A correct genetic diagnosis of MODY may alter the therapeutic approach: patients with glucokinase (GCK) MODY usually do not require pharmacological treatment, and those with either hepatocyte nuclear factor 4-α (HNF4A) or hepatocyte nuclear factor 4-α (HNF1A) MODY are very sensitive to sulfonylurea [8]. The gene discussed is HNF4A; the disease is MODY.