HSD11B2 catalyzes the conversion of cortisol to the inactive metabolite cortisone. The protein modulates intracellular glucocorticoid levels, thus protecting the nonselective mineralocorticoid receptor from occupation by glucocorticoids.Defects in HSD11B2 are the cause of apparent mineralocorticoid excess (AME). AME is a potentially fatal disease characterized by severe juvenile low-renin hypertension, sodium retention, hypokalemia and low levels of aldosterone. It often leads to nephrocalcinosis.