Syndrome, Conn: Overproduction of the hormone aldosterone (pronounced al-do-ster-one) by a tumor that contains tissue resembling that normally present in the outer portion (cortex) of the adrenal gland. The excess aldosterone results in a potassium level (hypokalemia), underacidity of the body (alkalosis), muscle weakness, excessive thirst (polydipsia), excessive urination (polyuria), and high blood pressure (hypertension).

Also called primary aldosteronism or primary hyperaldosteronism. The syndrome is named after the American physician Jerome W. Conn (1907-1981) who almost singlehandedly defined the syndrome of aldosterone excess.