Familial hyperaldosteronism type 2

Familial hyperaldosteronism type 2 is an autosomal dominant form of primary aldosteronism caused predominantly by gain-of-function mutations in the CLCN2 gene, which encodes the ClC-2 voltage-gated chloride channel. These mutations lead to increased channel opening, resulting in membrane depolarization of adrenal zona glomerulosa cells, activation of calcium signaling, and autonomous overproduction of aldosterone. Unlike type 1, this condition is non-suppressible with glucocorticoids and exhibits significant phenotypic overlap with sporadic primary aldosteronism, frequently presenting with early-onset hypertension, variable hypokalemia, and a high prevalence of aldosterone-producing adenomas. Diagnostic evaluation relies on demonstrating primary aldosteronism in multiple family members after excluding glucocorticoid-remediable aldosteronism, and clinical management centers on mineralocorticoid receptor antagonists or surgical adrenalectomy when unilateral adenomas are identified.