence of another, highly homologous gene 3-prime of the CLD gene, with a similar genomic structure, identified as the Pendred syndrome gene (SLC26A4).