**4.6 Syndrome of Apparent Mineralocorticoid Excess (AME)**

This autosomal recessive syndrome is characterised by hypertension, hypokalemia, metabolic alkalosis, with suppressed renin and aldosterone levels. Hypercalciuria and nephrocalcinosis may occur. Typically, an affected child will have polyuria and polydipsia, low birth weight and faltering growth. The molecular basis for this syndrome is secondary to mutations in the *HSD11B2* gene encoding the enzyme 11-betahydroxysteroid dehydrogenase 2 (Wilson, et al., 1995). This enzyme normally inactivates cortisol to cortisone, preventing overstimulation of the mineralocorticoid receptor (MR). Mutations lead to an excess of cortisol which is able to have a mineralocorticoid–like affect and stimulate sodium retention, volume expansion and renin and aldosterone suppression.

This syndrome may be mimicked by licorice ingestion (Walker &Edwards, 1994). Licorice contains glycyrrhizinic acid, which inhibits 11-beta-HSD2. Carbenoxolone also inhibits this enzyme. The treatment of choice for AME is a mineralocorticoid receptor blocker such as spironolactone or epleronone.
