We selected TCF7L2 rs7903146 (intron variant) as the strongest T2DM associated genetic risk factor to date that is also associated with higher fasting and post-challenge glucose levels in Caucasians and another β-cell dysfunction associated T2DM risk variant (WFS1 rs1801214, missense) and also 11ΒHSD1 rs4844880 as a reported visceral obesity associated intron variant for further analysis from a prior gestational diabetes mellitus (GDM)-genetic study [20–29]. Here, TCF7L2 is linked to gestational diabetes.