Relapsing 6q24-related transient neonatal diabetes mellitus successfully treated with a dipeptidyl peptidase-4 inhibitor: a case report.

The most common form of transient neonatal diabetes mellitus (TNDM) is 6q24-related TNDM. Patients are treated with insulin during the neonatal period until spontaneous remission. However, diabetes often recurs in adolescence, and there is no standard therapy for patients with a relapse. A paternal duplication at the 6q24 critical region spanning the pleiomorphic adenoma gene-like 1 PLAGL1 gene was found in a Japanese patient with TNDM relapse. The patient was treated with a dipeptidyl peptidase-4 (DPP4) inhibitor, alogliptin, at a dose of 25 mg per day. Immediately after treatment initiation, his hemoglobin A1c (HbA1c) levels dropped from 7.0-7.5% (52-58 mmol/mol) to 6.0-6.5% (41-47 mmol/mol) and remained stable for over a year. We reported the successful treatment of relapsed 6q24-related TNDM with a DPP4 inhibitor. Although insulin has been the conventional treatment for such patients, treatments targeting the GLP1 pathway can be a useful alternative because these patients retain the β cell mass and responsiveness through G protein-coupled pathways.