Liddle Syndrome

Liddle Syndrome is a rare genetic condition that affects the kidneys and how they handle salt and water. It causes the body to retain too much sodium, which leads to high blood pressure and low levels of potassium in the blood. This condition involves a problem with a specific part of the kidney called the epithelial sodium channel (ENaC), which becomes overactive. Because of this, the kidneys hold on to extra salt and water, increasing blood volume and pressure. People with this syndrome often develop hypertension at a young age and may have symptoms related to low potassium, such as muscle weakness or cramps. It is important to recognize this condition because it can be treated differently from other causes of high blood pressure.

Liddle Syndrome is an autosomal dominant disorder caused by mutations in the SCNN1A, SCNN1B, or SCNN1G genes encoding the subunits of the epithelial sodium channel (ENaC) in the distal nephron. These mutations lead to constitutive activation of ENaC, resulting in increased sodium reabsorption independent of aldosterone regulation. The pathophysiology involves enhanced sodium retention, volume expansion, hypertension, hypokalemia, and metabolic alkalosis. Unlike other forms of hypertension, plasma renin activity and aldosterone levels are suppressed due to negative feedback from volume overload. Clinically, patients present with early-onset hypertension and hypokalemia without edema. The syndrome is significant because it mimics hyperaldosteronism but requires different management targeting ENaC rather than aldosterone.