A 5-year-old boy presents with fasting plasma glucose of 128 mg/dL and a 2-hour post-glucose level of 152 mg/dL on two separate occasions. He is not obese. His father and paternal grandfather had diabetes diagnosed before age 25 years, none requiring insulin. HbA1c is 6.4%. Which diagnosis is most likely?

• A Type 1 diabetes mellitus
• B Type 2 diabetes mellitus
• C Neonatal diabetes mellitus
• D Maturity-onset diabetes of the young (MODY) ✓

Explanation

MODY is a monogenic autosomal dominant diabetes presenting before age 25 years, non-obese, non-insulin requiring at diagnosis, with a strong vertical family history. The classic triad fits this boy perfectly. Type 1 would require insulin and have autoantibodies. Type 2 in a non-obese 5-year-old with this family pattern is less likely. Neonatal diabetes presents before 6 months of age. MODY (especially GCK-MODY or HNF1A-MODY) is the best fit.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.