K + Channel Mutations in Adrenal Aldosterone-Producing Adenomas and Hereditary Hypertension

Abstract

Endocrine tumors such as aldosterone-producing adrenal adenomas (APAs), a cause of severe hypertension, feature constitutive hormone production and unrestrained cell proliferation; the mechanisms linking these events are unknown. We identify two recurrent somatic mutations in and near the selectivity filter of the potassium (K⁺) channel KCNJ5 that are present in 8 of 22 human APAs studied. Both produce increased sodium (Na⁺) conductance and cell depolarization, which in adrenal glomerulosa cells produces calcium (Ca²⁺) entry, the signal for aldosterone production and cell proliferation. Similarly, we identify an inherited KCNJ5 mutation that produces increased Na⁺ conductance in a Mendelian form of severe aldosteronism and massive bilateral adrenal hyperplasia. These findings explain pathogenesis in a subset of patients with severe hypertension and implicate loss of K⁺ channel selectivity in constitutive cell proliferation and hormone production.