Inherited forms of mineralocorticoid hypertension

Mineralocorticoid receptor antagonist monotherapy in pediatric non-classical 11β-hydroxylase deficiency

OBJECTIVES

Congenital adrenal hyperplasia (CAH) is an uncommon genetic disorder which affects cortisol production in the adrenal glands. It is usually treated with glucocorticoids. We present a case of non-classical CAH caused by the partial deficiency of 11 beta-hydroxylase (11βOH) which was treated with aldosterone antagonist (eplerenone) monotherapy.

CASE PRESENTATION

An adolescent male was diagnosed with 11 beta-hydroxylase deficiency (11βOHD) at 13 years of age when he presented with hypertension, fatigue and headaches. He was initially treated with glucocorticoids, but requested an alternative therapy. Eplerenone was commenced at 25 mg with subsequent dose increases to 100 mg daily. His hypertension was controlled on this regimen, achieving a 24 h average blood pressure of 124/81 mmHg.

CONCLUSIONS

CAH caused by 11βOHD is a known cause of hypertension. It is usually managed with glucocorticoids, and antihypertensives are added if blood pressure remains uncontrolled. In this case, glucocorticoid therapy was not tolerated and treatment with aldosterone antagonist monotherapy was effective in controlling his hypertension.

Report on three cases of familial primary aldosteronism type IV

Primary aldosteronism is the most common cause of secondary hypertension, which is caused by increased aldosterone secretion in the adrenal cortex and contains many subtypes, among which familial hyperaldosteronism is relatively rare. Familial hyperaldosteronism can be divided into four subtypes based on its clinical manifestations and mutated genes: FH-I , FH-II , FH-III , and FH-IV . This article reports on three patients with FH-IV: a mother and her two sons. They were diagnosed with hypertension in other hospitals, and hypokalemia was found during hospitalization in our department. Diltiazem and terazosin were used for elution for 1 month. Renin and aldosterone levels in standing or supine positions improved, and the aldosterone-to-renin ratio was positive. Primary aldosteronism was diagnosed based on improved saline and captopril inhibition tests. As the three patients were blood-related immediate family members, gene screening was performed, diagnosing them with FH-IV . This article reports the clinical characteristics of the three cases in combination with related literature to improve the understanding of FH-IV .

A rare case of steroid 11 beta-hydroxylase deficiency in a child revealed by acute pulmonary edema

We report the case of a 5-year-old boy diagnosed with congenital adrenal hyperplasia due to 11-hydroxylase deficiency, revealed by disorders of sex development (DSD) and acute pulmonary edema due to severe hypertension. We considered the diagnosis based on biological and radiological examinations. The sociocultural background and the delayed diagnosis had a significant impact on the therapeutic decisions. All babies should be screened for 11 beta-hydroxylase deficiency, there should be specialized and interdisciplinary medical centers, and early detection is essential to avoiding serious complications of this disease.

Therapeutic management of congenital forms of endocrine hypertension

Congenital forms of endocrine hypertension are rare and potentially life-threatening disorders, primarily caused by genetic defects affecting adrenal steroid synthesis and activation pathways. These conditions exhibit diverse clinical manifestations, which can be distinguished by their unique molecular mechanisms and steroid profiles. Timely diagnosis and customized management approach are crucial to mitigate unfavorable outcomes associated with uncontrolled hypertension and other related conditions. Treatment options for these disorders depend on the distinct underlying pathophysiology, which involves specific pharmacological therapies or surgical adrenalectomy in some instances. This review article summarizes the current state of knowledge on the therapeutic management of congenital forms of endocrine hypertension, focusing on familial hyperaldosteronism (FH), congenital adrenal hyperplasia, apparent mineralocorticoid excess, and Liddle syndrome. We provide an overview of the genetic and molecular pathogenesis underlying each disorder, describe the clinical features, and discuss the various therapeutic approaches available and their risk of adverse effects, aiming to improve outcomes in patients with these rare and complex conditions.

