Gliclazide challenge testing as an alternative diagnostic tool for hepatocyte nuclear factor-1-alpha maturity onset diabetes of the young

Young patients with atypical diabetes (negative autoantibodies, preserved C-peptide, recurrent hypoglycaemia on insulin) should prompt consideration of monogenic diabetes, and the Exeter maturity-onset diabetes of the young calculator is a valuable screening tool for clinicians.A gliclazide challenge test with serial C-peptide measurement can provide a simple, functional assessment of sulfonylurea sensitivity, supporting the diagnosis of maturity-onset diabetes of the young, in centres where genetic testing is limited or delayed.Early recognition of maturity-onset diabetes of the young allows safe transition from insulin to sulfonylureas, preventing years of unnecessary injections, reducing hypoglycaemic episodes, and improving long-term quality of life.