Finally, we analyzed the expression of the SLC11A2/DMT1 gene (SoLute Carrier Family 11, member 2/Divalent Metal Transporter 1) encoding a key carrier protein involved in iron homeostasis and absorption through cell membranes [31]; altered DMT1 expression/function is associated with unbalanced responses to iron overload/deficiency [32]. This evidence concerns the gene SLC11A2 and hyperinsulinemic hypoglycemia, familial, 4.