Genetic testing is the gold standard for diagnosis of GCK‐MODY and is cost‐effective in clinically selected patients.25 Selection techniques such as the MODY probability calculator can assist with the identification of those patients most likely to have a GCK mutation.8 In this study, GCK analysis was performed only for the patients with fasting blood glucose between 99 and 145 mg/dl (5·5–8·0 mmol/l), HbA1c levels ≤7·5% (58·5 mmol/mol) and a MODY calculator score ≥75%. This evidence concerns the gene GCK and MODY.