Another less common form of diabetes is maturity-onset diabetes of the young (MODY), which is a monogenic diabetes that leads to a defect in β cell insulin secretion.1-3 Patients with MODY may be misdiagnosed with either type 1 diabetes (T1D) or type 2 diabetes (T2D) depending on age and presentation (Table). 

MODY is categorized into 14 known subtypes based on the genes affected. The 2 most common are MODY 2 and MODY 3, which result from defects in the glucokinase and hepatocyte nuclear factor-1α genes, respectively.1-3 Typically diagnosed when they are <25 years of age, patients with MODY lack insulin resistance and overweight/obesity commonly associated with T2D and autoantibodies associated with T1D. 

Patients with MODY have a strong family history of diabetes in an autosomal-dominant pattern (more than 2 generations). Genetic testing confirms the diagnosis.1,2 Lifestyle modification is appropriate for both MODY 2 and 3, and patients with MODY 3 respond well to treatment with sulfonylurea agents. Progression to insulin dependence is infrequent in patients with MODY.2,3

Click to read about latent autoimmune diabetes in adults, another uncommon form of diabetes.


  1. Carlsson A, Shepherd M, Ellard S, et al. Absence of islet autoantibodies and modestly raised glucose values at diabetes diagnosis should lead to testing for MODY: lessons from a 5-year pediatric Swedish national cohort study. Diabetes Care.  2020;43(1):82-89.
  2. Delvecchio M, Salzano G, Bonura C, et al. Can HbA1c combined with fasting plasma glucose help to assess priority for GCK-MODY vs HNF1A-MODY genetic testing? Acta Diabetol. 2018;55(9):981-983.
  3. Urakami T. Maturity-onset diabetes of the young (MODY): current perspectives on diagnosis and treatmentDiabetes Metab Syndr Obes. 2019;12:1047-1056.