Integrating genetics and genomics in primary aldosteronism

Single-Nucleus Analysis Reveals Tumor Heterogeneity of Aldosterone-Producing Adenoma

BACKGROUND

Recent advances in omics techniques have allowed detailed genetic characterization of aldosterone-producing adenoma (APA). The pathogenesis of APA is characterized by tumorigenesis-associated aldosterone synthesis. The pathophysiological intricacies of APAs have not yet been elucidated at the level of individual cells. Therefore, a single-cell level analysis is speculated to be valuable in studying the differentiation process of APA.

METHODS

We conducted single-nucleus RNA sequencing of APAs with KCNJ5 mutation and nonfunctional adenomas obtained from 3 and 2 patients, respectively.

RESULTS

The single-nucleus RNA sequencing revealed the intratumoral heterogeneity of APA and identified cell populations consisting of a shared cluster of nonfunctional adenoma and APA. In addition, we extracted 2 cell fates in APA and obtained a cell population specialized in aldosterone synthesis. Genes related to ribosomes and neurodegenerative diseases were upregulated in 1 of these fates, whereas those related to the regulation of glycolysis were upregulated in the other fate. Furthermore, the total RNA reads in the nucleus were higher in hormonally activated clusters, indicating a marked activation of transcription per cell.

CONCLUSIONS

The single-nucleus RNA sequencing revealed intratumoral heterogeneity of APA with KCNJ5 mutation. The observation of 2 cell fates in KCNJ5-mutated APAs provides the postulation that a heterogeneous process of cellular differentiation was implicated in the pathophysiological mechanisms underlying APA tumors.

Molecular tools for diagnosing diseases of the adrenal cortex

PURPOSE OF REVIEW

The adrenal glands produce some of the most essential for life hormones, including cortisol and other steroids, and catecholamines. The former is produced from the adrenal cortex, whereas the latter is from the medulla. The two parts are anatomically and functionally distinct and it would be impossible in the context of one short article to cover all molecular updates on both the cortex and the medulla. Thus, in this review, we focus on the molecular tools available for diagnosing adrenocortical diseases, such as adrenal insufficiency, Cushing and Conn syndromes, and their potential for advancing medical care and clinical outcome.

RECENT FINDINGS

The advent of next generation sequencing opened doors for finding genetic diseases and signaling pathways involved in adrenocortical diseases. In addition, the combination of molecular data and clinicopathologic assessment might be the best approach for an early and precise diagnosis contributing to therapeutic decisions and improvement of patient outcomes.

SUMMARY

Diagnosing adrenocortical diseases can be challenging; however, the progress of molecular tools for adrenocortical disease diagnosis has greatly contributed to early detection and to meliorate patient outcomes.

Identification of a chromatin regulator signature and potential prognostic ability for adrenocortical carcinoma

Objective: Adrenocortical carcinoma (ACC) is a rare malignant tumor. Chromatin regulators (CRs) can drive epigenetic changes, which have been considered as one of the most vital hallmarks of tumors. This study aimed to explore the CR signature for ACC in order to clarify the molecular basis of ACC’s pathogenic mechanism and provide novel methods to diagnose and treat ACC clinically.

Methods: This study obtained transcriptome sequencing datasets of ACC patients and sequencing data on normal adrenal tissues in TCGA and GTEx databases, respectively. Meanwhile, prognostic genes were selected through Lasso and Cox regression analyses. Using the transcriptome sequencing datasets of ACC patients downloaded from the GEO database to finish validation, we performed Kaplan–Meier (KM) analysis for evaluating the differential survival between low- and high-risk groups. Then, this work constructed the risk model for predicting ACC prognosis. TIMER 2.0 was employed to assess the differences in immune infiltration between the two groups. Furthermore, this work adopted the R package “pRRophetic” for exploring and estimating the sensitivity of patients to different chemotherapeutic agents.

