Current Insights Into Adrenal Insufficiency in the Newborn and Young Infant

Insights in non-CAH pediatric primary adrenal insufficiency: a single-center experience from India

OBJECTIVES

Pediatric primary adrenal insufficiency (PAI) etiologies beyond congenital adrenal hyperplasia (CAH) show regional variations. Given limited data from India, this study aims to describe the etiological profile, phenotype, and genotype of pediatric PAI in an Indian cohort.

METHODS

We conducted a retrospective review of patients with PAI onset before 20 years of age from 1998 to 2023 at a single center. After excluding patients with inadequate data (n=20), CAH (n=218), and bilateral adrenalectomy (n=19), we analyzed demographic, clinical, biochemical, and genetic data of the remaining patients.

RESULTS

Among 54 patients (45 probands), the median age at presentation was 6 years (range 0.1-19). Common clinical features included hyperpigmentation (90.7 %), adrenal crisis (33.3 %), and seizures (29.6 %). Mineralocorticoid deficiency was present in two-third patients including one patient each with AAAS, MRAP, and NNT mutation. Adrenoleukodystrophy (ALD) was the most common cause (40 %), followed by ACTH resistance states (20 %), early steroidogenic defects (13.3 %), congenital adrenal hypoplasia (11.1 %), autoimmune causes (8.9 %), and tuberculosis (4.5 %). Genetics diagnosed 14/15 patients without phenotypic clues and confirmed diagnoses in 21 tested of 30 with phenotypic pointers (alacrimia in AAAS, hypoparathyroidism/candidiasis in autoimmune polyendocrine syndrome-1 and neurodeficit in ALD). Genetics differentiated CYP11A1 mutation from suspected ALD in two siblings with neurological deficits. We identified seven novel gene variants. We report the first case of NNT associated with 46,XY gonadal dysgenesis. Adrenal tuberculosis was a unique cause of pediatric PAI.

CONCLUSIONS

This study reveals diverse non-CAH pediatric PAI etiologies in India, emphasizing genetic testing's importance for precise diagnoses and suggests region-specific diagnostic algorithm.

Primary adrenal insufficiency in children excluding congenital adrenal hyperplasia: insights from 33-year single-center experience in Tunisia

BACKGROUND

Primary adrenal insufficiency (PAI) is a rare but potentially life-threatening condition. Congenital adrenal hyperplasia (CAH) is the most common cause of PAI in children. To date, numerous non-CAH causes have been identified through genetic analysis but they remain poorly characterized.

OBJECTIVE

We aimed to describe the clinical presentation, etiology, genetic analysis, and long-term outcome of non-CAH PAI in children.

METHODS

We retrospectively collected clinical and laboratory data from patients with non-CAH PAI who were followed up during a period of 33 years (1988-2020) at the pediatric department of a university hospital center in southern Tunisia.

RESULTS

We identified 52 patients with non-CAH PAI (35 boys and 17 girls). The mean age at diagnosis was 4.8 years (0.05-18.7 years). Hyperpigmentation was the most frequent symptom at diagnosis (92.3%), followed by asthenia (84.6%), weight loss (57.7%), recurrent vomiting (53.8%), and dehydration (42.3%). The most prominent biochemical findings were hyponatremia (60.4%), hypoglycemia (35.4%), and hyperkalemia (16.6%). A total of 21patients (40.4%) presented with adrenal crisis at disease onset. The most common causes of non-CAH PAI were inherited genetic conditions and included Allgrove syndrome (n=15), X-linked adrenoleukodystrophy (n=10), autoimmune polyglandular syndrome (APS) type 2 (n=2), familial glucocorticoid deficiency type 1 (n=1), MCM4 mutation responsible for DNA repair defect (n=1), SF1 deficiency (n=1), APS type 1 (n=1), and autoimmune PAI (n=3). The cause of PAI remained unknown in 34.6% of cases. During follow-up, 24 patients (46.2%) presented with statural growth delay, and eight patients (15.4%) developed obesity.

CONCLUSION

Allgrove syndrome was the most common etiology of non-CAH PAI in our study, followed by X-linked adrenoleukodystrophy. Today, advanced molecular analysis can be useful for diagnostic investigations, especially in patients with no specific diagnostic features.

