Maturity-Onset Diabetes of the Young Type 3 (MODY 3): A Rare Presentation of Diabetes in Primary Care

Maturity-onset diabetes of the young (MODY) is a genetic form of diabetes with an autosomal dominant pattern of transmission characterized by dysfunction in pancreatic β-cells. MODY type 3 (MODY 3) is caused by heterozygous mutations in the hepatocyte nuclear factor 1-α (HNF1A) gene and is sensitive to treatment with sulfonylureas. This case report approaches the diagnostic journey of a 46-year-old woman who was initially misdiagnosed with type 2 diabetes. Despite adherence to pharmacological and lifestyle interventions, her glycemic control deteriorated. A comprehensive family history revealed a strong familial prevalence of diabetes. Genetic testing confirmed MODY 3, leading to the initiation of sulfonylurea therapy and subsequent glycemic control. This case emphasizes the diagnostic hurdles associated with MODY in primary care and the critical role of a genogram analysis in revealing familial patterns and giving strategies for personalized treatment.