What condition is characterized by elevated levels of aldosterone?

Conn syndrome, also known as primary hyperaldosteronism, is characterized by elevated levels of aldosterone due to an adrenal gland abnormality, often an adrenal adenoma. This condition leads to increased sodium retention, potassium excretion, and water retention, resulting in hypertension and hypokalemia. The primary issue in Conn syndrome is the overproduction of aldosterone independent of the regulatory mechanisms typically influencing its secretion, such as the renin-angiotensin system.

In contrast, Cushing's syndrome involves excess cortisol and may sometimes cause secondary increases in aldosterone, but it is primarily related to glucocorticoid excess. Addison's disease, on the other hand, is characterized by insufficient adrenal hormone production, leading to low levels of aldosterone, among other hormones. Pheochromocytoma is a tumor that secretes catecholamines (like adrenaline) and does not directly involve aldosterone secretion. Thus, Conn syndrome is the correct answer when identifying a condition specifically associated with elevated aldosterone levels.