Clinical and genetic characteristics of the patients with hypertension and hypokalemia carrying a novel SCNN1A mutation

The objective of this study was to clinically and genetically characterize a pedigree with Liddle syndrome (LS). A LS pedigree comprising with one proband and seven family members was enrolled. The subjects' symptoms, laboratory results and genotypes were analyzed. Peripheral venous samples were collected from the subjects, and genomic DNA was extracted. DNA library construction and exome capture were performed on an Illumina HiSeq 4000 platform. The selected variant sites were validated using Sanger sequencing. The mutation effects were investigated using prediction tools. The proband and her paternal male family members had mild hypertension, hypokalemia and muscle weakness, including the absence of low renin and low aldosterone. Genetic analysis revealed that the proband carried a compound heterozygous mutation in SCNN1A, a novel heterozygous mutation, c.1130T > G (p.Ile377Ser) and a previously characterized polymorphism, c.1987A > G (p.Thr633Ala). The novel mutation site was inherited in an autosomal dominant manner and was predicted by in silico tools to exert a damaging effect. Alterations in the SCNN1A domain were also predicted by protein structure modeling. After six months of follow-up, treatment had significantly improved the patient's limb weakness and electrolyte levels. The novel mutation c.1130T > G of the SCNN1A gene was detected in the pedigree with LS. The clinical manifestations of the pedigree were described, which expand the phenotypic spectrum of LS. This result of this study also emphasizes the value of genetic testing for diagnosing LS.

Clinical and Genetic Analysis of a Patient With Coexisting 17a-Hydroxylase/17,20-Lyase Deficiency and Moyamoya Disease

17a-Hydroxylase/17,20-lyase deficiency (17OHD) is caused by pathogenic mutations in CYP17A1. Female patients present with hypertension, hypokalemia, and sexual infantilism while males present with sex development disorder. Moyamoya disease (MMD) is a chronic cerebrovascular disease that frequently results in intracranial ischemia or hemorrhage. The present study describes a case of 17OHD and MMD in a 27-year-old phenotypically female (46, XY) patient and discusses the clinical features and characteristics of her genetic defect. Clinical, hormonal, radiological, and genetic analyses were performed and blood samples were collected for whole-exome sequencing (WES). The results of the WES revealed a homozygous intronic mutation (c.297+2T>C) in CYP17A1, which led to combined 17a-hydroxylase/17,20-lyase deficiency, as well as novel variants in PCNT and CNOT3 that might lead to MMD. To our knowledge, this study is the first to describe 17OHD accompanied by MMD. While several cases have previously described patients with 17OHD with histories of cerebral hemorrhage or cerebral ischemia, a correlation in genetic levels between 17OHD and MMD was not found. The risk of cerebrovascular accidents should be considered in patients with 17OHD and hypertension. Cerebrovascular examination in patients with 17OHD may be beneficial for the prevention of life-threatening intracranial vascular disease.

A Novel Frame-Shift Mutation in SCNN1B Identified in a Chinese Family Characterized by Early-Onset Hypertension

Background

Liddle syndrome is a form of monogenic hypertension caused by mutations in the three homologous subunits of the epithelial sodium channels (ENaCs), α, β, and γ. It is characterized by early-onset refractory hypertension, hypokalemia, low renin activity, and hypoaldosteronism. In this study, we report a novel frame-shift mutation in SCNN1B responsible for Liddle syndrome in a Chinese family.

Methods

DNA samples were collected from all participants. Whole-exome sequencing was performed in the proband to detect possible causative variants. Sanger sequencing was then conducted in the other family members to verify the candidate variant, and in 100 patients with hypertension and 100 normotensive controls to exclude population genetic polymorphism.

Results

We identified a novel frame-shift mutation (c.1691_1693delinsG) in SCNN1B that was responsible for Liddle syndrome in this family. This mutation leads to the substitution of Arg in place of Gln at codon site 564 and generates a new stop codon at 592, influencing the crucial PY motif and resulting in reduced inactivation of the ENaCs. Aside from the proband, eight family members carried the mutation. Intra-familial phenotypic heterogeneity was observed in the blood pressure and serum potassium levels. Amiloride therapy combined with a low sodium diet is effective to alleviate the symptoms of patients with Liddle syndrome.

