HNF1A and type 2 diabetes mellitus: FPG was lower for GCK‐MODY patients compared to those with HNF1A‐MODY (SMD −0.57 [95% CI −0.90, −0.23] mmol/l, p < .001, n = 18; I2 = 82%, Ph <.01), which was consistent in the subgroup analysis, and we found a similar result for GCK‐MODY patients compared to type 2 diabetes patients (overall SMD −0.44 [95% CI −0.69, −0.19] mmol/l, p < .001, n = 9; I2 = 69%, Ph <.01), though this difference was statistically significant only in the subgroup that contained all family members.