Meg Keil

A genome-wide scan identifies mutations in the gene encoding phosphodiesterase 11A4 ( PDE11A ) in individuals with adrenocortical hyperplasia

Phosphodiesterases (PDEs) regulate cyclic nucleotide levels. Increased cyclic AMP (cAMP) signaling has been associated with PRKAR1A or GNAS mutations and leads to adrenocortical tumors and Cushing syndrome. We investigated the genetic source of Cushing syndrome in individuals with adrenocortical hyperplasia that was not caused by known defects. We performed genome-wide SNP genotyping, including the adrenocortical tumor DNA. The region with the highest probability to harbor a susceptibility gene by loss of heterozygosity (LOH) and other analyses was 2q31–2q35. We identified mutations disrupting the expression of the PDE11A isoform-4 gene (PDE11A) in three kindreds. Tumor tissues showed 2q31–2q35 LOH, decreased protein expression and high cyclic nucleotide levels and cAMP-responsive element binding protein (CREB) phosphorylation. PDE11A codes for a dual-specificity PDE that is expressed in adrenal cortex and is partially inhibited by tadalafil and other PDE inhibitors; its germline inactivation is associated with adrenocortical hyperplasia, suggesting another means by which dysregulation of cAMP signaling causes endocrine tumors.

The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes.

Stratakis CA, Tichomirowa MA, Boikos S, Azevedo MF, Lodish M, Martari M, Verma S, Daly AF, Raygada M, Keil MF, Papademetriou J, Drori‐Herishanu L, Horvath A, Tsang KM, Nesterova M, Franklin S, Vanbellinghen J‐F, Bours V, Salvatori R, Beckers A. The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes.

Diagnostic Tests for Children Who Are Referred for the Investigation of Cushing Syndrome

OBJECTIVE. Endogenous Cushing syndrome in children is a rare disorder that is most frequently caused by pituitary or adrenocortical tumors. Diagnostic criteria have generally been derived from studies of adult patients despite significant differences in both the physiology of the hypothalamic-pituitary-adrenal axis and the epidemiology of Cushing syndrome in childhood. The purpose of this study was to identify the tests that most reliably and efficiently diagnose pituitary or adrenal tumors in a large cohort of pediatric patients with Cushing syndrome. METHODS. A retrospective review of clinical data of children who were referred to a tertiary care center for evaluation for Cushing syndrome during the years 1997 to 2005 was conducted. A total of 125 consecutive children were studied retrospectively; 105 were found to have Cushing syndrome, which was confirmed histologically; and 20 children who did not have Cushing syndrome or any other endocrinopathy served as the control group. The following tests were performed in all children: midnight and morning cortisol, corticotropin hormone, urinary free cortisol and 17-hydroxycorticosteroid levels, ovine corticotropin-releasing hormone stimulation test, and overnight high-dosage dexamethasone suppression test. Imaging of the pituitary and adrenal glands was also obtained. The main outcome measure was the sensitivity of these parameters for the diagnosis and differential diagnosis of Cushing syndrome at 100% specificity. RESULTS. A midnight cortisol value of ≥4.4 μg/dL confirmed the diagnosis of Cushing syndrome in almost all children, with a sensitivity of 99% and a specificity of 100%. Suppression of morning cortisol levels >20% in response to an overnight, high-dosage dexamethasone test excluded all patients with adrenal tumors and identified almost all patients with pituitary tumors (sensitivity: 97.5%; specificity: 100%). CONCLUSIONS. Our study suggests that among children who were referred for the evaluation of possible Cushing syndrome, a single cortisol value at midnight followed by overnight high-dosage dexamethasone test led to rapid and accurate confirmation and diagnostic differentiation, respectively, of hypercortisolemia caused by pituitary and adrenal tumors.

Snapin Mediates Incretin Action and Augments Glucose-Dependent Insulin Secretion

Impaired insulin secretion contributes to the pathogenesis of type 2 diabetes mellitus (T2DM). Treatment with the incretin hormone glucagon-like peptide-1 (GLP-1) potentiates insulin secretion and improves metabolic control in humans with T2DM. GLP-1 receptor-mediated signaling leading to insulin secretion occurs via cyclic AMP stimulated protein kinase A (PKA)- as well as guanine nucleotide exchange factor-mediated pathways. However, how these two pathways integrate and coordinate insulin secretion remains poorly understood. Here we show that these incretin-stimulated pathways converge at the level of snapin, and that PKA-dependent phosphorylation of snapin increases interaction among insulin secretory vesicle-associated proteins, thereby potentiating glucose-stimulated insulin secretion (GSIS). In diabetic islets with impaired GSIS, snapin phosphorylation is reduced, and expression of a snapin mutant, which mimics site-specific phosphorylation, restores GSIS. Thus, snapin is a critical node in GSIS regulation and provides a potential therapeutic target to improve β cell function in T2DM.