Conclusion

c.1691_1693delinsG, a novel frame-shift mutation in the β subunit of ENaC, was identified in a Chinese family with Liddle syndrome by whole-exome sequencing. Phenotypic heterogeneity can make diagnosis of Liddle syndrome difficult on the basis of clinical or biochemical characteristics alone. Genetic analysis is a useful tool allowing timely and accurate diagnosis of Liddle syndrome and playing a guiding role in precise treatment of the disease.

Pathophysiology of bilateral hyperaldosteronism

PURPOSE OF REVIEW

Renin-independent aldosterone production from one or both affected adrenal(s), a condition known as primary aldosteronism (PA), is a common cause of secondary hypertension. In this review, we aimed to summarize recent findings regarding pathophysiology of bilateral forms of PA, including sporadic bilateral hyperaldosteronism (BHA) and rare familial hyperaldosteronism.

RECENT FINDINGS

The presence of subcapsular aldosterone synthase (CYP11B2)-expressing aldosterone-producing micronodules, also called aldosterone-producing cell clusters, appears to be a common histologic feature of adrenals with sporadic BHA. Aldosterone-producing micronodules frequently harbor aldosterone-driver somatic mutations. Other potential factors leading to sporadic BHA include rare disease-predisposing germline variants, circulating angiotensin II type 1 receptor autoantibodies, and paracrine activation of aldosterone production by adrenal mast cells. The application of whole exome sequencing has also identified new genes that cause inherited familial forms of PA.

SUMMARY

Research over the past 10 years has significantly improved our understanding of the molecular pathogenesis of bilateral PA. Based on the improved understanding of BHA, future studies should have the ability to develop more personalized treatment options and advanced diagnostic tools for patients with PA.

Metabolic syndrome and cardiovascular morbidity in patients with congenital adrenal hyperplasia

Since the introduction of glucocorticoid (GC) replacement therapy, congenital adrenal hyperplasia (CAH) is no longer a fatal disease. The development of neonatal screening programs and the amelioration of GC treatment strategies have improved significantly life expectancy in CAH patients. Thanks to these achievements, CAH patients are now in their adulthood, but an increased incidence of cardiovascular risk factors has been reported compared to general population in this stage of life. The aim of CAH treatment is to both prevent adrenal insufficiency and suppress androgen excess; in this delicate balance, under- as well as overtreatment might be equally harmful to long-term cardiovascular health. This work examines the prevalence of metabolic features and cardiovascular events, their correlation with hormone levels and GC replacement regimen in CAH patients and focuses on precocious markers to early detect patients at higher risk and new potential treatment approaches.

Apparent mineralocorticoid excess caused by novel compound heterozygous mutations in HSD11B2 and characterized by early-onset hypertension and hypokalemia

PURPOSE

Apparent mineralocorticoid excess (AME) is an ultrarare autosomal recessive disorder resulting from deficiency of 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) caused by mutations in HSD11B2. The purpose of this study was to identify novel compound heterozygous HSD11B2 mutations in a Chinese pedigree with AME and conduct a systematic review evaluating the AME clinical features associated with HSD11B2 mutations.

METHODS

Next-generation sequencing was performed in the proband, and Sanger sequencing was used to identify candidate variants in family members, 100 hypertensives, and 100 healthy controls. A predicted structure of 11βHSD2 was constructed by in silico modeling. A systematic review was used to identify cases of HSD11B2-related AME. Data for genotyping and clinical characterizations and complications were extracted.

RESULTS

Next-generation sequencing showed novel compound heterozygous mutations (c.343_348del and c.1099_1101del) in the proband with early-onset hypertension and hypokalemia. Sanger sequencing verified the monoallelic form of the same mutations in five other relatives but not in 100 hypertensives or 100 healthy subjects. In silico structural modeling showed that compound mutations may simultaneously perturb the substrate and coenzyme binding pocket. A systematic review of 101 AME patients with 54 HSD11B2 mutations revealed early-onset hypertension, hypokalemia and homozygous mutations as common features. The homozygous HSD11B2 mutations correlated with low birth weight (r = 0.285, P = 0.02).

