MTNR1B and type 1 diabetes mellitus: For example, certain T2D susceptibility loci, such as the PPARG Pro12Ala variant, MTNR1B, HNF1A, GLIS3, 6q22.32, and novel loci near the MHC, which harbour HLA class II genes, are associated with approximately half of the risk for developing T1D (Eftychi et al., 2004; Raj et al., 2009; Andersen et al., 2014; Mahajan et al., 2014).