HNF1A and type 2 diabetes mellitus: According to previous studies on the effects of pathogenic HNF1A-MODY variants, pathogenic and MODY causal variants impair HNF1A activity, DNA binding, and localization (40% compared to WT HNF1A) (21, 32), whereas type 2 diabetes risk variants have an impact on HNF1A function ranging from 40% -60% compared to WT (30, 31, 33).