At least 5% of individuals with hypertension have adrenal aldosterone-producing adenomas (APAs). Gain-of-function mutations in KCNJ5 and apparent loss-of-function mutations in ATP1A1 and ATP2A3 were reported to occur in APAs. We find that KCNJ5 mutations are common in APAs resembling cortisol-secreting cells of the adrenal zona fasciculata but are absent in a subset of APAs resembling the aldosterone-secreting cells of the adrenal zona glomerulosa. We performed exome sequencing of ten zona glomerulosa-like APAs and identified nine with somatic mutations in either ATP1A1, encoding the Na(+)/K(+) ATPase α1 subunit, or CACNA1D, encoding Cav1.3. The ATP1A1 mutations all caused inward leak currents under physiological conditions, and the CACNA1D mutations induced a shift of voltage-dependent gating to more negative voltages, suppressed inactivation or increased currents. Many APAs with these mutations were <1 cm in diameter and had been overlooked on conventional adrenal imaging. Recognition of the distinct genotype and phenotype for this subset of APAs could facilitate diagnosis.

SUMMARYRecent discoveries of somatic mutations permit the recognition of subtypes of aldosteroneproducing adenomas with distinct clinical presentations and pathological features. Here we describe three women with hyperaldosteronism, two who presented in pregnancy and one who presented after menopause. Their aldosterone-producing adenomas harbored activating mutations of CTNNB1, encoding β-catenin in the Wnt cell-differentiation pathway, and expressed LHCGR and GNRHR, encoding gonadal receptors, at levels that were more than 100 times as high as the levels in other aldosterone-producing adenomas. The mutations stimulate Wnt activation and cause adrenocortical cells to de-differentiate toward their common adrenal-gonadal precursor cell type.Systematic screening detects primary aldosteronism in 5 to 10% of all patients with hypertension and in approximately 20% of patients with treatment-resistant hypertension. 1,2 A unilateral aldosterone-producing adenoma is the most common potentially curable cause of hypertension in such cases. 2 Early detection of a unilateral aldosterone-producing adenoma is important both to maximize the likelihood of a complete cure of hypertension by means of adenoma removal and to prevent the onset of resistant hypertension and the risk of long-term cardiovascular complications. 3 The Wnt pathway, through β-catenin signaling, is critical for normal adrenocortical development and maintenance, in particular the zona glomerulosa of the cortex. 4 Both the adrenal cortex and the gonads originate from a common progenitor-cell population in the Pathogenic somatic mutations of CTNNB1 have been found in 27% of adrenocortical adenomas and in 31% of adrenocortical carcinomas. 7 Some of these mutations arise in the part of exon 3 that encodes the consensus glycogen synthase kinase 3β-casein kinase 1 (GSK-3β-CK1) phosphorylation site and therefore result in loss of phosphorylation of β-catenin. This prevents the ubiquitination of β-catenin and leads to aberrant Wnt-pathway activation. 8 Until now, β-catenin mutations in adrenocortical adenomas have been mainly associated with nonfunctioning tumors. 7 Could some of these tumors be nonfunctioning only because they have not been exposed to the stimulus for hormone secretion?Here we describe three patients with hyperaldosteronism, two presenting during pregnancy and one after menopause, who were discovered to have mutations in exon 3 of CTNNB1 in their adenomas. All three mutations were predicted to stabilize nonphosphorylated β-catenin and to activate the Wnt signaling pathway. All three aldosterone-producing adenomas expressed very high levels of the gonadal receptors luteinizing hormone-chorionic gonadotropin receptor (LH-CGR) and gonadotropin-releasing hormone receptor (GNRHR). It therefore seems likely that high circulating levels of human chorionic gonadotropin, luteinizing hormone, or gonadotropin-releasing hormone (as observed in pregnancy or at menopause) led to the identification of the aldosterone-producing adenomas in the three patients. CASE ...

Context:Aldosterone synthesis and cellularity in the human adrenal zona glomerulosa (ZG) is sparse and patchy, presumably due to salt excess. The frequency of somatic mutations causing aldosterone-producing adenomas (APAs) may be a consequence of protection from cell loss by constitutive aldosterone production.Objective:The objective of the study was to delineate a process in human ZG, which may regulate both aldosterone production and cell turnover.Design:This study included a comparison of 20 pairs of ZG and zona fasciculata transcriptomes from adrenals adjacent to an APA (n = 13) or a pheochromocytoma (n = 7).Interventions:Interventions included an overexpression of the top ZG gene (LGR5) or stimulation by its ligand (R-spondin-3).Main Outcome Measures:A transcriptome profile of ZG and zona fasciculata and aldosterone production, cell kinetic measurements, and Wnt signaling activity of LGR5 transfected or R-spondin-3-stimulated cells were measured.Results:LGR5 was the top gene up-regulated in ZG (25-fold). The gene for its cognate ligand R-spondin-3, RSPO3, was 5-fold up-regulated. In total, 18 genes associated with the Wnt pathway were greater than 2-fold up-regulated. ZG selectivity of LGR5, and its absence in most APAs, were confirmed by quantitative PCR and immunohistochemistry. Both R-spondin-3 stimulation and LGR5 transfection of human adrenal cells suppressed aldosterone production. There was reduced proliferation and increased apoptosis of transfected cells, and the noncanonical activator protein-1/Jun pathway was stimulated more than the canonical Wnt pathway (3-fold vs 1.3-fold). ZG of adrenal sections stained positive for apoptosis markers.Conclusion:LGR5 is the most selectively expressed gene in human ZG and reduces aldosterone production and cell number. Such conditions may favor cells whose somatic mutation reverses aldosterone inhibition and cell loss.