['To report the long-term follow-up of three nonpancreatectomized patients with persistent hyperinsulinemic hypoglycemia of infancy due to mutations in the ABCC8 gene.', 'Oral glucose tolerance test (OGTT) and venous 24-h glucose-insulin profile were performed yearly from adolescence.', 'Patient 1 (now aged 31 years) developed insulin-dependent diabetes at the age of 25 years. In patient 2 (now aged 17 years), impaired fasting glucose and a diabetic OGTT response with normal A1C values have been observed since the age of 10 years. In patient 3 (now aged 24 years), intolerant OGTT response and hyperglycemic episodes with normal A1C have been observed since the age of 16 years. All patients presented relatively low insulin levels during hyperglycemia, normal BMI, and negative autoantibodies (GAD antibody, insulinoma-associated protein 2, and islet cell antibody).'] Are glucose intolerance and diabetes observed in the long-term follow-up of nonpancreatectomized patients with persistent hyperinsulinemic hypoglycemia of infancy due to mutations in the ABCC8 gene?