Genes et al. evaluated 104 patients with diabetes aged older than 16 years: 24 with HNF4A-MODY, 40 with T1D, and 40 with T2D; their mean age was 32 years, with fasting glucose levels > 200 mg/dL and HbA1c > 10%. The gene discussed is HNF4A; the disease is diabetes mellitus.