After a laboratorial confirmation of endogenous Cushing’s syndrome, the subsequent diagnostic approach is to classify the syndrome according to the plasma ACTH levels: ACTH-dependent (ACTH higher than 20 pg/mL: CD vs. EAS) or ACTH-independent (ACTH less than 10 pg/mL: adenomas, carcinomas, or adrenal hyperplasia) Cushing’s syndrome. This evidence concerns the gene POMC and Cushing syndrome.