Genetic mechanisms of primary aldosteronism.

Genetic mechanisms of primary aldosteronism.

Hypertension Editors' Picks: Hyperaldosteronism.

Disclosure: K. Aiga: None. M. Kometani: None. D. Aono: None. S. Karashima: None. T. Yoneda: None. Primary aldosteronism (PA) is a major cause of secondary hypertension. PA is known to have higher prevalence of cerebral or cardiovascular complications, indicating the importance of early detection and treatment for PA. PA is caused by autonomous secretion of aldosterone in the adrenal glands. PA is characterized by high plasma aldosterone concentration, low plasma renin activity and hypokalemia. PA is classified into unilateral PA (aldosterone-producing adenoma [APA] or unilateral hyperplasia) and bilateral PA (bilateral adrenal hyperplasia). PA with aldosterone excess in bilateral adrenal glands is defined as bilateral PA. On the other hand, PA with aldosterone excess in unilateral adrenal gland is defined as unilateral PA. Strategies for PA treatment depends on the subtype of PA. Medication by mineralocorticoid receptor antagonists is a common treatment for bilateral PA. Adrenalectomy is the most efficient treatment for unilateral PA. In general, patients tend to maintain normal serum potassium level and blood pressure after adrenalectomy, and recurrence of PA is extremely rare. Recently, mutation in the gene named KCNJ5 was found to derive APA. Herein, we report two cases of PA recurrence more than 10 years after surgical treatment for APA. Somatic mutation in KCNJ5 was detected in the first occurrence of PA in both cases. First case, a 52-year-old woman was examined for hypertension 22 years after total adrenalectomy of the right adrenal gland. Recurrent PA was diagnosed based on high aldosterone-renin-ratio (ARR), identification of left adrenal gland tumor by computed tomography (CT), and a confirmatory test. Second case, a 65-year-old man was examined for hypertension 17 years after total adrenalectomy of the left adrenal gland. He had maintained his blood pressure using medication since the onset of hypertension 4 years after the surgery. A year later, a high ARR was observed. PA recurrence was determined by a right adrenal gland tumor noted on CT and a confirmatory test. Tissues of the adrenal gland were obtained from adrenalectomy in both cases. Histopathological analysis revealed presence of one adenoma in the first case, while two adenomas were confirmed in the second case. Somatic mutation in KCNJ5 gene was detected in both cases. To date, there are no specific guidelines established for the management of recurrent PA. Early detection is crucial for the prevention of severe cardiovascular diseases. Long-term follow-up is recommended after the treatment of PA. Presentation: Friday, June 16, 2023

Primary aldosteronism (PA) is the most frequent cause of secondary hypertension. Adrenal vein sampling (AVS) is an established method for finding patients with the unilateral subtype of PA, for which adrenalectomy is an applicable treatment. In this study, we analyzed a large database of patients with PA who underwent adrenal vein sampling, to investigate the sex differences in the impact of age at diagnosis on the subtype and cause of PA. In 2122 patients, women with the unilateral subtype were younger than men with the same subtype and women with the bilateral subtype. Younger age and older age were associated with unilateral PA in women and men, respectively. After stratification by tertiles of age, there was a trend of decreased and increased incidence of unilateral PA with aging in women and men, respectively. Male sex was a predictor of unilateral PA in middle-aged and older patients but not in younger patients. We also found that obesity, a known factor associated with idiopathic hyperaldosteronism, was positively associated with bilateral PA in younger patients but not in older patients. These findings suggest that the proportion of operable patients with unilateral PA differs depending on the combination of sex and age, and that other than obesity, the cause of PA is also associated with the bilateral subtype in older patients.