CONCLUSIONS

We report novel compound heterozygous HSD11B2 mutations in a Chinese teenager with early-onset hypertension, and enriched genotypic and phenotypic spectrums in AME. Genetic testing helps early diagnosis and treatment for AME patients, which may avoid target organ damage.

Diagnosis and Management of Endocrine Hypertension in Children and Adolescents

Hypertension in childhood and adolescence has increased in prevalence. Interest in the disease was raised after the 2017 clinical practice guidelines of the American Academy of Paediatrics on the definition and classification of paediatric hypertension. Among the secondary causes of paediatric hypertension, endocrine causes are relatively rare but important due to their unique treatment options. Excess of catecholamine, glucocorticoids and mineralocorticoids, congenital adrenal hyperplasia, hyperaldosteronism, hyperthyroidism and other rare syndromes with specific genetic defects are endocrine disorders leading to paediatric and adolescent hypertension. Adipose tissue is currently considered the major endocrine gland. Obesity-related hypertension constitutes a distinct clinical entity leading to an endocrine disorder. The dramatic increase in the rates of obesity during childhood has resulted in a rise in obesity-related hypertension among children, leading to increased cardiovascular risk and associated increased morbidity and mortality. This review presents an overview of pathophysiology and diagnosis of hypertension resulting from hormonal excess, as well as obesity-related hypertension during childhood and adolescence, with a special focus on management.

Molecular Basis of Primary Aldosteronism and Adrenal Cushing Syndrome

This review reports the main molecular alterations leading to development of benign cortisol- and/or aldosterone-secreting adrenal tumors. Causes of adrenal Cushing syndrome can be divided in 2 groups: multiple bilateral tumors or adenomas secreting cortisol. Bilateral causes are mainly primary pigmented nodular adrenocortical disease, most of the time due to PRKAR1A germline-inactivating mutations, and primary bilateral macronodular adrenal hyperplasia that can be caused in some rare syndromic cases by germline-inactivating mutations of MEN1, APC, and FH and of ARMC5 in isolated forms. PRKACA somatic-activating mutations are the main alterations in unilateral cortisol-producing adenomas. In primary hyperaldosteronism (PA), familial forms were identified in 1% to 5% of cases: familial hyperaldosteronism type I (FH-I) due to a chimeric CYP11B1/CYP11B2 hybrid gene, FH-II due to CLCN-2 germline mutations, FH-III due to KCNJ5 germline mutations, FH-IV due to CACNA1H germline mutations and PA, and seizures and neurological abnormalities syndrome due to CACNA1D germline mutations. Several somatic mutations have been found in aldosterone-producing adenomas in KCNJ5, ATP1A1, ATP2B3, CACNA1D, and CTNNB1 genes.

In addition to these genetic alterations, genome-wide approaches identified several new alterations in transcriptome, methylome, and miRnome studies, highlighting new pathways involved in steroid dysregulation.

Overview of Monogenic Forms of Hypertension Combined With Hypokalemia

Hypertension is an important risk factor in many conditions and creates a heavy burden of disease and mortality globally. Polygenic hypertension is the most common form; however, it is increasingly recognized that monogenic hypertension is not rare, especially in patients with electrolyte disorders. Single genetic alterations are associated with plasma volume expansion and catecholamines/sympathetic excess with simultaneously increased potassium excretion in the urine and potassium intracellular shift. Early-onset refractory hypertension and profound hypokalemia are characteristics of monogenic hypertension. However, accumulated evidence shows the existence of phenotypic heterogeneity in monogenic hypertension meaning that, even for mild symptoms, clinicians cannot easily exclude the possibility of monogenic hypertension. Genetic, epigenetic and non-genetic factors are all possible mechanisms influencing phenotypic diversity. Genetic sequencing is a precise and efficient method that can broaden the mutant gene spectrum of the disease and is very helpful for understanding the pathophysiology of monogenic hypertension. Genetic sequencing, along with biochemical tests and imaging modalities, is essential for the early diagnosis and targeted management of monogenic hypertension to avoid long-term catastrophic complications.