The Causes and Diagnosis of Non-congenital Adrenal Hyperplasia Primary Adrenal Insufficiency in Children

Primary adrenal insufficiency (PAI) is a critical condition that requires prompt diagnosis and initiation of treatment. Diagnosis can be challenging due to various underlying causes, including defects in adrenal gland development, resistance to adrenocorticotropic hormone, autoimmune causes, and metabolic problems. A specific diagnosis is essential for developing a treatment plan and identifying other possible accompanying pathologies. Biochemical studies, genetic analyses, and imaging techniques are helpful in establishing a specific diagnosis. This evidence-based guideline includes the specific diagnoses that cause PAI and their clinical and genetic features. It also provides evidence-based steps to follow when making a diagnosis.

Genetics of Primary Adrenal Insufficiency Beyond CAH in Saudi Arabian Population

BACKGROUND

The use of exome sequencing (ES) has helped in detecting many variants and genes that cause primary adrenal insufficiency (PAI). The diagnosis of PAI is difficult and can be life-threatening if not treated urgently. Consanguinity can impact the detection of recessively inherited genes. Here, we report families with PAI in a consanguineous population of Saudi Arabia.

MATERIALS AND METHODS

A cohort of 47 PAI patients (41 males and six females) representing 30 families was recruited. The cohort excluded congenital adrenal hyperplasia (CAH) cases and had a known consanguinity of 70%. Using ES, molecular genetic causes of PAI were investigated.

RESULTS

In 30 unrelated families with PAI, pathogenic/likely pathogenic variants were detected in 27 families with a diagnostic yield of (90%). Clinically associated variants of uncertain significance (VUS) were identified in a further two PAI families (7%). Hemizygous variants in ABCD1 were the most common cause of PAI in this cohort (16 families) leading to adrenoleukodystrophy. A total of six novel variants were detected, of which four were predicted to be pathogenic (P) / likely pathogenic (LP) and two were VUS. Four pathogenic variants in ABCD1, NR0B1, and MC2R were detected in 10 families suggesting founder mutations.

CONCLUSION

In this cohort, ES detected a diagnostic molecular abnormality in 90% of patients with PAI phenotypes. X-linked inheritance is the most common cause of PAI and founder mutations likely contributed to a high diagnostic yield.

Impact of corticosteroid exposure on preterm labor in neonates eventually born at term

OBJECTIVE

To evaluate the impact of antenatal corticosteroid therapy (ACS) on birth outcomes in term infants exposed during pregnancy.

STUDY DESIGN

Exposed newborns were compared with non-exposed controls in a 1 to 2 design. Multivariate analysis was used to assess the effect of ACS exposure on neonatal outcomes.

RESULT

408 newborns were included (136 exposed to ACS, 272 non-exposed). Mean ± SD head circumference (HC) was 33.7 ± 1.4 vs 34.3 ± 1.6 cm, p = 0.001 in exposed vs controls; birth weight was 3.1 ± 0.4 vs 3.3 ± 0.4 kg, p = 0.0001; and birth height was 47.9 ± 2.1 vs. 49.1 ± 2.0 cm, p < 0.0001. Hypocalcemia (4.4 vs 0.7%, p = 0.019) and feeding difficulties (5.1 vs 1.5%, p = 0.047) were significantly more common in exposed newborns. Multivariate analysis for HC showed a significant independent association with ACS exposure (β = -0.5, p = 0.009).

CONCLUSION

Term newborns exposed to ACS have lower birth HC and higher risk of neonatal complications.

CLINICAL TRIAL REGISTRATION

NCT05640596.

Neglected Adrenal Hypoplasia Congenita in Two Siblings with Novel Genetic Mutations in NR0B1 Gene and Notable Clinical Course: A Case Report

BACKGROUND

Adrenal Hypoplasia Congenita (AHC) is a rare subtype of primary adrenal insufficiency (PAI) that can go undiagnosed easily. In this article, we report two brothers with hypogonadotropic hypogonadism and novel mutations in the NR0B1 gene who were misdiagnosed and mismanaged as having congenital adrenal hypoplasia (CAH) for several years.

