A novel nonsense mutation in ARMC5 causes primary bilateral macronodular adrenocortical hyperplasia

Prevalence and main characteristics of primary aldosteronism in bilateral macronodular adrenal disease: a systematic review of the literature

CONTEXT

Bilateral macronodular adrenal disease (BMAD) typically presents with bilateral benign adrenocortical macronodules and variable cortisol excess. Anecdotal evidence suggests oversecretion of other adrenal steroids, including mineralocorticoids.

HYPOTHESIS

We hypothesized that primary aldosteronism (PA) can occur in BMAD, resulting in a distinct, more severe phenotype compared to BMAD with isolated cortisol hypersecretion or unilateral PA (uPA).

OBJECTIVE

To assess the prevalence and characteristics of PA in BMAD.

METHODS

We systematically reviewed case reports and series of BMAD patients with PA, following PRISMA guidelines. BMAD was defined by bilateral adrenal nodules ≥10 mm. PA diagnosis followed US or Japanese Endocrine Society guidelines. We compared these findings with 2 cohorts from LMU Hospital Munich: BMAD with isolated cortisol hypersecretion and uPA.

RESULTS

From 1018 articles, 18 representing 68 cases were included. Of these, 66 had BMAD with PA and 2 had BMAD with aldosterone precursor excess. The PA proportion in published BMAD series ranged from 2% to 43%. BMAD patients with PA were predominantly male (75%) and younger (median 51.5 years) than those with isolated cortisol hypersecretion (median 60.5 years, P < .01). Their median blood pressure was higher (170/100 mm Hg) compared to those with isolated cortisol hypersecretion (138/80 mm Hg) or uPA (153/94 mm Hg, P < .01). Treatment was only described in 28 cases, with 93% undergoing adrenalectomy. Clinical outcome was similar across groups post-treatment.

CONCLUSION

This review highlights the need for increased screening for PA in younger, hypertensive BMAD patients. Larger multicenter studies are needed to determine the association between these conditions, cardiovascular risk, and optimal treatment.

The mutational landscape of ARMC5 in Primary Bilateral Macronodular Adrenal Hyperplasia: an update

BACKGROUND

Primary Bilateral Macronodular Adrenal Hyperplasia (PBMAH) is a rare cause of Cushing's syndrome due to bilateral adrenocortical macronodules. Germline inactivating variants of the tumor suppressor gene ARMC5 are responsible for 20-25% of apparently sporadic PBMAH cases and 80% of familial presentations. ARMC5 screening is now routinely performed for PBMAH patients and families. Based on literature review and own observation, this study aims to give an overview of both published and unpublished ARMC5 genetic alterations and to compile the available evidence to discriminate pathogenic from benign variants.

RESULTS

146 different germline variants (110 previously published and 36 novel) are identified, including 46% missense substitutions, 45% truncating variants, 3% affecting splice sites, 4% in-frame variants and 2% large deletions. In addition to the germline events, somatic 16p loss-of-heterozygosity and 104 different somatic events are described. The pathogenicity of ARMC5 variants is established on the basis of their frequency in the general population, in silico predictions, familial segregation and tumor DNA sequencing.

CONCLUSIONS

This is the first extensive review of ARMC5 pathogenic variants. It shows that they are spread on the whole coding sequence. This is a valuable resource for genetic investigations of PBMAH and will help the interpretation of new missense substitutions that are continuously identified.

Primary bilateral macronodular adrenal hyperplasia: A rare case report of Cushing syndrome and review of literature

RATIONALE

Primary bilateral macronodular adrenal hyperplasia (PBMAH) is a rare cause of ACTH-independent Cushing syndrome (CS), accounting for <2% of CS cases. Diagnosing PBMAH can be difficult and challenging for clinicians.

PATIENT CONCERNS

We report a 52-year-old female, a patient with a history of intermittent fever for 3 years. She presented with nausea, headache, and dizziness for several days, along with fatigue, myalgia, muscle weakness, exertional dyspnea, hoarseness, spontaneous bruising over the past several months, and long-term psychological complaints. Additionally, we observed periorbital and facial edema, right lower quadrant tenderness, and abdominal striae during the examination.

