Which condition is characterized by an excess production of cortisol?

Cushing's syndrome is characterized by an excess production of cortisol, which is a steroid hormone produced by the adrenal glands. This condition can result from various causes, including adrenal tumors, pituitary adenomas that increase adrenocorticotropic hormone (ACTH) production, or ectopic ACTH production from tumors elsewhere in the body. The elevated levels of cortisol lead to distinctive clinical features such as obesity with a central distribution of fat, a rounded face often referred to as a "moon face," skin changes (like easy bruising and purple striae), muscle weakness, and hypertension.

Understanding the nature of Cushing's syndrome is critical because it not only affects metabolism but also has significant implications for multiple body systems, resulting in complications like increased risk for infections, osteoporosis, and cardiovascular disease. The other conditions listed do not involve excess cortisol production: hypoparathyroidism primarily affects calcium and phosphorus homeostasis, Addison's disease is associated with insufficient cortisol production, and Graves' disease is an autoimmune hyperthyroid condition.