CASE PRESENTATION

Herein, we describe two brothers with similar histories; first, they were diagnosed with CAH and treated for that; however, after several years, they showed symptoms of lack of testosterone despite receiving CAH treatment. Low levels of testosterone and LH were detected in both, and a genetic test of CAH was negative for the first brother. Thereafter, DAX- 1 deficiency was suspected, and their genetic tests (the NR0B1 gene) confirmed the diagnosis of DAX-1.

CONCLUSION

The diagnosis of CAH in case of low levels of 17- OHP, testosterone, and LH, as well as central hypogonadotropic hypogonadism, should be studied, and further investigations are mandatory to evaluate other subtypes of PAI, especially AHC.

Familial Glucocorticoid Deficiency: the changing landscape of an eponymous syndrome

Familial Glucocorticoid Deficiency encompasses a broad spectrum of monogenic recessive disorders that theoretically solely abrogate cortisol biosynthesis. In reality, delineating clear genotype-phenotype correlations in this disorder is made complicated by marked phenotypic heterogeneity even within kindreds harbouring identical variants. Phenotypes range from isolated glucocorticoid insufficiency to cortisol deficiency plus a variety of superimposed features including salt-wasting and hypoaldosteronism, primary hypothyroidism, hypogonadism and growth defects. Furthermore, mutation type, domain topology and perceived enzyme activity do not always predict disease severity. Given the high burden of disease and implications of a positive diagnosis, genetic testing is crucial in the management of patients warranting detailed delineation of genomic variants including viable functional studies.

Neonatal Endocrine Diseases

Endocrine diseases are rare and can present very subtly in the neonatal period. Most are diagnosed using newborn screening in the United States; however, some infants may present with false negatives or more subtle findings. Endocrine etiologies should be considered during the management of critically ill infants. This article will give an overview of endocrine emergencies encountered in the neonatal period, including disorders of glucose metabolism, thyroid disorders, adrenal disorders, and pituitary disorders.

An integrated single-cell analysis of human adrenal cortex development

The adrenal glands synthesize and release essential steroid hormones such as cortisol and aldosterone, but many aspects of human adrenal gland development are not well understood. Here, we combined single-cell and bulk RNA sequencing, spatial transcriptomics, IHC, and micro-focus computed tomography to investigate key aspects of adrenal development in the first 20 weeks of gestation. We demonstrate rapid adrenal growth and vascularization, with more cell division in the outer definitive zone (DZ). Steroidogenic pathways favored androgen synthesis in the central fetal zone, but DZ capacity to synthesize cortisol and aldosterone developed with time. Core transcriptional regulators were identified, with localized expression of HOPX (also known as Hop homeobox/homeobox-only protein) in the DZ. Potential ligand-receptor interactions between mesenchyme and adrenal cortex were seen (e.g., RSPO3/LGR4). Growth-promoting imprinted genes were enriched in the developing cortex (e.g., IGF2, PEG3). These findings reveal aspects of human adrenal development and have clinical implications for understanding primary adrenal insufficiency and related postnatal adrenal disorders, such as adrenal tumor development, steroid disorders, and neonatal stress.

Rare forms of genetic paediatric adrenal insufficiency: Excluding congenital adrenal hyperplasia

Adrenal insufficiency (AI) is a severe endocrine disorder characterized by insufficient glucocorticoid (GC) and/or mineralocorticoid (MC) secretion by the adrenal glands, due to impaired adrenal function (primary adrenal insufficiency, PAI) or to insufficient adrenal stimulation by pituitary ACTH (secondary adrenal insufficiency, SAI) or tertiary adrenal insufficiency due to hypothalamic dysfunction. In this review, we describe rare genetic causes of PAI with isolated GC or combined GC and MC deficiencies and we also describe rare syndromes of isolated MC deficiency. In children, the most frequent cause of PAI is congenital adrenal hyperplasia (CAH), a group of adrenal disorders related to steroidogenic enzyme deficiencies, which will not be included in this review. Less frequently, several rare diseases can cause PAI, either affecting exclusively the adrenal glands or with systemic involvement. The diagnosis of these diseases is often challenging, due to the heterogeneity of their clinical presentation and to their rarity. Therefore, the current review aims to provide an overview on these rare genetic forms of paediatric PAI, offering a review of genetic and clinical features and a summary of diagnostic and therapeutic approaches, promoting awareness among practitioners, and favoring early diagnosis and optimal clinical management in suspect cases.