Steroid metabolism gene variants and their genotype-phenotype correlations in Chinese early-onset hypertension patients

The genetic factors related to early-onset hypertension are largely unknown. This study aimed to determine the spectrum of steroid metabolism gene variants and the clinical relationships of these variants to phenotypes in Chinese patients with early-onset hypertension. A total of 306 consecutive early-onset hypertensive patients were recruited. All coding exons and flanking intronic regions of KCNJ5, CYP11B1, and CYP17A1 were sequenced. Long-distance polymerase chain reaction was used to search for a CYP11B1/CYP11B2 chimeric gene. Pedigree investigations and genotype-phenotype analyses were performed for patients with rare variants. Nine rare variants were detected in eight patients (2.6%), but no CYP11B1/CYP11B2 chimeric gene was identified. One patient and two of her siblings were found to carry compound heterozygous mutations (C183Y and T390R) in CYP17A1 and were eventually diagnosed with atypical congenital adrenal hyperplasia. Patients with rare variants had younger ages of onset [17 (16, 20) vs. 30 (23, 35) years old, p = 0.010] and higher systolic blood pressure (148.5 ± 9.6 vs. 137.9 ± 17.8 mmHg, p = 0.021) than those without rare variants. Additionally, the patients and their relatives carrying rare variants exhibited increased serum free corticosterone [230.4 (7.4, 533.0) vs. 1.9 (0.9, 6.7)ng/ml, p = 0.001] and 11-deoxycorticosterone [16.16 (0.59, 33.23) vs. 0.77 (0.41, 0.96)ng/ml, p = 0.038] levels. Genetic testing is useful for the etiologic diagnosis of early-onset hypertension. Rare variants in steroid metabolism genes were associated with more severe clinical expression and abnormal circulating steroid metabolites in patients with early-onset hypertension.

Typical characteristics of children with congenital adrenal hyperplasia due to 11β-hydroxylase deficiency: a single-centre experience and review of the literature

Background 11β-hydroxylase deficiency (11βOHD) is a rare disease representing the second most common cause of congenital adrenal hyperplasia (CAH) (5-8%) with an incidence of about 1:100,000. In contrast to 21-hydroxylase deficiency (21OHD), 11βOHD is not included in neonatal screening programmes. The objective of this study was to demonstrate the typical features of male patients with 11βOHD. Methods Clinical, biochemical and radiological data of patients with 11βOHD were analysed in this retrospective single-centre analysis. Results Six male patients of four unrelated families with 11βOHD were identified (0.1-13.5 years of chronological age [CA] at diagnosis). The predominant symptoms were arterial hypertension, tall stature and precocious pseudopuberty. Bone ages (BAs) were remarkably advanced at diagnosis in four index patients (median difference BA-CA: 5.5 years, range 1.5-9.2 years). Homozygous mutations were identified in exon 7 (c.1179_1180dupGA [p.Asn394Argfs*37]) and exon 8 (c.1398+2T>C) of the CYP11B1 gene leading both to a complete loss of function. The latter mutation has not yet been described in databases. 11βOHD was identified by the measurement of 11-deoxycortisol in a newborn screening card of one patient retrospectively. Testicular adrenal rest tumours (TARTs) were detected in three patients at 3.7 years, 11 years and 14.4 years. Conclusion The diagnosis of CAH due to 11βOHD is delayed and should be suspected in children with arterial hypertension, tall stature and precocious pseudopuberty. Patients may develop TARTs as early as infancy. 11βOHD should be included in newborn screening programmes, at least in newborns of index families, to allow early diagnosis and the start of treatment to reduce morbidity.

