Post-hoc analysis revealed significant differences in mean GCR rise between the T2DM and MODY forms of diabetes (p = 0.02 and p = 0.003 for HNF1-MODY and GCK-MODY, respectively); however, no difference between the HNF1A-MODY and GCK-MODY groups were observed (p = 0.72). This evidence concerns the gene GCK and type 2 diabetes mellitus.