DIAGNOSES

Her laboratory results showed increased cortisol and suppressed ACTH, and an abdominal CT scan revealed 2 heterogeneous masses in the adrenal glands. These findings led us to the diagnosis of PBMAH in this patient. The existence of aberrant receptors was evaluated, and the tests were negative.

INTERVENTIONS

The patient underwent left adrenalectomy and corticosteroid therapy after the surgery. Her clinical complaints improved after the surgery.

OUTCOMES

However, her dependency on corticosteroids was not transient after unilateral adrenalectomy, and she still needs glucocorticoid supplementation 1 year after surgery.

LESSONS

This patient is a case of PBMAH who presented with fever and CS symptoms and underwent unilateral adrenalectomy. Interestingly, she had suppressed cortisol levels for at least 1 year after the unilateral adrenalectomy. Therefore, we suggest further research on the most effective treatment strategies for PBMAH.

Familial bilateral macronodular adrenal hyperplasia due to a novel ARMC 5 germline mutation: Clinical status and possible association with other neoplasms

INTRODUCTION/OBJECTIVES

Mutations in the ARMC5 (armadillo repeat containing 5, OMIM 615549) gene, a putative tumor suppressor gene, have recently been identified as a common cause of sporadic and familial bilateral macronodular adrenal hyperplasia (BMAH). Familial BMAH is thought to be caused by two mutations, one germline and the other somatic, as suggested by the 2-hit theory. The objective is to describe a new mutation and develop its clinical characteristics and implications.

METHODS, RESULTS AND CONCLUSIONS

We present an affected family with 11 members carrying a novel mutation of the ARMC5 gene (NM_001288767.1): c.2162T>C p. (Leu721Pro). Two of the carriers developed clinical Cushing's syndrome (CS), two mild autonomous cortisol secretion (MACS) and one presented with autonomous cortisol secretion (ACS). Four patients developed other tumors, three of whom died from this cause. It is not known whether these tumors could be related to the described mutation.

Impact of Morphology in the Genotype and Phenotype Correlation of Bilateral Macronodular Adrenocortical Disease (BMAD): A Series of Clinicopathologically Well-Characterized 35 Cases

Bilateral macronodular adrenocortical disease (BMAD) is characterized by the development of adrenal macronodules resulting in a pituitary-ACTH independent Cushing's syndrome. Although there are important similarities observed between the rare microscopic descriptions of this disease, the small series published are not representative of the molecular and genetic heterogenicity recently described in BMAD. We analyzed the pathological features in a series of BMAD and determined if there is correlation between these criteria and the characteristics of the patients. Two pathologists reviewed the slides of 35 patients who underwent surgery for suspicion of BMAD in our center between 1998 and 2021. An unsupervised multiple factor analysis based on microscopic characteristics divided the cases into 4 subtypes according to the architecture of the macronodules (containing or not round fibrous septa) and the proportion of the different cell types: clear, eosinophilic compact, and oncocytic cells. The correlation study with genetic revealed subtype 1 and subtype 2 are associated with the presence of ARMC5 and KDM1A pathogenic variants, respectively. By immunohistochemistry, all cell types expressed CYP11B1 and HSD3B1. HSD3B2 staining was predominantly expressed by clear cells whereas CYP17A1 staining was predominant on compact eosinophilic cells. This partial expression of steroidogenic enzymes may explain the low efficiency of cortisol production in BMAD. In subtype 1, trabeculae of eosinophilic cylindrical cells expressed DAB2 but not CYP11B2. In subtype 2, KDM1A expression was weaker in nodule cells than in normal adrenal cells; alpha inhibin expression was strong in compact cells. This first microscopic description of a series of 35 BMAD reveals the existence of 4 histopathological subtypes, 2 of which are strongly correlated with the presence of known germline genetic alterations. This classification emphasizes that BMAD has heterogeneous pathological characteristics that correlate with some genetic alterations identified in patients.