Blood Pressure in Pediatric Patients with Cushing Syndrome

CONTEXT Hypertension (HTN) has been reported in up to 60% of children with Cushing syndrome (CS), but its course, side effects, and potential differences among various causes of CS have not been adequately studied. OBJECTIVE The objective of the study was to measure blood pressure in pediatric patients with CS before and after transphenoidal surgery or adrenalectomy and identify side effects and rates of residual HTN. DESIGN Data from 86 children with corticotropinomas [Cushing disease (CD)] and 27 children with ACTH-independent CS (AICS) were analyzed. RESULTS Patients with CD and AICS had significant HTN before surgery; more patients with AICS had systolic HTN (SHTN) than with CD (74 vs. 44%, P = 0.0077), but the rate of diastolic HTN (DHTN) was similar. Both groups experienced significant decreases in SHTN immediately after transphenoidal surgery and adrenalectomy. One year postoperatively, both SHTN and DHTN were lower than the preoperative values in all patients, but as many as 16 and 4% of the patients with CD and 21 and 5% of the patients with AICS still had SHTN and DHTN, respectively. Higher blood pressure preoperatively correlated with cortisol levels. Two patients suffered serious side effects: one with multiple infarcts and another with hypertensive encephalopathy. CONCLUSIONS Children with CS are at risk for residual HTN despite a significant improvement after surgical cure. HTN appears to correlate with the degree of hypercortisolemia. Serious HTN-related side effects, although rare, may occur during the perioperative period.

Operative management of Cushing Syndrome secondary to micronodular adrenal hyperplasia

BACKGROUND We reviewed our experience with micronodular adrenal hyperplasia (MAH), its pigmented variant primary pigmented nodular adrenocortical disease (PPNAD), and the association with Carneys complex (CNC) to better characterize these disorders. METHODS This retrospective study analyzes clinical data and operative reports of 34 patients identified with MAH and/or PPNAD who underwent resection between 1969 and 2006 at the Clinical Research Center, an inpatient research hospital at the National Institutes of Health. Symptoms and anthropometric and biochemical data were used to evaluate effect of resection. RESULTS Fifteen patients (44%) presented as adults and 19 (56%) as children. Twenty-five patients (74%) presented with noncyclic Cushing syndrome and 9 patients (26%) presented with cyclic Cushing syndrome. Thirty-one patients underwent bilateral resection; this was curative biochemically in 30 patients. Fourteen operations were performed laparoscopically (41%), and 20 were performed as open resections (59%). There was 1 postoperative complication in the laparoscopic group (7%) and 6 complications in the open group (30%; P = .20). Follow-up was available for 25 patients (74%). Statistically significant improvements in anthropometrics were observed for both adults and children. The most frequent manifestation of CNC requiring additional operation was cardiac myxoma, which was associated strongly with an atypical (cyclic) presentation of Cushing syndrome (P = .009). CONCLUSION Cushing syndrome due to MAH and PPNAD may be cured by bilateral adrenal resection. All patients should be screened for manifestations of CNC at the time of adrenal diagnosis with particular attention to cardiac disease.

Pseudotumor Cerebri after Surgical Remission of Cushing’s Disease

CONTEXT Pseudotumor cerebri has only been described after successful surgery for Cushings disease (CD) in case reports. We sought to establish the incidence and timing of its occurrence, identify predisposing factors, characterize the clinical presentations and their severity, and examine the effects of treatment in patients who underwent surgery for CD. SETTING This study was conducted at two tertiary care centers: The University of Virginia and the National Institutes of Health. PATIENTS We conducted a retrospective review of 941 surgeries for CD (723 adults, 218 children) to identify patients who developed pseudotumor cerebri after surgery for CD and examine the associated clinical features. RESULTS Seven children (four males, three females; 3%), but no adults, developed pseudotumor cerebri postoperatively. All underwent resection of an ACTH-secreting adenoma, and postoperative serum cortisol reached a nadir of less than 2 microg/dl. After surgery, all were placed on tapering hydrocortisone replacement therapy. Within 3-52 wk, all seven patients experienced symptoms of pseudotumor cerebri and had ophthalmological examination demonstrating papilledema. One patient had diplopia from a unilateral VIth nerve palsy. Six patients were still on steroid replacement at onset of symptoms. In three patients, a lumbar puncture demonstrated elevated opening pressure. Four patients were treated successfully with a lumbar puncture, steroids, and/or Diamox. Three patients did not receive treatment, and their symptoms resolved over several months. There was no correlation between the degree of hypercortisolism (24-h urinary free cortisol) before surgery and the likelihood of developing pseudotumor cerebri after surgery (P < 0.23). CONCLUSIONS This series demonstrates a 3% occurrence of pseudotumor cerebri in children after successful surgery for CD, but the absence of the syndrome in adults. Pseudotumor cerebri manifests itself within 1 yr of surgery, often while patients are still undergoing replacement steroid therapy. A patient exhibiting signs of intracranial hypertension after surgery for CD should undergo an evaluation for pseudotumor cerebri. Recognition of the symptoms and treatment should correct and/or prevent ophthalmological sequelae.

