Consistent with our observations in T2D subjects, RBC from 25 weeks old db/db mice exhibited lower cellular Mg2+ content (2.3 ± 0.2 mmol/kg Hb) than RBC of db/+ control mice of similar age (4.4 ± 0.5, n = 3; p < 0.03). This evidence concerns the gene GSTM1 and type 2 diabetes mellitus.