The primary site for absorption of dietary iron is the duodenum. Ferrous iron (Fe2+) is taken up from the gut lumen across the apical membranes of enterocytes and released into the portal vein circulation across basolateral membranes. The human gene SLC11A2 encodes the divalent cation transporter DCT1 (NRAMP2, Natural resistance-associated macrophage protein 2). DCT1 resides on the apical membrane of enterocytes and mediates the uptake of many metal ions, particularly ferrous iron, into these cells. Defects in SLC11A2 can cause hypochromic microcytic anemia, with iron overload 1 (AHMIO1; MIM:206100), a blood disorder characterised by high serum iron, large hepatic iron deposition, abnormal haemoglobin content in erythrocytes which are reduced in size and absence of sideroblasts and stainable bone marrow iron store.
Mutations in SLC11A2 that cause AHMIO1 include E399D, 310delCTT, R416C, V114del and G212V (Mims et al. 2005, Iolascon et al. 2006, Beaumont et al. 2006).