MODY (Maturity-Onset Diabetes of the Young) is a monogenic form of diabetes, typically presenting before age 25, with an autosomal dominant inheritance pattern.

• Key Features:
  • Early onset: Diagnosis often occurs before age 25, but symptoms may be mild, leading to delayed diagnosis.
  • Non-insulin-dependent: Initially managed without insulin, though some subtypes may require it later.
  • Strong family history: Autosomal dominant inheritance is common, with affected family members across generations.

• Subtypes (based on genetic mutations):
  • HNF1A (MODY 3): Most common; associated with high sensitivity to sulfonylureas.
  • HNF4A (MODY 1): Often presents with low birth weight and liver dysfunction.
  • GCK (MODY 2): Mild hyperglycemia; often no treatment needed.
  • Other subtypes (e.g., PDX1, HNF1B): Less common; may present with renal or liver abnormalities.

• Diagnosis:
  • Genetic testing is confirmatory; clinical criteria include early-onset diabetes, strong family history, and absence of autoimmunity (negative islet autoantibodies).

• Management:
  • Subtype-specific: E.g., sulfonylureas for HNF1A, diet/exercise for GCK-MODY.
  • Avoid insulin if possible (except in severe cases or pregnancy).

• Rationale: MODY is distinct from type 1/2 diabetes due to its genetic basis and unique treatment responses. Early diagnosis prevents unnecessary insulin use and optimizes therapy.