Mifepristone is a competitive GR and progesterone receptor (PR) antagonist approved by the US Food and Drug Administration (FDA) in 2012 to control hyperglycemia secondary to hypercortisolism in patients with endogenous hypercortisolism (Cushing syndrome) who have type 2 diabetes mellitus or glucose intolerance and have failed surgery or are not candidates for surgery. The gene discussed is NR3C1; the disease is adrenal gland hyperfunction.