New advances in endocrine hypertension: from genes to biomarkers

Hypertension (HT) is a major cardiovascular risk factor that affects 10% to 40% of the general population in an age-dependent manner. Detection of secondary forms of HT is particularly important because it allows the targeted management of the underlying disease. Among hypertensive patients, the prevalence of endocrine HT reaches up to 10%. Adrenal diseases are the most frequent cause of endocrine HT and are associated with excess production of mineralocorticoids (mainly primary aldosteronism), glucocorticoids (Cushing syndrome), and catecholamines (pheochromocytoma). In addition, a few rare diseases directly affecting the action of mineralocorticoids and glucocorticoids in the kidney also lead to endocrine HT. Over the past years, genomic and genetic studies have allowed improving our knowledge on the molecular mechanisms of endocrine HT. Those discoveries have opened new opportunities to transfer knowledge to clinical practice for better diagnosis and specific treatment of affected subjects. In this review, we describe the physiology of adrenal hormone biosynthesis and action, the clinical and biochemical characteristics of different forms of endocrine HT, and their underlying genetic defects. We discuss the impact of these discoveries on diagnosis and management of patients, as well as new perspectives related to the use of new biomarkers for improved patient care.

Clinical, pathophysiologic, genetic and therapeutic progress in Primary Bilateral Macronodular Adrenal Hyperplasia

Patients with primary bilateral macronodular adrenal hyperplasia (PBMAH) usually present bilateral benign adrenocortical macronodules at imaging and variable levels of cortisol excess. PBMAH is a rare cause of primary overt Cushing's syndrome, but may represent up to one third of bilateral adrenal incidentalomas with evidence of cortisol excess. The increased steroidogenesis in PBMAH is often regulated by various G-protein coupled receptors aberrantly expressed in PBMAH tissues; some receptor ligands are ectopically produced in PBMAH tissues creating aberrant autocrine/paracrine regulation of steroidogenesis. The bilateral nature of PBMAH and familial aggregation, led to the identification of germline heterozygous inactivating mutations of the ARMC5 gene, in 20-25% of the apparent sporadic cases and more frequently in familial cases; ARMC5 mutations/pathogenic variants can be associated with meningiomas. More recently, combined germline mutations/pathogenic variants and somatic events inactivating the KDM1A gene were specifically identified in patients affected by GIP-dependent PBMAH. Functional studies demonstrated that inactivation of KDM1A leads to GIP-receptor (GIPR) overexpression and over or down-regulation of other GPCRs. Genetic analysis is now available for early detection of family members of index cases with PBMAH carrying identified germline pathogenic variants. Detailed biochemical, imaging, and co-morbidities assessment of the nature and severity of PBMAH is essential for its management. Treatment is reserved for patients with overt or mild cortisol/aldosterone or other steroid excesses taking in account co-morbidities. It previously relied on bilateral adrenalectomy; however recent studies tend to favor unilateral adrenalectomy, or less frequently, medical treatment with cortisol synthesis inhibitors or specific blockers of aberrant GPCR.

A Novel ARMC5 Germline Variant in Primary Macronodular Adrenal Hyperplasia Using Whole-Exome Sequencing

Background: Primary macronodular adrenocortical hyperplasia (PMAH) is a rare form of adrenal Cushing’s syndrome with incomplete penetrance which may be sporadic or autosomal dominant. The inactivation of the ARMC5 gene, a potential tumor suppressor gene, is one of the associated causes of PMAH. This study aimed to identify the variant responsible for Iranian familial PMAH. Methods: The proband, a 44-year-old woman, was directed to whole-exome sequencing (WES) of the blood sample to discover a germline variant. In addition, the identified causative variant was confirmed and segregated in other and available unaffected family members. Results: The novel germline heterozygous missense variant, c.2105C>A in the ARMC5 gene, was found, and the same germline variant as the proband was confirmed in two affected sisters. This variant was detected in the brother of the proband with an asymptomatic condition and this considered because of incomplete penetrance and age-dependent appearance. The function of the ARMC5 protein would be damaged by the identified variant, according to in silico and computer analyses that followed. Conclusion: The new germline ARMC5 variation (c.2105C>A, (p. Ala702Glu)) was interpreted as a likely pathogenic variant based on ACMG and Sherloc standards. PMAH may be diagnosed early using genetic testing that shows inherited autosomal dominant mutations in the ARMC5 gene.