Adrenal venous sampling is recommended as the golden standard for subtyping primary aldosteronism (PA). However, it is invasive and inconvenient, and seeking a better way to make differential diagnosis of PA is necessary. The objective of the study was to evaluate the diagnostic value of ACTH stimulation test under 1 mg dexamethasone suppression test (DST) in determining the subtypes of PA. Ninety-five patients with PA confirmed by saline infusion test were included in this study. According to adrenal venous sampling and histopathology, 39 patients were diagnosed as bilateral adrenal hyperplasia (BAH), 37 as aldosterone-producing adenoma (APA), and 19 as unilateral adrenal hyperplasia (UAH). An ACTH stimulation test under 1 mg DST was performed in all patients. Plasma aldosterone and cortisol levels were measured every 30 minutes until 120 minutes after the iv injection of 50 IU ACTH. During the ACTH stimulation test, aldosterone levels in APA and UAH were similar (P > .05) but higher than those in BAH (P < .001). Furthermore, stimulated aldosterone levels of unilateral PA (APA and UAH) were significantly higher than bilateral PA (BAH) (P < .001). Receiver-operated characteristics curve analyses showed the aldosterone after ACTH stimulation was effective for distinguishing between unilateral PA and bilateral PA. The diagnostic accuracy was highest at 120 minutes after ACTH stimulation, and the optimal cutoff value of the aldosterone was 77.90 ng/dL, with a sensitivity of 76.8%, a specificity of 87.2%, a positive predictive value of 89.6%, and a negative predictive value of 72.3%. The ACTH stimulation test under 1 mg DST is useful to determine the subtypes of PA, especially in unilateral and bilateral PA, and may guide further treatment in PA patients.

Disclosure: L.S. Santana: None. A.G. Guimaraes: None. F. Freitas-Castro: None. A.W. Maciel: None. G.F. Fagundes: None. M.A. Pereira: None. L.F. Drager: None. L.A. Bortolotto: None. M.C. Fragoso: None. B.B. Mendonca: None. A. Latronico: None. M.Q. Almeida: None. Primary aldosteronism (PA) is the most common cause of endocrine hypertension, with an estimated prevalence of 10-20% in patients referred to tertiary hospitals. The most common causes of PA are bilateral adrenal hyperplasia (BAH) and aldosteronomas. Significant advances in elucidating the pathogenesis of PA have been made over the past decade. Pathogenic/likely pathogenic germline allelic variants in KCNJ5, CACNA1D, CACNA1H, CLCN2, PDE2A, and PDE3B genes have already been documented in individuals diagnosed with PA. However, most of the cases still lack a defined genetic etiology. Genomic investigation of these individuals through whole-exome sequencing (WES) would enable the identification of causal monogenic genotype-phenotype associations in genes not yet linked to bilateral PA. In our study, thirty-one patients were selected, including 29 probands and 2 relatives, with a confirmed diagnosis of bilateral PA by adrenal venous sampling. All probands were previously investigated for KCNJ5 pathogenic/likely pathogenic germline variants. Additionally, all cases also had negative genetic screening for glucocorticoid-remediable PA. WES was performed using BGI Genomics technology, DNA nanoball sequencing, on the DNBSEQ platform. Raw data were processed (bioinformatics) using in-house pipelines. The 31 sequenced samples showed excellent coverage metrics, with coverage ranging from 200-467X and %&amp;gt;10X at 99%. Each patient presented an average of 150,000 variants. After the gene/allelic prioritization workflow, 4 heterozygous SNVs were listed as candidates in 3 out of 29 patients (10.34%). Two of the variants were identified in rare but previously documented germline causes of PA: CACNA1H and CACNA1D (patients 13 and 29, respectively). Patient 4 (hypertension diagnosed at 36 years of age) presented 2 variants in possible new candidate genes, CASZ1 and STRN. The NM_001079843.3(CASZ1):c.1912G&amp;gt;C/p.(Asp638His) variant caught our attention not only for its absence in population genomic databases (gnomAD v.4), but also due to the association between CASZ1 locus and PA. The zinc finger transcription factor CASZ1 has CACNA1D as one of its targets and participates in key biological processes for PA pathogenesis, such as: co-repression of mineralocorticoid receptor transcriptional activity; mediation of tissue response to aldosterone and differential expression in aldosterone-producing cell clusters (APCC) and in zona glomerulosa; its hypoexpression promotes aldosterone-dependent mineralocorticoid receptor transcriptional activity and hyperexpression suppresses aldosterone biosynthesis by adrenal cells. In conclusion, an extremely rare CASZ1 variant was identified in a woman with bilateral PA. The functional characterization of the CASZ1 p.(Asp638His) variant might reinforce its role as a new monogenic cause of PA. Presentation: 6/3/2024

