In mature milk, the abundance of 25 proteins was increased, whereas those of 14 proteins were decreased in mothers with GDM when their BMI increased (Table S6), proteins calcitonin‐related polypeptide beta (CALCB), calsynthenin 3 (CLSTN3), and major histocompatibility complex, class II, DP alpha 1 (HLA‐DPA1). The gene discussed is HLA-DPA1; the disease is gestational diabetes.