Endogenous hypercortisolism originates from an underlying tumor, most commonly an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma (Cushing disease [CD], 70%), followed by adrenal cortisol-secreting tumors (20%) and ectopic ACTH or, rarely, corticotropin releasing hormone (CRH)-secreting tumors (10%) (4, 5). The gene discussed is CRH; the disease is pituitary gland adenoma.