Results: A 5-CR model was established to predict ACC survival, and the CR signature was confirmed as a factor in order to independently predict ACC patient prognosis. In addition, a nomogram composed of the risk score and clinical T stage performed well in the prediction of patients’ prognosis. Differentially expressed CRs (DECRs) were mostly associated with the cell cycle, base excision repair, colon cancer, gene duplication, homologous recombination, and other signaling pathways for the high-risk group. As for the low-risk group, DECRs were mainly enriched in allograft rejection, drug metabolism of cytochrome P450, metabolism of xenogeneic organisms by cytochrome P450, retinol metabolism, and other signaling pathways. According to TIMER analysis, the immune infiltration degrees of endothelial cells, M2 macrophages, myeloid dendritic cells, CD4+ Th1 cells, NKT cells, and M0 macrophages showed significant statistical differences between the high- and low-risk groups, and high infiltration levels of M0 and M2 macrophages were more pronounced in higher T stage (T3 and T4), N stage (N1), and clinical stages (III and IV). In addition, high-risk cases exhibited higher sensitivity to etoposide and doxorubicin. Additionally, low-risk patients had significantly decreased expression of RRM1 compared with high-risk cases, suggesting the better effect of mitotane treatment.

Conclusion: This study identified the DECRs, which might be related to ACC genesis and progression. The pathways enriched by these DECRs were screened, and these DECRs were verified with excellent significance for estimating ACC survival. Drug sensitivity analysis also supported the current clinical treatment plan. Moreover, this study will provide reliable ideas and evidence for diagnosing and treating ACC in the clinic.

Molecular Mechanisms of Functional Adrenocortical Adenoma and Carcinoma: Genetic Characterization and Intracellular Signaling Pathway

The adrenal cortex produces steroid hormones as adrenocortical hormones in the body, secreting mineralocorticoids, glucocorticoids, and adrenal androgens, which are all considered essential for life. Adrenocortical tumors harbor divergent hormonal activity, frequently with steroid excess, and disrupt homeostasis of the body. Aldosterone-producing adenomas (APAs) cause primary aldosteronism (PA), and cortisol-producing adenomas (CPAs) are the primary cause of Cushing’s syndrome. In addition, adrenocortical carcinoma (ACC) is a highly malignant cancer harboring poor prognosis. Various genetic abnormalities have been reported, which are associated with possible pathogenesis by the alteration of intracellular signaling and activation of transcription factors. In particular, somatic mutations in APAs have been detected in genes encoding membrane proteins, especially ion channels, resulting in hypersecretion of aldosterone due to activation of intracellular calcium signaling. In addition, somatic mutations have been detected in those encoding cAMP-PKA signaling-related factors, resulting in hypersecretion of cortisol due to its driven status in CPAs. In ACC, mutations in tumor suppressor genes and Wnt-β-catenin signaling-related factors have been implicated in its pathogenesis. In this article, we review recent findings on the genetic characteristics and regulation of intracellular signaling and transcription factors in individual tumors.

MicroRNAs and Adrenocortical Tumors: Where do we Stand on Primary Aldosteronism?

MicroRNAs, the endogenous mediators of RNA interference, interact with the renin-angiotensin-aldosterone system, regulate aldosterone secretion and aldosterone effects. Some novel data show that the expression of some microRNAs is altered in primary aldosteronism, and some of these appear to have pathogenic relevance, as well. Differences in the circulating microRNA expression profiles between the two major forms of primary aldosteronism, unilateral aldosterone-producing adenoma and bilateral adrenal hyperplasia have also been shown. Here, we present a brief synopsis of these findings focusing on the potential relevance of microRNA in primary aldosteronism.

In situ metabolomics of aldosterone-producing adenomas

Recent genetic examinations and multisteroid profiles have provided the basis for subclassification of aldosterone-producing adenomas (APAs). The objective of the current study was to produce a comprehensive, high-resolution mass spectrometry imaging (MSI) map of APAs in relation to morphometry, immunohistochemical profiles, mutational status, and clinical outcome. The study cohort comprised 136 patients with unilateral primary aldosteronism. Matrix-assisted laser desorption/ionization-Fourier transform-ion cyclotron resonance MSI was conducted, and metabolite profiles were analyzed with genotype/phenotype information, including digital image analysis from morphometry and IHC of steroidogenic enzymes. Distinct molecular signatures between KCNJ5- and CACNA1D-mutated APAs with significant differences of 137 metabolites, including metabolites of purine metabolism and steroidogenesis, were observed. Intratumor concentration of 18-oxocortisol and 18-hydroxycortisol were inversely correlated with the staining intensity of CYP11B1. Lower staining intensity of CYP11B1 and higher levels of 18-oxocortisol were associated with a higher probability of complete clinical success after surgery. The present study demonstrates distinct metabolomic profiles of APAs in relation to tumor genotype. In addition, we reveal an inverse correlation between cortisol derivatives and CYP11B1 and the impact of 18-oxocortisol and CYP11B1 on clinical outcome, which provides unprecedented insights into the pathophysiology, clinical features, and steroidogenesis of APAs.

