Clinical and Metabolic Features of Adult-Onset Diabetes Caused by ABCC8 Mutations

OBJECTIVE Gain-of-function ABCC8/sulfonylurea (SU) receptor 1 mutations cause neonatal diabetes mellitus (NDM) or late-onset diabetes in adult relatives. Given the effectiveness of SU treatment in ABCC8-NDM patients, we further characterized late-onset ABCC8-associated diabetes. RESEARCH DESIGN AND METHODS Seven adult subjects from three NDM families and one family with type 2 diabetes were studied. Insulin secretion and insulin sensitivity were assessed using clamp techniques. We screened 139 type 2 diabetic patients who were well controlled by SU for ABCC8 mutations. RESULTS ABCC8 mutation carriers exhibited glucose intolerance, frank diabetes, or insulin-requiring diabetes since diagnosis. HbA1c improved in five SU-treated patients. Insulin secretion capacity was impaired in three patients compared with adult control subjects but was restored after a 4-week SU trial in two patients. Cohort screening revealed four SU-treated patients with ABCC8 mutations, two of which are likely causal. CONCLUSIONS Although of rare occurrence, recognition of adult-onset ABCC8-associated diabetes may help in targeting patients for SU therapy.