Diagnostic approach in 46, XY DSD: an endocrine society of bengal (ESB) consensus statement

OBJECTIVES

46, XY difference/disorder of sex development (DSD) is a relatively uncommon group of heterogeneous disorders with varying degree of underandrogenization of male genitalia. Such patients should be approached systematically to reach an aetiological diagnosis. However, we lack, at present, a clinical practice guideline on diagnostic approach in 46, XY DSD from this part of the globe. Moreover, debate persists regarding the timing and cut-offs of different hormonal tests, performed in these cases. The consensus committee consisting of 34 highly experienced endocrinologists with interest and experience in managing DSD discussed and drafted a consensus statement on the diagnostic approach to 46, XY DSD focussing on relevant history, clinical examination, biochemical evaluation, imaging and genetic analysis.

CONTENT

The consensus was guided by systematic reviews of existing literature followed by discussion. An initial draft was prepared and distributed among the members. The members provided their scientific inputs, and all the relevant suggestions were incorporated. The final draft was approved by the committee members.

SUMMARY

The diagnostic approach in 46, XY DSD should be multidisciplinary although coordinated by an experienced endocrinologist. We recommend formal Karyotyping, even if Y chromosome material has been detected by other methods. Meticulous history taking and thorough head-to-toe examination should initially be performed with focus on external genitalia, including location of gonads. Decision regarding hormonal and other biochemical investigations should be made according to the age and interpreted according to age-appropriate norms Although LC-MS/MS is the preferred mode of steroid hormone measurements, immunoassays, which are widely available and less expensive, are acceptable alternatives. All patients with 46, XY DSD should undergo abdominopelvic ultrasonography by a trained radiologist. MRI of the abdomen and/or laparoscopy may be used to demonstrate the Mullerian structure and/or to localize the gonads. Genetic studies, which include copy number variation (CNV) or molecular testing of a candidate gene or next generation sequencing then should be ordered in a stepwise manner depending on the clinical, biochemical, hormonal, and radiological findings.

OUTLOOK

The members of the committee believe that patients with 46, XY DSD need to be approached systematically. The proposed diagnostic algorithm, provided in the consensus statement, is cost effective and when supplemented with appropriate genetic studies, may help to reach an aetiological diagnosis in majority of such cases.

Steroid Hormone Profiles and Molecular Diagnostic Tools in Pediatric Patients With non-CAH Primary Adrenal Insufficiency

CONTEXT

There is a significant challenge of attributing specific diagnoses to patients with primary adrenal insufficiency of unknown etiology other than congenital adrenal hyperplasia (non-CAH PAI). Specific diagnoses per se may guide personalized treatment or may illuminate pathophysiology.

OBJECTIVE

This work aimed to investigate the efficacy of steroid hormone profiles and high-throughput sequencing methods in establishing the etiology in non-CAH PAI of unknown origin.

METHODS

Pediatric patients with non-CAH PAI whose etiology could not be established by clinical and biochemical characteristics were enrolled. Genetic analysis was performed using targeted-gene panel sequencing (TPS) and whole-exome sequencing (WES). Plasma adrenal steroids were quantified by liquid chromatography-mass spectrometry and compared to that of controls. This study comprised 18 pediatric endocrinology clinics with 41 patients (17 girls, median age: 3 mo, range: 0-8 y) with non-CAH PAI of unknown etiology.

RESULTS

A genetic diagnosis was obtained in 29 (70.7%) patients by TPS. Further molecular diagnosis could not be achieved by WES. Compared to a healthy control group, patients showed lower steroid concentrations, most statistically significantly in cortisone, cortisol, and corticosterone (P < .0001, area under the receiver operating characteristic curve: .96, .88, and .87, respectively). Plasma cortisol of less than 4 ng/mL, cortisone of less than 11 ng/mL, and corticosterone of less than 0.11 ng/mL had a greater than 95% specificity to ensure the diagnosis of non-CAH PAI of unknown etiology.

CONCLUSION

Steroid hormone profiles are highly sensitive for the diagnosis of non-CAH PAI of unknown etiology, but they are unlikely to point to a specific molecular diagnosis. TPS is an optimal approach in the molecular diagnosis of these patients with high efficacy, whereas little additional benefit is expected from WES.