Matrix vesicles induce calcification of recipient vascular smooth muscle cells through multiple signaling pathways

In patients with chronic kidney and end-stage renal diseases, the major risk factor for progression of arterial calcification is the presence of existing (baseline) calcification. Here, we tested whether calcification of arteries is extended from calcified vascular smooth muscle cells (VSMCs) to adjacent normal cells by matrix vesicle-induced alteration of cell signaling. Matrix vesicles isolated from VSMC of rats with chronic kidney disease were co-cultured with VSMCs from normal littermates. Endocytosis of vesicles by recipient cells was confirmed by confocal microscopy. The addition of cellular matrix vesicles with characteristics of exosomes and low fetuin-A content enhanced the calcification of recipient VSMC. Further, only cellular-derived matrix vesicles induced an increase in intracellular calcium ion concentration, NOX1 (NADPH oxidase) and the anti-oxidant superoxide dismutase-2 in recipient normal VSMC. The increase in intracellular calcium ion concentration was due to release from endoplasmic reticulum and partially attributed to the activation of both NOX1 and mitogen-activated protein kinase (MEK1 and Erk1/2) signaling, since inhibiting both pathways blocked the increase in intracellular calcium ion in recipient VSMC. In contrast, matrix vesicles isolated from the media had no effect on the intracellular calcium ion concentration or MEK1 signaling, and did not induce calcification. However, media matrix vesicles did increase Erk1/2, although not to the level of cellular matrix vesicles, and NOX1 expression. Blockade of NOX activity further inhibited the cellular matrix vesicle-induced accelerated calcification of recipient VSMC, suggesting a potential therapeutic role of such inhibition. Thus, addition of cellular-derived matrix vesicles from calcifying VSMC can accelerate calcification by inducing cell signaling changes and phenotypic alteration of recipient VSMC.

Molecular characteristics of the KCNJ5 mutated aldosterone-producing adenomas

The pathophysiology of aldosterone-producing adenomas (APAs) has been investigated via genetic approaches and the pathogenic significance of a series of somatic mutations, including KCNJ5, has been uncovered. However, how the mutational status of an APA is associated with its molecular characteristics, including its transcriptome and methylome, has not been fully understood. This study was undertaken to explore the molecular characteristics of APAs, specifically focusing on APAs with KCNJ5 mutations as opposed to those without KCNJ5 mutations, by comparing their transcriptome and methylome status. Cortisol-producing adenomas (CPAs) were used as reference. We conducted transcriptome and methylome analyses of 29 APAs with KCNJ5 mutations, 8 APAs without KCNJ5 mutations and 5 CPAs. Genome-wide gene expression and CpG methylation profiles were obtained from RNA and DNA samples extracted from these 42 adrenal tumors. Cluster analysis of the transcriptome and methylome revealed molecular heterogeneity in APAs depending on their mutational status. DNA hypomethylation and gene expression changes in Wnt signaling and inflammatory response pathways were characteristic of APAs with KCNJ5 mutations. Comparisons between transcriptome data from our APAs and that from normal adrenal cortex obtained from the Gene Expression Omnibus suggested similarities between APAs with KCNJ5 mutations and zona glomerulosa. The present study, which is based on transcriptome and methylome analyses, indicates the molecular heterogeneity of APAs depends on their mutational status. Here, we report the unique characteristics of APAs with KCNJ5 mutations.

Expression of CYP11B2 in Aldosterone-Producing Adrenocortical Adenoma: Regulatory Mechanisms and Clinical Significance