Disclosure: L.S. Santana: None. A.G. Guimaraes: None. F. Freitas-Castro: None. A.W. Maciel: None. G.F. Fagundes: None. M.A. Pereira: None. L.F. Drager: None. L.A. Bortolotto: None. M.C. Fragoso: None. B.B. Mendonca: None. A. Latronico: None. M.Q. Almeida: None. Primary aldosteronism (PA) is the most common cause of endocrine hypertension, with an estimated prevalence of 10-20% in patients referred to tertiary hospitals. The most common causes of PA are bilateral adrenal hyperplasia (BAH) and aldosteronomas. Significant advances in elucidating the pathogenesis of PA have been made over the past decade. Pathogenic/likely pathogenic germline allelic variants in KCNJ5, CACNA1D, CACNA1H, CLCN2, PDE2A, and PDE3B genes have already been documented in individuals diagnosed with PA. However, most of the cases still lack a defined genetic etiology. Genomic investigation of these individuals through whole-exome sequencing (WES) would enable the identification of causal monogenic genotype-phenotype associations in genes not yet linked to bilateral PA. In our study, thirty-one patients were selected, including 29 probands and 2 relatives, with a confirmed diagnosis of bilateral PA by adrenal venous sampling. All probands were previously investigated for KCNJ5 pathogenic/likely pathogenic germline variants. Additionally, all cases also had negative genetic screening for glucocorticoid-remediable PA. WES was performed using BGI Genomics technology, DNA nanoball sequencing, on the DNBSEQ platform. Raw data were processed (bioinformatics) using in-house pipelines. The 31 sequenced samples showed excellent coverage metrics, with coverage ranging from 200-467X and %&amp;gt;10X at 99%. Each patient presented an average of 150,000 variants. After the gene/allelic prioritization workflow, 4 heterozygous SNVs were listed as candidates in 3 out of 29 patients (10.34%). Two of the variants were identified in rare but previously documented germline causes of PA: CACNA1H and CACNA1D (patients 13 and 29, respectively). Patient 4 (hypertension diagnosed at 36 years of age) presented 2 variants in possible new candidate genes, CASZ1 and STRN. The NM_001079843.3(CASZ1):c.1912G&amp;gt;C/p.(Asp638His) variant caught our attention not only for its absence in population genomic databases (gnomAD v.4), but also due to the association between CASZ1 locus and PA. The zinc finger transcription factor CASZ1 has CACNA1D as one of its targets and participates in key biological processes for PA pathogenesis, such as: co-repression of mineralocorticoid receptor transcriptional activity; mediation of tissue response to aldosterone and differential expression in aldosterone-producing cell clusters (APCC) and in zona glomerulosa; its hypoexpression promotes aldosterone-dependent mineralocorticoid receptor transcriptional activity and hyperexpression suppresses aldosterone biosynthesis by adrenal cells. In conclusion, an extremely rare CASZ1 variant was identified in a woman with bilateral PA. The functional characterization of the CASZ1 p.(Asp638His) variant might reinforce its role as a new monogenic cause of PA. Presentation: 6/3/2024

