A 19-year-old lean woman is evaluated for mild fasting hyperglycaemia detected on a college health check. Her mother and maternal grandfather were diagnosed with diabetes before age 30 and are not obese; neither ever developed ketoacidosis. Anti-GAD antibodies are negative, C-peptide is preserved, and she has no acanthosis nigricans. Which statement about her most likely condition is correct?
- A It results from mutations in the hepatocyte nuclear factor genes and often responds to low-dose sulfonylureas ✓
- B It is caused by autoimmunity against beta cells and requires lifelong insulin from diagnosis
- C It results from severe insulin resistance and requires high-dose thiazolidinediones
- D It is secondary to pancreatic exocrine destruction and requires pancreatic enzyme replacement
Correct answer: A. It results from mutations in the hepatocyte nuclear factor genes and often responds to low-dose sulfonylureas
Explanation
Autosomal dominant transmission across generations, young onset, absence of obesity, absent autoimmune markers, and preserved C-peptide define maturity-onset diabetes of the young. HNF1A mutation (formerly MODY type 3) is the commonest form and characteristically shows marked sensitivity to low-dose sulfonylureas, which can be used instead of insulin. Type 1 diabetes would show positive antibodies and proneness to ketosis, and severe insulin resistance would present with obesity and acanthosis nigricans.
Reference: Williams Textbook of Endocrinology, 14th ed.
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Written and medically reviewed by the StethoPrep medical team.