SLC11A1 and hyperinsulinemic hypoglycemia, familial, 4: Another argument in support of this hypothesis is that the expression of IRT1 (a low affinity Zn and Mn transporter; [48]) and NRAMP1 (the major high affinity Mn transporter; [49]) followed, in our experiments, a similar expression pattern (i.e. lower induction in response to Fe deficiency when S availability is scarce) (Figs 1D and 3A).