Somatic and germline CACNA1D calcium channel mutations in aldosterone-producing adenomas and primary aldosteronism

Richard Lifton and colleagues identify somatic and germline mutations in the CACNA1D calcium channel gene in aldosterone-producing adenomas and primary aldosteronism. Their functional studies show that these mutations result in channel activation at more hyperpolarized membrane potentials, implicating increased Ca 2+ influx in disease pathogenesis. Adrenal aldosterone-producing adenomas (APAs) constitutively produce the salt-retaining hormone aldosterone and are a common cause of severe hypertension. Recurrent mutations in the potassium channel gene KCNJ5 that result in cell depolarization and Ca 2+ influx cause ∼40% of these tumors 1 . We identified 5 somatic mutations (4 altering Gly403 and 1 altering Ile770) in CACNA1D , encoding a voltage-gated calcium channel, among 43 APAs without mutated KCNJ5 . The altered residues lie in the S6 segments that line the channel pore. Both alterations result in channel activation at less depolarized potentials; Gly403 alterations also impair channel inactivation. These effects are inferred to cause increased Ca 2+ influx, which is a sufficient stimulus for aldosterone production and cell proliferation in adrenal glomerulosa 2 . We also identified de novo germline mutations at identical positions in two children with a previously undescribed syndrome featuring primary aldosteronism and neuromuscular abnormalities. These findings implicate gain-of-function Ca 2+ channel mutations in APAs and primary aldosteronism.