Disclosure: M.A. Grytaas: None. P. Methlie: None. I. Marinelli: None. E. Zavala: None. M. Øksnes: None. T. Upton: None. K. Simunkova: None. D.A. Vassiliadi: None. K. Løvås: None. S. Bensing: None. I. Botusan: None. K. Berinder: None. G.M. Russell: None. G. Ueland: None. O. Kampe: None. S. Tsagarakis: None. S.L. Lightman: None. E.S. Husebye: None. Background: Primary aldosteronism (PA) is the most common cause of secondary hypertension but is grossly underdiagnosed. Early detection, accurate discrimination between unilateral and bilateral PA and appropriate treatment are vital to prevent cardiovascular and renal complications. The current workup however is a cumbersome, multistep process that may not detect dynamic aldosterone variability or nocturnal hypersecretion. Furthermore, subtype determination with adrenal venous sampling is invasive and technically challenging. Novel dynamic 24-hour steroid profiling may represent a major step forward in the diagnostics and subtyping of PA. Aim: To assess 24-hour rhythmicity of aldosterone and metabolites in PA, and to develop a novel dynamic diagnostic tool to discriminate PA from healthy subjects (HS), using tissue microdialysis. Material and methods: Twenty-minute frequency microdialysis fractions were collected over 24 hours from 64 ambulatory patients with PA (26 bilateral, 24 unilateral, 14 with undetermined subtype) using the U-Rhythm sampler followed by multiplex hormone assay liquid chromatography tandem mass spectrometry (LC-MS/MS). Sixteen patients subsequently treated with adrenalectomy for unilateral PA had additional postoperative samplings. Microdialysis samplings from 214 HS were used as controls. We calculated statistical distributions of dynamic biomarkers of abnormality, and developed a machine learning classifier that discriminates PA from HS. Results: Although there were large interindividual variations, PA patients did show a disturbed circadian rhythmicity of aldosterone compared with HS, including some with multiple very high ultradian spikes. Unilateral PA had higher aldosterone spikes and more disturbed rhythmicity compared with bilateral PA. A profound reduction of aldosterone levels and normalisation of rhythmicity was seen post adrenalectomy. Applying a Random Forest classifier in a subgroup of 20 PA patients, 82% specificity and 85% sensibility were achieved to discriminate PA from HS. Our analysis also suggests 18-hydroxycortisol as the most discriminative dynamic biomarker. Conclusions: We demonstrate for the first time circadian and ultradian rhythms of aldosterone in a large cohort of PA compared with HS. Based on our preliminary results, dynamic 24-hour samplings may provide a novel method for diagnosing and subtyping PA, and assess biochemical cure after adrenalectomy. Presentation: Thursday, June 15, 2023

The Potential Clinical Application of a Lower Bilateral Adrenal LIMB Width Ratio (L/RW) in Patients with Bilateral Primary Hyperaldosteronism

INTRODUCTION: Primary aldosteronism (PA) is characterized by the autonomous production of aldosterone, usually from an aldosterone producing adenoma in one adrenal gland or idiopathic hyperaldosteronism, with bilateral adrenal lesions. It has been suggested that aldosterone overproduction, hypokalemia, or the complication of subclinical hypercortisolism (SH) in patients with PA, are related to impaired glucose homeostasis and insulin resistance. However, the true contributions of these factors to disturbances of carbohydrate metabolism in PA have not been investigated thoroughly from a large-scale epidemiologic viewpoint. In the present study, the true prevalence of glucose intolerance in more than 2000 patients with PA and its association with aldosterone concentration, hypokalemia, and SH were studied in a multicenter collaborative study. METHODS: The prevalence of diabetes was determined in 2210 patients with PA (diagnosed or HbA1c ≥6.5%, NGSP) and compared with that of the Japanese general population from the National Survey of the Ministry of Health, Labour and Welfare in 2016, according to age and sex. In 1386 patients with PA and clear laterality (unilateral or bilateral), the effects of plasma aldosterone concentration (PAC), hypokalemia (<3.5 mEq/L), suspected SH (serum cortisol ≥1.8 μg/dL after 1-mg dexamethasone suppression test) and PA laterality on the prevalence of diabetes or prediabetes (5.7%≤HbA1c<6.5%) were examined. RESULTS: Of the 2210 patients with PA, 477 (21.6%) had diabetes, this prevalence of being higher than that of the general population (12.1%) or in 10 year cohorts aged 30 to 69 years. According to the χ2 test, diabetes was present significantly more frequently in PA patients with suspected SH (26.8%) than in those with F-1mgDST <1.8 μg/dL (16.9%; p=0.001). When using logistic regression analysis, it was found that age, sex, BMI, and F-1mgDST ≥1.8 μg/dL were significant contributing factors to the presence of diabetes, whereas laterality of PA was not a significant factor. Despite more active PA profiles (e.g. higher PAC, lower potassium concentrations) in unilateral than bilateral PA, BMI and HbA1c values were significantly higher in bilateral PA. PA laterality had no effect on prevalence of diabetes; however, prevalence of prediabetes was significantly higher in bilateral than unilateral PA. CONCLUSIONS: Individuals with PA have a high prevalence of diabetes, which is associated mainly with SH. The prevalence of prediabetes is greater for bilateral than unilateral PA, suggesting a unique metabolic cause of bilateral PA. SUPPORT: This research was supported by the Japan Agency for Medical Research and Development (AMED) for the Practical Research Project for Rare/Intractable Disease.

