Long‐term efficacy of the sodium‐glucose cotransporter 2 inhibitor ipragliflozin in a case of type A insulin resistance syndrome

Type A insulin resistance (IR) syndrome is a severe IR form caused by insulin receptor (INSR) gene defects. Antidiabetic drugs, including high-dose insulin and insulin-sensitizing agents, often fail to control associated hyperglycemia. Therapy with recombinant human insulin-like growth factor 1 can be more effective, but it is expensive. We report a case of type A IR syndrome with an in-frame INSR heterozygous deletion (DeltaLeu999) that was treated with a combination of conventional therapy and ipragliflozin, a sodium-glucose cotransporter 2 inhibitor. Treatment reduced hemoglobin A1c levels (10.0-7.5%) and induced weight loss (54.4-52.0 kg) within 2 months, and the effects were sustained for >3 years. Sodium-glucose cotransporter 2 inhibitors might be useful to normalize blood glucose in type A IR syndrome by reducing bodyweight and ameliorating glucotoxicity.