Paradoxical glycemia in an adult with ABCC8 p.Arg1352His: a case of maturity-onset diabetes of the young, type 12

Adults presenting with atypical diabetes, especially those with unexplained hypoglycemia, often pose a significant diagnostic challenge. Here, we describe a 53-year-old woman initially treated for type 2 diabetes who later developed recurrent hypoglycemia, with increased severity after fundoplication surgery, despite medication cessation, exhibiting persistent, and paradoxical glycemic variability. Detailed metabolic investigation ultimately revealed a heterozygous ABCC8 p.Arg1352His pathogenic variant, confirming a diagnosis of maturity-onset diabetes of the young, type 12. This case underscores the crucial role of genetic testing in diagnosing complex, monogenic glycemic disorders and illustrates the unique management complexities of a dual hyperglycemic–hypoglycemic phenotype, emphasizing the need for heightened clinical suspicion of an underlying genetic disorder potentially exacerbated by upper gastrointestinal surgery.