In the current retrospective cohort analysis of women who have recently experienced GDM, we found that low serum creatinine levels at 10–14 weeks gestation were positively associated with an increased risk of postpartum AGM incidence, regardless of other major risk factors such as age, BMI, gestational weight increase, family history of T2DM, previous history of GDM, insulin use and glucose level. The gene discussed is INS; the disease is autosomal agammaglobulinemia.