SLC26A7 is a multifunctional anion transporter that primarily mediates transmembrane transport of chloride, sulfate, oxalate, bromide, iodide, nitrate, thiocyanate, and bicarbonate ions 1. The protein functions as both an anion channel and exhibits chloride-bicarbonate exchanger activity 1. SLC26A7 plays a critical role in thyroid hormone biosynthesis through iodide transport, with homozygous loss-of-function mutations causing goitrous congenital hypothyroidism 2. Mouse studies demonstrate that SLC26A7 impacts thyroid function more strongly than the related transporter SLC26A4, with Slc26a7-deficient mice showing severe hypothyroidism and growth failure that is partially corrected by iodine supplementation 3. In the kidney, SLC26A7 localizes to intercalated cells of collecting ducts and shows dynamic subcellular trafficking, residing in endosomes under normal conditions but translocating to the basolateral membrane during hypertonicity and potassium depletion 4. The protein is also expressed in gastric parietal cells and contributes to bicarbonate transport during tooth enamel maturation 5. Population genetic analysis indicates SLC26A7 mutations contribute to autosomal recessive congenital hypothyroidism with a carrier frequency of 0.144% globally 6.