A 13-year-old boy presents with polyuria, polydipsia, and nocturia over 2 months with 4-kg weight loss. Vital signs show BP 118/76 mmHg, HR 92 bpm, RR 18/min, temperature 37.2°C, and SpO2 98% on room air. Fasting glucose is 312 mg/dL with positive anti-glutamic acid decarboxylase antibodies. Urinalysis shows no ketones. He takes no chronic medications. Which of the following is the most likely diagnosis?

1. A)Type 1 diabetes mellitusGABARITO
2. B)Diabetes insipidus
3. C)Cushing syndrome
4. D)Maturity onset diabetes of the young
5. E)Type 2 diabetes mellitus