Use of a Sodium-Glucose Cotransporter 2 Inhibitor, Empagliflozin, in a Patient with Rabson-Mendenhall Syndrome.

Introduction: Among the insulin resistance syndromes that lead to diabetes mellitus in young people, Rabson-Mendenhall syndrome (RMS; OMIM # 262190) is an autosomal recessive inherited disease caused by an insulin receptor mutation (INSR; 147,670). Due to the rarity and complexity of the disease, we have few therapeutic alternatives other than insulin with clinical studies with robust evidence. Some reports suggest the adjunct use of metreleptin, metformin, and pioglitazone with improved glycemic control, however, with results still unsatisfactory for the desirable glycemic targets for this age group.

Case Presentation: We report a case of an 11-year-old patient who was diagnosed with RMS at 6 years of age, confirmed through genetic sequencing, with unsatisfactory glycemic control despite the use of >5 IU/kg/day of insulin, pioglitazone, and metformin. To optimize therapy, we used empagliflozin (SGLT2i) to correct hyperglycemia. With the use of the drug, we obtained a decrease of almost 3% in the value of glycated hemoglobin (HbA1c) and about 30% reduction in the total daily dose of insulin.

Discussion/conclusion: In this specific case, considering the glycosuric effects independent of the functionality of insulin receptors (which in this case had partial activity due to the INSR gene mutation), an improvement in glycemic control was obtained, with optimization of HbA1c without documented or reported adverse effects. From this isolated case and understanding the pharmacokinetics of this drug class, the question remains whether it would be possible to use this treatment in other situations of SIR where we also have few therapeutic perspectives.