Primary aldosteronism (PA), a common cause of secondary hypertension, has a higher risk of cardiovascular complications than essential hypertension. To determine specific treatment for PA, subtype classification by adrenal venous sampling (AVS) is used. Sometimes, bilateral adrenal vein cannulation cannot be successfully performed. Previous studies have tried to use the data from unilateral adrenal vein cannulation, namely ipsilateral ratio (IR) and contralateral ratio (CR) in terms of aldosterone level, to interpret lateralization of aldosterone secretion. However, the cut-off values are still inconclusive. The objective of our study was to determine diagnostic performance using IR and CR in terms of adenoma location to identify functioning adrenal adenoma in patients with PA. Methods: The PA patients with unilateral adrenal adenoma who underwent AVS were included. The exclusion criteria were unsuccessful bilateral AVS or equivocal lateralization index (LI), i.e., values between 3 and 4. Successful AVS was assessed by sensitivity index, defined by adrenal vein/inferior vena cava (IVC) cortisol ratio of more than 5. The LI was calculated by dividing the higher aldosterone/cortisol ratio (dominant side) by the lower aldosterone/cortisol ratio (non-dominant side) obtained from adrenal vein samples. The LI of more than 4 indicated unilateral PA and those of less than 3 indicated bilateral PA. The IR was aldosterone/cortisol ratio at the side of adenoma divided by aldosterone/cortisol ratio at IVC. The CR was aldosterone/cortisol ratio at the side contralateral to the adenoma divided by aldosterone/cortisol ratio at IVC. Area under the receiver operating characteristic (ROC) curve was used to determine the diagnostic performance. The cut-off values giving the best sensitivity and specificity were determined. Results: Forty-three patients were included for analysis. Most patients (69.8%) were female with mean onset of hypertension at the age of 40.8±8.8years (SD). Median plasma aldosterone concentration and plasma aldosterone/renin activity ratio were 59.0 (IQR 44.2, 97.4) ng/dL and 1,020 (IQR 235, 4257), respectively. Thirty-five patients had unilateral PA, 7 patients had bilateral adrenal hyperplasia and 1 patient had unilateral adrenal hyperplasia. The area under ROC curve for identifying patients with functioning adrenal adenoma was 0.92 (95% CI; 0.81-1.00) when using IR and 0.78 (95% CI; 0.56-0.98) when using CR. The IR with the cut-off value of 1.2 had 89% sensitivity and 88% specificity. The CR with the cut-off value of 0.3 had 80% sensitivity and 75% specificity. Conclusion: The IR could be used to identify the functioning adrenal adenoma in PA patients with high accuracy.

Primary aldosteronism (PA) is associated with a higher prevalence of abdominal aortic calcification (AAC). Unilateral and bilateral PA are the most common subtypes of PA. However, no studies have addressed the difference in the prevalence of AAC between the two subtypes. In addition to aldosterone, parathyroid hormone (PTH), an important regulator of calcium metabolism, was also reported to be elevated in individuals with unilateral PA. Therefore, we hypothesized that the prevalence of AAC may be higher in individuals with unilateral PA, which may be related to the plasma aldosterone concentration (PAC) and PTH levels. We included 156 PA patients who underwent adrenal venous sampling and 156 with essential hypertension (EH) matched by age and sex. Of the former, 76 were diagnosed with unilateral PA, and 80 were diagnosed with bilateral PA. The aortic calcification index (ACI) presented the severity of AAC and was measured by adrenal computed tomography scan. Our results showed that compared with the EH group, the prevalence and severity of AAC were higher in PA patients (32.7 vs. 19.6%; 4.32 ± 3.61% vs. 2.53 ± 2.42%, respectively). In the PA subgroup analysis, unilateral PA was associated with a higher and more severe AAC than bilateral PA (40.7 vs. 25.0%; 5.12 ± 4.07% vs. 3.08 ± 2.34%, respectively). Moreover, PAC and PTH levels were higher in individuals with unilateral PA than in those with bilateral PA (P < 0.05). After risk adjustment, multivariate regression analysis revealed that PAC and PTH were positively-associated with AAC in patients with PA (P < 0.05). In conclusion, unilateral PA patients exhibited a higher prevalence of AAC and more severe AAC due to elevated PAC and PTH levels.

