MTNR1B and type 2 diabetes mellitus: Our previous study in a Chinese Han population confirmed the associations of T2D with GWAS-validated SNPs in or near WFS1, CDKAL1, CDKN2A/2B, CDC123/CAMK1D, HHEX, TCF7L2, KCNQ1, and MTNR1B, all of which were essential in β-cell function.[9] However, many genetic variants have been revealed by GWAS in Caucasians that could not be replicated in Chinese Han or other East Asian populations, partly due to the heterogeneity of T2D.