Aldosterone-producing adrenocortical adenoma (APA) is responsible for the majority of cases clinically diagnosed as primary aldosteronism. Aldosterone synthase (CYP11B2) is one of the enzymes that play essential roles in aldosterone synthesis and is involved in the pathogenesis of APA. Recent studies have demonstrated that various factors and regulators influence the expression and function of CYP11B2 in APA. In particular, somatic mutations, such as gain-of-function and loss-of-function mutations, have been identified in several genes, each of which encodes a pivotal protein that affects the calcium signaling pathway, the expression of CYP11B2, and aldosterone production. The gain-of-function mutations were reported in KCNJ5 that encodes G-protein activated inward rectifier K⁺ channel 4 (Kir3.4) and in CACNA1D, encoding calcium channel, voltage-dependent, L type, alpha subunit Cav1.3. The loss-of-function mutations were found in ATP1A1 that encodes Na⁺/K⁺ ATPase α subunit and in ATP2B3, encoding Ca²⁺ ATPase. Furthermore, the aberrant expression of gonadotropin-releasing hormone receptor is associated with the overexpression of CYP11B2 and overproduction of aldosterone in APA with activating mutations in CTNNB1 encoding β-catenin. On the other hand, CYP11B2 also catalyzes the conversion of cortisol to 18-hydroxycortisol and subsequently converts 18-hydroxycortisol to 18-oxocortisol. The recent studies have identified 18-oxocortisol as an important and distinct biomarker to diagnose primary aldosteronism. In this review, we summarize the recent findings on CYP11B2 and discuss the molecular pathogenesis of APA and the clinical significance of CYP11B2.

Expression of inflammation-related genes in aldosterone-producing adenomas with KCNJ5 mutation

BACKGROUND

The adrenocortical cells have been shown to produce various inflammatory cytokines such as TNFα and IL-6, which could modulate steroidogenesis. However, the role of inflammatory cytokines in aldosterone-producing adenomas (APAs) is not fully understood. In the present study, we examined the relationships between mRNA expression levels of the inflammation-related genes and somatic mutations in APA tissues.

METHODS

We evaluated mRNA expression levels of TNFA, IL6, and NFKB1 in APA tissues obtained from 44 Japanese APA patients.

RESULTS

We revealed that mRNA expression patterns of the inflammation-related genes depended on a KCNJ5 somatic mutation. In addition, we showed that mRNA expression levels of the inflammation-related genes correlated with those of the steroidogenic enzyme CYP11B1 in the patients with APAs.

CONCLUSION

The present study documented for the first time the expression of inflammation-related genes in APAs and the correlation of their expression levels with the KCNJ5 mutation status and mRNA expression levels of steroidogenic enzymes, indicating the pathophysiological relevance of inflammation-related genes in APAs.

A Novel Somatic Deletion Mutation of ATP2B3 in Aldosterone-Producing Adenoma

Aldosterone-producing adenoma (APA) is a form of primary aldosteronism (PA). Recent studies suggested that somatic mutations in the KCNJ5, ATP1A1, ATP2B3, and CACNA1D genes are involved in the pathogenesis of APA. We report a case of a 62-year-old man diagnosed as PA with left adrenal mass. He underwent adrenalectomy for treatment. We identified a novel somatic deletion mutation in ATP2B3 in the adrenal tumor: c.1269_1274delTGTGCT which spans three codons (423-425) resulting in p.Val424_Leu425del. Immunohistochemical analysis revealed strong expression of aldosterone synthase (CYP11B2) in the tumor tissue, which is consistent with APA. Here, we identified a novel somatic deletion mutation in ATP2B3, which results in the amino acid sequences increasing intracellular calcium concentrations as reported previously, leading to increased aldosterone synthase (CYP11B2) expression and following excess aldosterone production in the APA cells. The novel ATP2B3 mutation detected in our case supports the pathogenic significance of the locus spanning the codon 424-426 of ATP2B3.

Integration of transcriptome and methylome analysis of aldosterone-producing adenomas

OBJECTIVE

The pathophysiology of aldosterone-producing adenomas (APA) has been investigated intensively through genetic and genomic approaches. However, the role of epigenetics in APA is not fully understood. In the present study, we explored the relationship between gene expression and DNA methylation status in APA.

METHODS

We conducted an integrated analysis of transcriptome and methylome data of paired APA-adjacent adrenal gland (AAG) samples from the same patient. The adrenal specimens were obtained from seven Japanese patients with APA who underwent adrenalectomy. Gene expression and genome-wide CpG methylation profiles were obtained from RNA and DNA samples that were extracted from those seven paired tissues.

RESULTS

Methylome analysis showed global CpG hypomethylation in APA relative to AAG. The integration of gene expression and methylation status showed that 34 genes were up-regulated with CpG hypomethylation in APA. Of these, three genes (CYP11B2, MC2R, and HPX) may be related to aldosterone production, and five genes (PRRX1, RAB38, FAP, GCNT2, and ASB4) are potentially involved in tumorigenesis.