An Update on Genetics of Adrenal Gland and Associated Disorders

The intricacies of human adrenal development have been under scrutiny for decades. Each year marks the identification of new genes and new interactions between gene products that ultimately will act to produce the fully functioning adult gland. Due to the complexity of this process, genetic missteps may lead to a constellation of pathologies. Recent years have identified several novel genetic causes of adrenal dysgenesis and provided new insights into previously delineated processes. SF1, DAX1 (NR0B1), CDKN1C, SAMD9, GLI3, TPIT, MC2R, MRAP, NNT, TXNRD2, AAAS, and MCM4 are among the genes which have had significant contributions to our understanding of the development and function of both adrenals and gonads. Collection and elucidation of these genetic and clinical insights are valuable tools for clinicians who diagnose and manage cases of adrenal dysfunction.

Can Digenic, Tri-Allelic Inheritance of Variants in STAR and CYP11A1 Give Rise to Primary Adrenal Insufficiency? A Case Report

An eight-year old South Asian boy presenting with progressive hyperpigmentation was found to have primary adrenal insufficiency (PAI) in the form of isolated glucocorticoid deficiency. Follow up of this boy for nine years, until the age of 17 years showed normal pubertal onset and progression. Molecular evaluation, by targeted next generation sequencing of candidate genes linked to PAI revealed changes in two genes that are intricately linked in the early stages of steroid biosynthesis: compound heterozygous variants in STAR, c.465+1G>A and p.(E99K), plus a heterozygous rs6161 change in CYP11A1. No variants in other known causal genes were detected. The proband's mother was heterozygous for the c.465+1G>A STAR and rs6161 CYP11A1 variants, while the father was homozygous for the p.(E99K) alteration in STAR but wild-type for CYP11A1. Both parents had normal adrenal cortical function as revealed by short Synacthen tests. The STAR variant c.465+1G>A will lead to abnormal splicing of exon 4 in mRNA and the addition of the p.(E99K) variant, predicted damaging by SIFT and CADD, may be sufficient to cause PAI but this is by no means certain given that the unaffected father is homozygous for the latter change. The rs6161 CYP11A1 variant [c.940G>A, p.(E314K)] has recently been demonstrated to cause PAI in conjunction with a severe rare disruptive change on the other allele, however sequencing of the coding region of CYP11A1 revealed no further changes in this subject. We wondered whether the phenotype of isolated glucocorticoid deficiency had arisen in this child due to tri-allelic inheritance of a heterozygous CYP11A1 change along with the two STAR variants each of which contribute a partial loss-of-function burden that, when combined, is sufficient to cause PAI or if the loss-of-function c.465+1G>A combined with the presumed partial loss-of-function p.(E99K) in STAR could be causative.

Pediatric Adrenal Insufficiency: Challenges and Solutions

Adrenal insufficiency is an insidious diagnosis that can be initially misdiagnosed as other life-threatening endocrine conditions, as well as sepsis, metabolic disorders, or cardiovascular disease. In newborns, cortisol deficiency causes delayed bile acid synthesis and transport maturation, determining prolonged cholestatic jaundice. Subclinical adrenal insufficiency is a particular challenge for a pediatric endocrinologist, representing the preclinical stage of acute adrenal insufficiency. Although often included in the extensive work-up of an unwell child, a single cortisol value is usually difficult to interpret; therefore, in most cases, a dynamic test is required for diagnosis to assess the hypothalamic-pituitary-adrenal axis. Stimulation tests using corticotropin analogs are recommended as first-line for diagnosis. All patients with adrenal insufficiency need long-term glucocorticoid replacement therapy, and oral hydrocortisone is the first-choice replacement treatment in pediatric. However, children that experience low cortisol concentrations and symptoms of cortisol insufficiency can take advantage using a modified release hydrocortisone formulation. The acute adrenal crisis is a life-threatening condition in all ages, treatment is effective if administered promptly, and it must not be delayed for any reason.

The etiology and clinical features of non-CAH primary adrenal insufficiency in children

BACKGROUND

The most common cause of primary adrenal insufficiency (PAI) in children is congenital adrenal hyperplasia; however, other genetic causes occur. There is limited epidemiological and clinical information regarding non-CAH PAI.

