Familial Hyperaldosteronism Type 3 with a Rapidly Growing Adrenal Tumor: An In Situ Aldosterone Imaging Study

Primary aldosteronism is most often caused by aldosterone-producing adenoma (APA) and bi-lateral adrenal hyperplasia. Most APAs are caused by somatic mutations of various ion channels and pumps, the most common being the inward-rectifying potassium channel KCNJ5. Germ line mutations of KCNJ5 cause familial hyperaldosteronism type 3 (FH3), which is associated with severe hyperaldosteronism and hypertension. We present an unusual case of FH3 in a young woman, first diagnosed with primary aldosteronism at the age of 6 years, with bilateral adrenal hyperplasia, who underwent unilateral adrenalectomy (left adrenal) to alleviate hyperaldosteronism. However, her hyperaldosteronism persisted. At the age of 26 years, tomography of the remaining adrenal revealed two different adrenal tumors, one of which grew substantially in 4 months; therefore, the adrenal gland was removed. A comprehensive histological, immunohistochemical, and molecular evaluation of various sections of the adrenal gland and in situ visualization of aldosterone, using matrix-assisted laser desorption/ionization imaging mass spectrometry, was performed. Aldosterone synthase (CYP11B2) immunoreactivity was observed in the tumors and adrenal gland. The larger tumor also harbored a somatic β-catenin activating mutation. Aldosterone visualized in situ was only found in the subcapsular regions of the adrenal and not in the tumors. Collectively, this case of FH3 presented unusual tumor development and histological/molecular findings.

Progress on Genetic Basis of Primary Aldosteronism

Primary aldosteronism (PA) is a heterogeneous group of disorders caused by the autonomous overproduction of aldosterone with simultaneous suppression of plasma renin activity (PRA). It is considered to be the most common endocrine cause of secondary arterial hypertension (HT) and is associated with a high rate of cardiovascular complications. PA is most often caused by a bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenoma (APA); rarer causes of PA include genetic disorders of steroidogenesis (familial hyperaldosteronism (FA) type I, II, III and IV), aldosterone-producing adrenocortical carcinoma, and ectopic aldosterone-producing tumors. Over the last few years, significant progress has been made towards understanding the genetic basis of PA, classifying it as a channelopathy. Recently, a growing body of clinical evidence suggests that mutations in ion channels appear to be the major cause of aldosterone-producing adenomas, and several mutations within the ion channel encoding genes have been identified. Somatic mutations in four genes (KCNJ5, ATP1A1, ATP2B3 and CACNA1D) have been identified in nearly 60% of the sporadic APAs, while germline mutations in KCNJ5 and CACNA1H have been reported in different subtypes of familial hyperaldosteronism. These new insights into the molecular mechanisms underlying PA may be associated with potential implications for diagnosis and therapy.

A systematic review of pathophysiology and management of familial hyperaldosteronism type 1 in pregnancy

Purpose Familial hyperaldosteronism type 1 (FH-1) is a rare autosomal dominant form of primary aldosteronism, which features a marked phenotypic heterogeneity, ranging from mild to severe forms of arterial hypertension that can be complicated by stroke and cardiovascular events at a young age. As affected patients usually reach the fertile age, transmission of the disease to offspring is common. Notwithstanding this, reports of FH-1 in pregnancy are limited and there is a lack of treatment guidelines. Methods and results We searched the PubMed and EuropePMC databases with a PICO strategy to retrieve available information on management of FH-1 patients during pregnancy. We could identify seven relevant articles, which are herein reviewed. Conclusion Based on available information on pathophysiology and treatment of FH-1 in pregnancy, recommendations for the rational management of FH-1 in pregnancy are provided.

Resistant Hypertension Due to Familial Hyperaldosteronism Type III: First Report From Indian Sub-Continent

Background: Familial hyperaldosteronism type III (FH-III) is caused by germline mutations in KCNJ5 gene. FH-III presents with phenotypic variability from spironolactone-responsive hypertension to massive adrenal hyperplasia requiring bilateral adrenalectomy. Till date, seven different pathogenic mutations in KCNJ5 gene have been identified. Here we describe a sporadic FH-III case, due to a Gly151Arg mutation, first from Indian subcontinent, presenting with extremely high plasma aldosterone concentration (PAC) values, further expanding our knowledge of this rare condition. Clinical Case: A 24-year-old female, symptomatic since age of 5 years with periodic limb weakness and gradual increase in frequency of episodes over the years. Her blood pressure (BP) was recorded for first time at 9 years of age, and it was 170/110 mm Hg. On evaluation at this time, PAC was highly elevated at 1007 ng/dL and plasma renin activity (PRA) was suppressed at 0.04 ng/ml/h with aldosterone renin ratio (ARR) of 25,175 ng/dL per ng/mL/h (>20 suggestive of primary aldosteronism). CT scan demonstrated mild enlargement of bilateral adrenal glands. A presumptive diagnosis of Glucocorticoid-remediable aldosteronism was made. She was started on dexamethasone, spironolactone and nifedipine but was not improved. Dexamethasone was stopped after 1 year of initiation. Before presenting to our referral center in 2018, she was having uncontrolled hypertension with recurrent episodes of hypokalemic paralysis. She was on maximal doses on four antihypertensive agents, further increased to six agents (including spironolactone 100 mg BD), and potassium chloride supplementation (120 mEq/day). Despite this, she had a serum potassium of 2.6 mEq/L. Her biochemical investigations demonstrated that PAC was 2070 ng/dL, direct renin concentration (DRC) was 2.35 µIU/mL (PRA 0.2 ng/ml/h) and ARR was 880.9 ng/dL per µIU/mL. CT scan revealed massive bilateral adrenal hyperplasia. Genetic analysis by whole exome sequencing detected KCNJ5 (p.Gly151Arg) mutation, confirming the diagnosis of FH-III. She was subjected to bilateral adrenalectomy and she became normokalemic. Dramatic reduction in antihypertensives with BP control achieved only on amlodipine post-operatively. Genetic testing of family members was not done but they were normotensive and normokalemic. Histopathological examination revealed bilateral adrenal hyperplasia. PAC levels up to 297 ng/dL have been described previously in FH-III but our patient had exceedingly high-level of 2070 ng/dL. Conclusion: This case demonstrates florid clinical and biochemical manifestations of FH-III and gradual worsening of symptoms, consistent with progression of disease with age. It illustrates that proper investigations and treatment can lead to remission of symptoms. Further studies are warranted to elucidate the full clinical and biochemical spectrum of FH-III.