CONCLUSION

The present study is the first methylome analysis to compare APA with AAG in the same patients. Our integrated analysis of transcriptome and methylome revealed DNA hypomethylation in APA and identified several up-regulated genes with DNA hypomethylation that may be involved in aldosterone production and tumorigenesis.

Understanding primary aldosteronism: impact of next generation sequencing and expression profiling

Primary aldosteronism (PA) encompasses a broad, heterogeneous group of disorders including both sporadic and familial forms (familial hyperaldosteronism type I, II and III). PA is the most common form of secondary hypertension and associated with a higher rate of cardiovascular complications, compared with essential hypertension. Despite significant progress in the diagnosis and management of PA, until recently the molecular mechanisms leading to inappropriate aldosterone production were largely unknown. The introduction of next-generation sequencing has had a profound impact on the field of human genetics and has given new insight in the molecular determinants that lead to both sporadic and familial forms of PA. Here we review the recent progress toward understanding of the genetic and molecular mechanisms leading to autonomous aldosterone production in PA.

Overview of the genetic determinants of primary aldosteronism

Primary aldosteronism is the most common cause of secondary hypertension. The syndrome accounts for 10% of all cases of hypertension and is primarily caused by bilateral adrenal hyperplasia or aldosterone-producing adenoma. Over the last few years, the use of exome sequencing has significantly improved our understanding of this syndrome. Somatic mutations in the KCNJ5, ATP1A1, ATP2B3 or CACNA1D genes are present in more than half of all cases of aldosterone-producing adenoma (~40%, ~6%, ~1% and ~8%, respectively). Germline gain-of-function mutations in KCNJ5 are now known to cause familial hyperaldosteronism type III, and an additional form of genetic hyperaldosteronism has been reported in patients with germline mutations in CACNA1D. These genes code for channels that control ion homeostasis across the plasma membrane of zona glomerulosa cells. Moreover, all these mutations modulate the same pathway, in which elevated intracellular calcium levels lead to aldosterone hyperproduction and (in some cases) adrenal cell proliferation. From a clinical standpoint, the discovery of these mutations has potential implications for patient management. The mutated channels could be targeted by drugs, in order to control hormonal and overgrowth-related manifestations. Furthermore, some of these mutations are associated with high cell turnover and may be amenable to diagnosis via the sequencing of cell-free (circulating) DNA. However, genotype-phenotype correlations in patients harboring these mutations have yet to be characterized. Despite this recent progress, much remains to be done to elucidate the yet unknown mechanisms underlying sporadic bilateral adrenal hyperplasia.

Integrated analysis of genome-wide methylation and gene expression shows epigenetic regulation of CYP11B2 in aldosteronomas

CONTEXT

Differential methylation of CpG regions is the best-defined mechanism of epigenetic regulation of gene expression.

OBJECTIVE

Our objective was to determine whether any changes in methylation are associated with aldosteronomas.

METHODS

We performed integrated genome-wide methylation and gene expression profiling in aldosteronomas (n = 25) as compared with normal adrenal cortical tissue (n = 10) and nonfunctioning adrenocortical tumors (n = 13). To determine the effect of demethylation on gene expression of CYP11B2, the H295R cell line was used.

RESULTS

The methylome of aldosteronomas, normal adrenal cortex, and nonfunctioning adrenocortical tumors was distinct, with hypomethylation of aldosteronomas. Integrated analysis of gene expression and methylation status showed that 53 of 60 genes were hypermethylated and downregulated, or hypomethylated and upregulated, in aldosteronomas. Of these, 3 genes that regulate steroidogenic signals and synthesis in adrenocortical cells were differentially methylated: AVPR1α and PRKCA were downregulated and hypermethylated, and CYP11B2 was upregulated and hypomethylated. Demethylation treatment resulted in upregulation of these genes, with direct hypomethylation of CpG sites associated with the genes. The CpG island in the promoter region of CYP11B2 was hypomethylated in aldosteronomas but not in blood DNA from the same patients (P = .0004).

CONCLUSIONS

Altered methylation in aldosteronomas is associated with dysregulated expression of genes involved in steroid biosynthesis. Aldosteronomas are hypomethylated, and CYP11B2 is overexpressed and hypomethylated in these tumors.