METHODS

Data for patients diagnosed from January 2015 to December 2021 at a tertiary hospital in northern China were retrospectively analyzed. We excluded those with CAH, which is the most common pathogenic disease among PAI patients. Next-generation sequencing was used for genetic analysis.

RESULTS

This retrospective study included 16 children (14 males and 2 females) with PAI. A genetic diagnosis was obtained for 14/16 (87.5%) individuals. Pathogenic variants occurred in 6 genes, including ABCD1 (6/16, 37.5%), NR0B1 (4/16, 25.0%), NR5A1/steroidogenic factor-1 (2/16; 12.5%), AAAS (1/16, 6.25%), and NNT (1/16, 6.25%). No genetic cause of PAI diagnosis was found in 2 girls (2/16, 12.5%).

CONCLUSIONS

Causes of PAI in children are diverse and predominantly affect males. Most PAI in children is congenital, and ABCD1 gene defects account for the largest proportion of PAI cases. Whole-exome sequencing is a tool for diagnosis. However, diagnoses are unclear in some cases.

Society for Endocrinology UK Guidance on the initial evaluation of a suspected difference or disorder of sex development (Revised 2021)

It is paramount that any child or adolescent with a suspected difference or disorder of sex development (DSD) is assessed by an experienced clinician with adequate knowledge about the range of conditions associated with DSD and is discussed with the regional DSD service. In most cases, the paediatric endocrinologist within this service acts as the first point of contact but involvement of the regional multidisciplinary service will also ensure prompt access to specialist psychology and nursing care. The underlying pathophysiology of DSD and the process of delineating this should be discussed with the parents and affected young person with all diagnostic tests undertaken in a timely fashion. Finally, for rare conditions such as these, it is imperative that clinical experience is shared through national and international clinical and research collaborations.

Case Report: Neonatal Cholestasis as Early Manifestation of Primary Adrenal Insufficiency

Neonatal cholestasis (NC) may be due to multiple surgical and non-surgical causes, some of which are potentially fatal. The list of potential causes of NC is long, and the systematic search for each of them is challenging in infants, especially when overt signs of underlying disease are lacking. Endocrinological diseases as causes of NC are rare and sometimes misdiagnosed. We report the case of an infant with prolonged cholestatic jaundice due to adrenal insufficiency suspected because of a single episode of hypoglycemia occurring at birth in the absence of clinical signs of adrenal impairment. Clinical exome analysis identified a new homozygous variant in MC2R gene as a putative responsible for familial glucocorticoid deficiency (FGD). Adrenal insufficiency should always be considered in all cholestatic infants, even in the absence of specific symptoms, since early recognition and treatment is essential to prevent life-threatening events.

Diverse etiologies, diagnostic approach, and management of primary adrenal insufficiency in pediatric age

Primary adrenal insufficiency (PAI) in pediatric age is a rare, but potentially fatal condition caused by diverse etiologies including biochemical defects of steroid biosynthesis, developmental abnormalities of the adrenal gland, or reduced responsiveness to adrenocorticotropic hormone. Compared to adult PAI, pediatric PAI is more often the result of genetic (monogenic, syndromic disorders) than acquired conditions. During the past decade, rare monogenic disorders associated with PAI have helped unravel the underlying novel molecular genetic mechanism. The diagnosis of adrenal insufficiency in children and young infancy is often challenging, usually based on clinical suspicion and endocrine laboratory findings. Pediatric endocrinologists sometimes encounter therapeutic difficulty in finding the balance between undertreatment and overtreatment, determining how to optimize the dose over the patient's lifetime, and maximizing mimicry of normal cortisol secretion with glucocorticoid replacement therapy.

Non-Canonical Effects of ACTH: Insights Into Adrenal Insufficiency

Introduction

Adrenocorticotropic hormone (ACTH) is produced from proopiomelanocortin, which is predominantly synthetized in the corticotroph and melanotroph cells of the anterior and intermediate lobes of the pituitary gland and the arcuate nucleus of the hypothalamus. Although ACTH clearly has an effect on adrenal homeostasis and maintenance of steroid hormone production, it also has extra-adrenal effects that require further elucidation.

