Liddle syndrome

Liddle syndrome is an inherited form of hypertension caused by overactive epithelial sodium channels in the kidney, which retain sodium and promote potassium loss.

Epithelial sodium channel: A sodium-selective channel in epithelial cells that enables sodium uptake, including in the kidney’s collecting duct. Its excessive activity is the direct cause of sodium retention in Liddle syndrome.
Autosomal dominant inheritance: An inheritance pattern in which one altered gene copy can cause a trait or disorder. Liddle syndrome commonly appears across generations through this pattern.
Primary aldosteronism: Hypertension caused by excess aldosterone production, often with suppressed renin and low potassium. It resembles Liddle syndrome clinically, but aldosterone is elevated rather than suppressed.
Genetic testing: Laboratory analysis of DNA to identify disease-associated genetic variants. Testing SCNN1B, SCNN1G, or SCNN1A can confirm an inherited channel disorder.
SCNN1B: A gene encoding the beta subunit of the epithelial sodium channel. Many Liddle syndrome variants in this gene disrupt channel removal from the cell surface.
Collecting duct: The final nephron segment that adjusts urine composition and water balance. Its sodium-reabsorbing cells are where epithelial sodium channel activity drives the syndrome.
Apparent mineralocorticoid excess: A disorder in which impaired cortisol inactivation allows cortisol to activate mineralocorticoid receptors. It can cause low-renin, low-aldosterone hypertension through receptor activation rather than channel mutations.
Hyporeninemic hypoaldosteronism: A biochemical state with low renin and low aldosterone concentrations. This hormonal pattern supports Liddle syndrome when paired with hypertension and potassium loss.
SCNN1G: A gene encoding the gamma subunit of the epithelial sodium channel. Variants in this channel-subunit gene can also cause Liddle syndrome.
Nephron: The kidney’s microscopic functional unit, which filters blood and modifies the resulting fluid into urine. The collecting duct is one segment of this larger kidney structure.

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