Colon-specific deletion of epithelial sodium channel causes sodium loss and aldosterone resistance

Aldosterone promotes electrogenic sodium reabsorption through the amiloride-sensitive epithelial sodium channel (ENaC). Here, we investigated the importance of ENaC and its positive regulator channel-activating protease 1 (CAP1/Prss8) in colon. Mice lacking the αENaC subunit in colonic superficial cells (Scnn1a(KO)) were viable, without fetal or perinatal lethality. Control mice fed a regular or low-salt diet had a significantly higher amiloride-sensitive rectal potential difference (∆PDamil) than control mice fed a high-salt diet. In Scnn1a(KO) mice, however, this salt restriction-induced increase in ∆PDamil did not occur, and the circadian rhythm of ∆PDamil was blunted. Plasma and urinary sodium and potassium did not change with regular or high-salt diets or potassium loading in control or Scnn1a(KO) mice. However, Scnn1a(KO) mice fed a low-salt diet lost significant amounts of sodium in their feces and exhibited high plasma aldosterone and increased urinary sodium retention. Mice lacking the CAP1/Prss8 in colonic superficial cells (Prss8(KO)) were viable, without fetal or perinatal lethality. Compared with controls, Prss8(KO) mice fed regular or low-salt diets exhibited significantly reduced ∆PDamil in the afternoon, but the circadian rhythm was maintained. Prss8(KO) mice fed a low-salt diet also exhibited sodium loss through feces and higher plasma aldosterone levels. Thus, we identified CAP1/Prss8 as an in vivo regulator of ENaC in colon. We conclude that, under salt restriction, activation of the renin-angiotensin-aldosterone system in the kidney compensated for the absence of ENaC in colonic surface epithelium, leading to colon-specific pseudohypoaldosteronism type 1 with mineralocorticoid resistance without evidence of impaired potassium balance.

Role of KCNJ5 in familial and sporadic primary aldosteronism

Primary aldosteronism is characterised by the dysregulation of aldosterone production and comprises both sporadic forms, caused by an aldosterone-producing adenoma or bilateral adrenal hyperplasia, and familial forms (familial hyperaldosteronism types I, II and III). The two principal physiological regulators of aldosterone synthesis are angiotensin II and serum K(+), which reverse the high resting K(+) conductance and hyperpolarized membrane potential of adrenal glomerulosa cells. The resulting membrane depolarization causes the opening of voltage-gated Ca(2+) channels and an increase in intracellular Ca(2+) that stimulates aldosterone biosynthesis. Point mutations in the KCNJ5 gene, which encodes the G-protein-activated inward rectifier K(+) channel 4 (GIRK4), have been implicated in the pathogenesis of both sporadic and familial forms of primary aldosteronism. These mutations interfere with the selectivity filter of GIRK4 causing Na(+) entry, cell depolarization and Ca(2+) channel opening, resulting in constitutive aldosterone production. Seven families with familial hyperaldosteronism caused by KCNJ5 germline mutations have so far been described, and multicentre studies have reported KCNJ5 mutations in approximately 40% of sporadic aldosterone-producing adenomas. Herein, we review the role of GIRK4 in adrenal pathophysiology and provide an overview of the clinical and biochemical phenotypes resulting from KCNJ5 mutations in patients with sporadic and familial primary aldosteronism.

Association of CYP11B2 polymorphisms with susceptibility to primary aldosteronism: a meta-analysis

The association of CYP11B2 gene polymorphisms with the risk of primary aldosteronism (PA) was controversial in previous studies. Here we selected two commonly studied CYP11B2 alleles: T-344C, A2718G to explore their associations with PA risk by meta-analyses of published case-control studies. Six electronic databases were searched for relevant studies up to November 2012. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using random or fixed effects model. Seven studies (621 cases and 1027 controls) on T-344C polymorphism, three studies (327 cases and 336 controls) on A2718G polymorphism were finally included. Then significant association was observed between T-344C polymorphism and idiopathic hyperaldosteronism (IHA) under three genetic models (CC vs. TT, OR=0.544, 95% CI=0.324~0.914; CT vs. TT, OR=0.554, 95% CI=0.406~0.757; CC+CT vs. TT, OR=0.542, 95% CI=0.402~0.731). But patients with aldosterone-producing adenoma had no significant association with T-344C polymorphism under all genetic models except CT vs. TT model. Concerning A2718G polymorphism, a decreased PA risk was observed only under GG+GA vs AA model. But this association disappeared after removing the studies not in Hardy-Weinberg equilibrium. The evidence accumulated suggested that -344C allele may be associated with decreased risk of IHA and there was still no enough evidence to indicate the association of A2718G polymorphism with PA risk.