Three members across two generations of a family were diagnosed with diabetes before age 25 years. They are all non-obese, never developed ketosis even when off treatment, have no islet autoantibodies, and are controlled on very small doses of glimepiride rather than insulin. Which genetic subtype best fits this pattern and its preferred therapy?

• A MODY type 1 (HNF4A), best managed with basal-bolus insulin
• B MODY type 3 (HNF1A), highly responsive to low-dose sulfonylureas ✓
• C MODY type 2 (GCK), requiring lifelong intensive insulin
• D Type 1 diabetes, slow-onset variant, best treated with pramlintide

Explanation

Autosomal dominant early-onset non-ketotic diabetes with preserved insulin secretion defines maturity-onset diabetes of the young. HNF1A-MODY (MODY 3) is the commonest subtype and shows marked sensitivity to sulfonylureas, often achieving control on doses far lower than those used in type 2 diabetes. GCK-MODY typically needs no pharmacotherapy except in pregnancy, and HNF4A-MODY responds well to sulfonylureas too.

Reference: Williams Textbook of Endocrinology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.