SLC12A1 and type 2 diabetes mellitus: After removing unmatched genes, the results showed that two genes [including transferrin receptor (TFRC) and solute carrier family-11 member-2 (SLC11A2)] were both significantly down-regulated in T2DM samples when compared with normal samples, indicating that the downregulation of two key genes might cause IO and further induce the occurrence of T2DM (Fig. 7).