Pituitary MRI did not identify a pituitary adenoma, while a bilateral inferior petrosal sinus sampling (BIPSS) performed in the off-phase was indicative of central ACTH production because of a strong ACTH increase after corticotrophin release hormone (CRH) injection (100 μg i.v.)in the right petrosal sinus and a central to peripheral gradient of 7.3 at 15′ (Fig. 1a). The gene discussed is POMC; the disease is pituitary gland adenoma.