It was also found that patients in the T2D group had a higher BMI, but there were no significant differences among those in the GCK-MODY, HNF1A-MODY, and T1D groups [26.9 ± 4.69 kg/m2 (T2D) vs. 19.3 ± 4.04 kg/m2 (GCK-MODY), 20.3 ± 3.43 kg/m2 (T1D), and 20.7 ± 2.92 kg/m2 (HNF1A-MODY)]. This evidence concerns the gene GCK and type 2 diabetes mellitus.