Background: Primary aldosteronism (PA) is a common cause of endocrine hypertension. Although adrenal venous sampling (AVS) is the gold standard for subtype classification, it is available in limited specialized centers. The aim of the study was to investigate the clinical significance of cosyntropin (ACTH) stimulation test for subtype classification in PA. Design and Methods: Sixty patients with PA who underwent ACTH stimulation test were studied. The subjects were diagnosed as having either unilateral (n = 41) or bilateral PA (n = 19) based upon AVS, adrenal scintigraphy, and/or adrenal surgery. We evaluated the diagnostic significance of ACTH stimulation test in differentiating unilateral PA from bilateral PA. Results: Peak PAC (P < 0.01) and peak PAC/cortisol (P < 0.05) after ACTH stimulation were significantly higher in patients with unilateral PA than those with bilateral PA. Peak PAC-basal PAC (ΔPAC) was higher in patients with unilateral PA than those with bilateral PA, although the difference was not statistically significant. Receiver operating characteristic curve analysis for the diagnosis of unilateral PA showed a peak PAC value of 403 pg/ml had a sensitivity of 70.7% and specificity of 79.0%, and a value of 596 pg/ml had a sensitivity of 46.3% and specificity of 100%. A peak PAC/cortisol value of 19.7 (cortisol, mcg/dl) had a sensitivity of 58.5% and specificity of 89.5%, and a value of 30.5 had a sensitivity of 26.8% and specificity of 100%. Conclusions: ACTH stimulation test could discriminate between unilateral and bilateral PA and is useful in selecting the patients who should undergo AVS before surgery.

Background: Metabolic syndrome (MetS) is a common comorbidity associated with hypertension that occurs more often in primary aldosteronism (PA). Our work aims to investigate the prevalence of MetS and its determinants in unilateral PA and bilateral PA, as confirmed by adrenal venous sampling (AVS). Methods: This was a retrospective, cross-sectional study. We investigated metabolic indicators in 160 cases of PA, categorized by AVS—82 with unilateral PA and 78 with bilateral PA. A control group of 80 non-PA patients with essential hypertension, matched for age and sex, was also included. Results: Unilateral PA had a higher aldosterone–renin ratio and lower serum potassium levels than bilateral PA. Nevertheless, bilateral PA exhibited a higher prevalence of MetS (41% vs. 30.5%; p = 0.001), obesity, BMI, LDL hypercholesterolemia, and hypertriglyceridemia than unilateral PA. Conclusions: Bilateral PA presents a greater incidence of MetS than unilateral PA, in spite of the latter showing a higher aldosterone–renin ratio and lower serum potassium levels. The results suggest that the mechanisms underlying MetS may differ between unilateral and bilateral PA.

To assess the association between polymorphisms of rs3740835(C/A) and rs2604204(A/C) in KCNJ5 gene with the susceptibility to unilateral and bilateral primary aldosteronism (PA). A total of 1043 subjects were studied, which included 83 unilateral PA patients,142 bilateral PA patients and 818 essential hypertensive(EH) patients. The polymorphism of KCNJ5 gene at rs3740835(C/A) and rs2604204(A/C) position were analyzed with a TaqMan genotyping technique. Frequencies of A allele and AA+AC genotype at rs3740835(C/A) in unilateral PA group were significantly higher than EH group (P < 0.05). However, the above frequencies did not show a statistical significance between bilateral PA group and EH group (P > 0.05). No statistical difference was detected in the distribution of alleles or genotypes at rs2604204 (A/C) between unilateral PA and EH group or between bilateral PA and EH group. Haplotypic frequencies of C-A and A-A in unilateral PA group were significantly higher and lower than EH group, respectively. However, there was no statistical difference in the haplotype distribution between bilateral PA and EH groups. Rs3740835(C/A) polymorphism may be associated with unilateral PA but not with bilateral PA. rs2604204(A/C) polymorphism is not associated with either unilateral or bilateral PA. Haplotype C-A and A-A may respectively be susceptibility factor and protective factor for unilateral PA. No haplotype has been found to associate with bilateral PA.