Liddle's syndrome

Liddle's syndrome, also written Liddle syndrome, is an extremely rare genetic disorder inherited in an autosomal dominant pattern. It causes early and often severe high blood pressure together with low blood potassium, metabolic alkalosis and low plasma renin activity, while aldosterone levels are normal to low. The cause is a mutation that stops the epithelial sodium channel in the kidney from being broken down normally, so the channel stays active and the kidney reabsorbs too much sodium and loses potassium, which mimics an excess of aldosterone. Children are often free of symptoms, and the condition may first be noticed as unexplained hypertension that does not respond to usual drugs. It is treated with a low sodium diet and a potassium-sparing diuretic such as amiloride, which blocks the channel directly, whereas spironolactone does not work. It is named for the American endocrinologist Grant Liddle, who described it in 1963.