The patient with metabolic alkalosis

Metabolic alkalosis defined by the increase of both plasma HCO3- level (>26 mmol/L) and blood arterial pH (>7.43) is quite frequent and usually accompanied by hypokalemia. Its pathogenesis requires both the generation of alkalosis and its maintenance. Generation may be due to excessive hydrogen ion loss by the gastrointestinal tract (e.g. vomiting) or by the kidney (e.g. use of loop diuretics) or may be due to exogenous base gain. Maintenance reflects the inability of the kidney to excrete the excess of bicarbonate because of hypovolemia, chloride depletion, hypokalemia, hyperaldosteronism, renal failure or a combination of these factors. The evaluation of volemic status and measurement of urinary Cl- and plasma levels of renin and aldosterone are crucial to identify the cause(s) of metabolic alkalosis. The cornerstone of treatment is the correction of existing depletions and the prevention of further losses. In vomiting-induced chloride depletion alkalosis, infusion of potassium chloride restores the excretion of bicarbonate by the kidney.

Liddle syndrome misdiagnosed as primary aldosteronism resulting from a novel frameshift mutation of SCNN1B

Liddle syndrome (LS), a monogenetic autosomal dominant disorder, is mainly characterized by early-onset hypertension and hypokalemia. Clinically, misdiagnosis or missing diagnosis is common, since clinical phenotypes of LS are variable and nonspecific. We report a family with misdiagnosis of primary aldosteronism (PA), but identify as LS with a pathogenic frameshift mutation of the epithelial sodium channel (ENaC) β subunit. DNA samples were collected from a 32-year-old proband and 31 other relatives in the same family. A designed panel including 41 genes associated with monogenic hypertension was screened using next-generation sequencing. The best candidate disease-causing variants were verified by Sanger sequencing. Genetic analysis of the proband revealed a novel frameshift mutation c.1838delC (p.Pro613Glnfs*675) in exon 13 of SCNN1B. This heterozygous mutation involved the deletion of a cytosine from a string of three consecutive cytosines located at codons 612 to 613 and resulted in deletion of the crucial PY motif and elongation of the β-ENaC protein. The identical mutation was also found in 12 affected family members. Amiloride was effective in alleviating LS for patients. There were no SCNN1A or SCNN1G mutations in this family. Our study emphasizes the importance of considering LS in the differential diagnosis of early-onset hypertension. The identification of a novel frameshift mutation of SCNN1B enriches the genetic spectrum of LS and has allowed treatment of this affected family to prevent severe complications.

Hypokalemia: a clinical update

Hypokalemia is a common electrolyte disturbance, especially in hospitalized patients. It can have various causes, including endocrine ones. Sometimes, hypokalemia requires urgent medical attention. The aim of this review is to present updated information regarding: (1) the definition and prevalence of hypokalemia, (2) the physiology of potassium homeostasis, (3) the various causes leading to hypokalemia, (4) the diagnostic steps for the assessment of hypokalemia and (5) the appropriate treatment of hypokalemia depending on the cause. Practical algorithms for the optimal diagnostic, treatment and follow-up strategy are presented, while an individualized approach is emphasized.

Liddle Syndrome: Review of the Literature and Description of a New Case

Liddle syndrome is an inherited form of low-renin hypertension, transmitted with an autosomal dominant pattern. The molecular basis of Liddle syndrome resides in germline mutations of the SCNN1A, SCNN1B and SCNN1G genes, encoding the α, β, and γ-subunits of the epithelial Na⁺ channel (ENaC), respectively. To date, 31 different causative mutations have been reported in 72 families from four continents. The majority of the substitutions cause an increased expression of the channel at the distal nephron apical membrane, with subsequent enhanced renal sodium reabsorption. The most common clinical presentation of the disease is early onset hypertension, hypokalemia, metabolic alkalosis, suppressed plasma renin activity and low plasma aldosterone. Consequently, treatment of Liddle syndrome is based on the administration of ENaC blockers, amiloride and triamterene. Herein, we discuss the genetic basis, clinical presentation, diagnosis and treatment of Liddle syndrome. Finally, we report a new case in an Italian family, caused by a SCNN1B p.Pro618Leu substitution.

