Twenty-five patients were TPO-Abs positive at diabetes onset, and 21 of them (84%) developed thyroid dysfunction (20 hypothyroidism, 1 Graves’ disease), after a median follow-up of 5 years (range, 0–25), at a mean age of 35 ± 13 years (range, 15–72). The gene discussed is TPO; the disease is Graves disease.