Juvenile case with the coexistence of maturity‐onset diabetes of the young 1 and later‐onset latent autoimmune diabetes in youth

We present the case of a 12‐year‐old Japanese girl, who was positive for markers of both maturity‐onset diabetes of the young and latent autoimmune diabetes in youth. She was initially diagnosed with maturity‐onset diabetes of the young 1 based on the molecular analysis, and she later developed an autoimmune response, leading to β‐cell‐associated antibody‐positive diabetes. She was treated with incretin‐associated drugs and maintained adequate glycemic control. Pathophysiologically, there was an overlap between the two different types of diabetes, because the hyperglycemia and β‐cell stress seen in non‐autoimmune diabetes can cause β‐cell autoimmunity over time.