Congenital adrenal hyperplasia causing hypertension: an illustrative review

Congenital adrenal hyperplasia (CAH) is often considered a pediatric endocrinology condition, but we present two cases of young adults who presented with hypertension. An 18-year-old woman was found to have hypertension and hypokalemia when she presented for gonadectomy for 46, XY gonadal dysgenesis. She was subsequently found to have low cortisol, elevated progesterone, and elevated aldosterone. Genetic testing confirmed 17-alpha hydroxylase deficiency (17OHD). Her case was unique in that 17OHD usually presents with hypoaldosteronism. We also present the case of a 15-year-old man (46, XX) with resistant hypertension due to 11-beta hydroxylase deficiency (11OHD) who underwent bilateral adrenalectomy for control of hypertension. The relevant literature is reviewed including the pathophysiology, clinical presentation, and treatment of the hypertensive variants of congenital adrenal hyperplasia. We also review the unique areas of hyperaldosteronism in 17OHD and the use of bilateral adrenalectomy for control of hypertension in CAH.

Endocrine Hypertension: A Practical Approach

Elevated blood pressure resulting from few endocrine disorders (endocrine hypertension) accounts for a high proportion of cases of secondary hypertension. Although some features may be suggestive, many cases of endocrine hypertension remain silent until worked up for the disease. A majority of cases result from primary aldosteronism. Other conditions that can cause endocrine hypertension are: congenital adrenal hyperplasia, Liddle syndrome, pheochromocytomas, Cushing's syndrome, acromegaly, thyroid diseases, primary hyperparathyroidism and iatrogenic hormone manipulation. Early identification and treatment of the cause of endocrine hypertension may help to reduce morbidity and mortality related to these disorders. This article gives a comprehensive and practical approach to the diagnosis and management of endocrine hypertension.

CACNA1H Mutations Are Associated With Different Forms of Primary Aldosteronism

Primary aldosteronism (PA) is the most common form of secondary hypertension. Mutations in KCNJ5, ATP1A1, ATP2B3 and CACNA1D are found in aldosterone producing adenoma (APA) and familial hyperaldosteronism (FH). A recurrent mutation in CACNA1H (coding for Cav3.2) was identified in a familial form of early onset PA. Here we performed whole exome sequencing (WES) in patients with different types of PA to identify new susceptibility genes. Four different heterozygous germline CACNA1H variants were identified. A de novo Cav3.2 p.Met1549Ile variant was found in early onset PA and multiplex developmental disorder. Cav3.2 p.Ser196Leu and p.Pro2083Leu were found in two patients with FH, and p.Val1951Glu was identified in one patient with APA. Electrophysiological analysis of mutant Cav3.2 channels revealed significant changes in the Ca²⁺ current properties for all mutants, suggesting a gain of function phenotype. Transfections of mutant Cav3.2 in H295R-S2 cells led to increased aldosterone production and/or expression of genes coding for steroidogenic enzymes after K⁺ stimulation. Identification of CACNA1H mutations associated with early onset PA, FH, and APA suggests that CACNA1H might be a susceptibility gene predisposing to PA with different phenotypic presentations, opening new perspectives for genetic diagnosis and management of patients with PA.

Bilateral Idiopathic Adrenal Hyperplasia: Genetics and Beyond

Bilateral adrenal hyperplasia currently accounts for up to 2 thirds of cases of primary aldosteronism. As such, it represents a major opportunity for targeted medical management as opposed to unilateral surgically correctable forms of the disease. Although the majority of cases of primary aldosteronism are sporadic, bilateral adrenal hyperplasia may occur in the context of familial hyperaldosteronism where it is associated with specific germline mutations. Over the past 5 years, impressive progress has been made in our understanding of the genetic basis underlying primary aldosteronism, allowing us to identify and characterize new familial forms of the disease and to understand the mechanisms involved in the formation of aldosterone producing adenoma. In contrast, our knowledge of the genetic contribution to the development of bilateral adrenal hyperplasia, and in a larger context, to renin and aldosterone levels in the general population, is still poor. This review summarizes our current knowledge on the genetics of bilateral adrenal hyperplasia and addresses some open questions to be addressed by future research. In particular, genome-wide association studies in large populations may provide clues to understanding the genetic susceptibility underlying the development of primary aldosteronism.