Enhanced Ca2+ signaling, mild primary aldosteronism, and hypertension in a familial hyperaldosteronism mouse model (Cacna1hM1560V/+)

Gain-of-function mutations in the CACNA1H gene (encoding the T-type calcium channel CaV3.2) cause autosomal-dominant familial hyperaldosteronism type IV (FH-IV) and early-onset hypertension in humans. We used CRISPR/Cas9 to generate Cacna1hM1560V/+ knockin mice as a model of the most common FH-IV mutation, along with corresponding knockout mice (Cacna1h−/−). Adrenal morphology of both Cacna1hM1560V/+ and Cacna1h−/− mice was normal. Cacna1hM1560V/+ mice had elevated aldosterone:renin ratios (a screening parameter for primary aldosteronism). Their adrenal Cyp11b2 (aldosterone synthase) expression was increased and remained elevated on a high-salt diet (relative autonomy, characteristic of primary aldosteronism), but plasma aldosterone was only elevated in male animals. The systolic blood pressure of Cacna1hM1560V/+ mice was 8 mmHg higher than in wild-type littermates and remained elevated on a high-salt diet. Cacna1h−/− mice had elevated renal Ren1 (renin-1) expression but normal adrenal Cyp11b2 levels, suggesting that in the absence of CaV3.2, stimulation of the renin-angiotensin system activates alternative calcium entry pathways to maintain normal aldosterone production. On a cellular level, Cacna1hM1560V/+ adrenal slices showed increased baseline and peak intracellular calcium concentrations in the zona glomerulosa compared to controls, but the frequency of calcium spikes did not rise. We conclude that FH-IV, on a molecular level, is caused by elevated intracellular Ca2+ concentrations as a signal for aldosterone production in adrenal glomerulosa cells. We demonstrate that a germline Cacna1h gain-of-function mutation is sufficient to cause mild primary aldosteronism, whereas loss of CaV3.2 channel function can be compensated for in a chronic setting.

SUN-191 The Creatinine, the Crib and the Manometer - Navigating the Labyrinth of Primary Aldosteronism

A 21-year-old Ethiopian female with a five-year history of hypertension presented to medicine clinic with headaches and fatigue for two weeks. She was hypertensive to 163/113 mmHg. She had recently moved to the US and no prior medical records were available. She had been taking an unknown antihypertensive until three weeks prior. She was found to have a creatinine of 3.49 mg/dL. Renal ultrasound revealed bilateral, small echogenic kidneys without any evidence of renal artery stenosis. An intrauterine pregnancy was also incidentally discovered. Her aldosterone level was elevated to 486 ng/dL and her renin activity was 1.3 ng/ml/hr, with a ratio of 373, diagnostic of primary aldosteronism. Due to the markedly high ratio, a saline suppression test was deemed unnecessary for confirmation. Her serum potassium was normal at 3.6 mEq, likely due to poor renal clearance. Given renal failure, a CT non-contrast of the adrenal glands was performed with normal findings. She elected to terminate the high-risk pregnancy. Based upon her young age at presentation, family history of early onset hypertension, grossly elevated aldosterone: renin ratio and unrevealing workup for a primary tumor or hyperplastic adrenals, a diagnosis of familial hyperaldosteronism was considered. She failed a month-long trial of dexamethasone therapy, therefore glucocorticoid remediable aldosteronism was excluded. She was subsequently started on spironolactone with good response. Adrenal vein sampling was considered to find a surgical target for adrenalectomy but could not be performed given worsening kidney function. After discussion with Nephrology she opted for a pre-emptive renal transplant evaluation, rather than pursuing dialysis. Genetic testing for subclassification has been negative for mutations in KCNJ5 and CACNA1H with ongoing testing for novel mutations. Primary aldosteronism (PA) usually presents with recalcitrant hypertension, hypokalemia and an elevated aldosterone: renin ratio. It is commonly attributed to adrenal adenomas or hyperplasia with familial hyperaldosteronism (FH) remaining a rare etiology. FH is sub-divided into glucocorticoid remediable, type I, and non- glucocorticoid remediable, types II – IV. The initial diagnosis of such a condition during pregnancy and in the setting of worsening kidney disease presents a diagnostic and management challenge as this precludes adrenal vein sampling and contrast imaging. Our case highlights the importance of early screening for PA and illustrates the need for updated guidelines on aldosteronism workup in the setting of ESRD and pregnancy.