Apparent mineralocorticoid excess syndromes
A number of hereditary abnormalities affecting the distal tubule mimic mineralocorticoid excess:
Loss of the ability to down-regulate the Na+ channel in the cortical collecting duct (Liddle's syndrome).
A defect leading to inactivation of an enzyme associated with the aldosterone receptor, resulting in the receptor being activated by cortisol as well as aldosterone.
These conditions are characterised by a very low aldosterone level.