Methods

We comprehensively reviewed English language articles, regardless of whether they reported the presence or absence of adrenal and extra-adrenal ACTH effects.

Results

In the present review, we provide an overview on the current knowledge on adrenal and extra-adrenal effects of ACTH. In the section on adrenal ACTH effects, we focused on corticosteroid rhythmicity and effects on steroidogenesis, mineralocorticoids and adrenal growth. In the section on extra-adrenal effects, we have analyzed the effects of ACTH on the osteoarticular and reproductive systems, adipocytes, immune system, brain and skin. Finally, we focused on adrenal insufficiency.

Conclusions

The role of ACTH in maintaining the function of the hypothalamic-pituitary-adrenal axis is well known. Conversely, if we broaden our vision and analyze its role as a potential treatment strategy in other conditions, it will be evident in the literature that researchers seem to have abandoned this aspect in studies conducted several years ago. We believe it is worth re-evaluating the role of ACTH considering its noncanonical effects on the adrenal gland itself and on extra-adrenal organs and tissues; however, this would not have been possible without the recent advances in the pertinent technologies.

Genetic Analysis of Pediatric Primary Adrenal Insufficiency of Unknown Etiology: 25 Years' Experience in the UK

CONTEXT

Although primary adrenal insufficiency (PAI) in children and young people is often due to congenital adrenal hyperplasia (CAH) or autoimmunity, other genetic causes occur. The relative prevalence of these conditions is poorly understood.

OBJECTIVE

We investigated genetic causes of PAI in children and young people over a 25 year period.

DESIGN SETTING AND PARTICIPANTS

Unpublished and published data were reviewed for 155 young people in the United Kingdom who underwent genetic analysis for PAI of unknown etiology in three major research centers between 1993 and 2018. We pre-excluded those with CAH, autoimmune, or metabolic causes. We obtained additional data from NR0B1 (DAX-1) clinical testing centers.

INTERVENTION AND OUTCOME MEASUREMENTS

Genetic analysis involved a candidate gene approach (1993 onward) or next generation sequencing (NGS; targeted panels, exomes) (2013-2018).

RESULTS

A genetic diagnosis was reached in 103/155 (66.5%) individuals. In 5 children the adrenal insufficiency resolved and no genetic cause was found. Pathogenic variants occurred in 11 genes: MC2R (adrenocorticotropin receptor; 30/155, 19.4%), NR0B1 (DAX-1; 7.7%), CYP11A1 (7.7%), AAAS (7.1%), NNT (6.5%), MRAP (4.5%), TXNRD2 (4.5%), STAR (3.9%), SAMD9 (3.2%), CDKN1C (1.3%), and NR5A1/steroidogenic factor-1 (SF-1; 0.6%). Additionally, 51 boys had NR0B1 variants identified through clinical testing. Although age at presentation, treatment, ancestral background, and birthweight can provide diagnostic clues, genetic testing was often needed to define the cause.

CONCLUSIONS

PAI in children and young people often has a genetic basis. Establishing the specific etiology can influence management of this lifelong condition. NGS approaches improve the diagnostic yield when many potential candidate genes are involved.

Adrenal insufficiency

Adrenal insufficiency (AI) is a condition characterized by an absolute or relative deficiency of adrenal cortisol production. Primary AI (PAI) is rare and is caused by direct adrenal failure. Secondary AI (SAI) is more frequent and is caused by diseases affecting the pituitary, whereas in tertiary AI (TAI), the hypothalamus is affected. The most prevalent form is TAI owing to exogenous glucocorticoid use. Symptoms of AI are non-specific, often overlooked or misdiagnosed, and are related to the lack of cortisol, adrenal androgen precursors and aldosterone (especially in PAI). Diagnosis is based on measurement of the adrenal corticosteroid hormones, their regulatory peptide hormones and stimulation tests. The goal of therapy is to establish a hormone replacement regimen that closely mimics the physiological diurnal cortisol secretion pattern, tailored to the patient's daily needs. This Primer provides insights into the epidemiology, mechanisms and management of AI during pregnancy as well as challenges of long-term management. In addition, the importance of identifying life-threatening adrenal emergencies (acute AI and adrenal crisis) is highlighted and strategies for prevention, which include patient education, glucocorticoid emergency cards and injection kits, are described.