Disruption of the potassium channel regulatory subunit Kcne2 causes iron-deficient anemia

Iron homeostasis is a dynamic process that is tightly controlled to balance iron uptake, storage and export. Reduction of dietary iron from the ferric to the ferrous form is required for uptake by solute carrier family 11 (proton-coupled divalent metal ion transporters) member 2 (Slc11a2) into the enterocytes. Both processes are proton dependent, and have led to the suggestion of the importance of acidic gastric pH for the absorption of dietary iron. Kcne2, in combination with Kcnq1, form a gastric potassium channel essential for gastric acidification. Deficiency of either Kcne2 or Kcnq1 results in achlorhydia, gastric hyperplasia and neoplasia, but the impact on iron absorption has not been investigated. Here we report that Kcne2 deficient mice, in addition to the previously reported phenotypes, also present with iron-deficient anemia. Interestingly impaired function of KCNQ1 results in iron deficient anemia in Jervell and Lange-Nielsen syndrome patients. We speculate that impaired function of KCNE2 could result in the same clinical phenotype.