Ectopic Adrenocorticotropic Hormone and Corticotropin-Releasing Hormone Co-Secreting Tumors in Children and Adolescents Causing Cushing Syndrome: A Diagnostic Dilemma and How to Solve It

CONTEXT Ectopic ACTH/CRH syndrome is a rare cause of Cushing syndrome (CS), especially in children. The localization, work-up, and management of ACTH/CRH-secreting tumors are discussed. SETTING A retrospective study was conducted of patients under 21 years of age evaluated at the National Institutes of Health (NIH) for CS and diagnosed with ectopic ACTH/CRH-secreting tumors during the period 2009-2014. PATIENTS Seven patients with ectopic ACTH/CRH CS are included in this study with a median age 13.6 years (range 1-21), and 3 are female. MEASUREMENTS Clinical, biochemical, radiological features, treatment, and histological findings are described. RESULTS Seven patients were found to have ACTH/CRH-secreting tumors, all with neuroendocrine features. The site of the primary lesion varied: pancreas (3), thymus (2), liver (1), right lower pulmonary lobe (1). PATIENTS underwent biochemical evaluation for CS, including diurnal serum cortisol and ACTH levels, urinary free cortisol levels (UFC), and CRH stimulation tests. All patients underwent radiological investigations including MRI, CT, and PET scan; imaging with octreotide and 68 gallium DOTATATE scans were performed in individual cases. Five patients underwent inferior petrosal sinus sampling; 4 patients had sampling for ACTH and CRH levels from additional sites. Three patients underwent trans-sphenoidal surgery (TSS), and 3 patients required bilateral adrenalectomy. Three patients (43%) died due to metastatic disease, demonstrating the high mortality rate. One of the unique findings in these seven patients is that in each case, their neuroendocrine tumors were ultimately proven to be co-secreting ACTH and CRH. This explains the enigmatic presentation, in which 3 patients initially thought to have Cushings disease (CD) with corresponding pituitary hyperplasia underwent TSS prior to the correct localization of the causative tumor. CONCLUSIONS Ectopic ACTH/CRH co-secreting tumors are extremely rare in children and adolescents. The diagnosis of this condition is frequently missed and is sometimes confused with CD due to the effect of CRH on the pituitary.

Adrenal function in Smith-Lemli-Opitz Syndrome

Smith–Lemli–Opitz syndrome (SLOS) is a multiple malformation syndrome due to mutations of the 7‐dehydrocholesterol reductase gene (DHCR7), which leads to a deficiency of cholesterol synthesis and an accumulation of 7‐dehydrocholesterol. The SLOS clinical spectrum ranges from multiple major malformations to a mild phenotype with minor anomalies and intellectual disability. Several children with SLOS and adrenal insufficiency have been described. We performed ovine corticotropin (oCRH) testing in 35 SLOS patients and 16 age‐ and gender‐matched controls. We reviewed prior adrenocorticotropin (ACTH) stimulation tests of our SLOS patients (19 of 35 available) and reviewed results of ACTH stimulation tests from 10 additional SLOS patients. Results from oCRH testing showed that patients with SLOS had significantly higher ACTH baseline values than healthy controls (24.8 ± 15.3 pg/ml vs. 17.8 ± 7.5 pg/ml, P = 0.034). However, no statistically significant differences were noted for peak ACTH values (74.4 ± 35.0 pg/ml vs. 64.0 ± 24.9 pg/ml, P = 0.303) and for baseline (14.2 ± 7.8 mcg/dl vs. 14.2 ± 6.3 mcg/dl, P = 0.992) and peak cortisol values (28.2 ± 7.9 mcg/dl vs. 24.8 ± 8.1 mcg/dl, P = 0.156). The area‐under‐the‐curve (AUC) was not significantly different in SLOS patients compared to controls for both ACTH (250.1 ± 118.7 pg/ml vs. 195.3 ± 96.6 pg/ml, P = 0.121) as well as cortisol secretion (83.1 ± 26.1 mcg/dl vs. 77.8 ± 25.9 mcg/dl, P = 0.499). ACTH stimulation test results were normal in 28 of 29 tests. The individual with the abnormal test results had subsequent normal oCRH tests. The slightly increased baseline ACTH level seen during oCRH testing may be due to compensated adrenocortical insufficiency. However, we were able to show that our patients with SLOS had an adequate glucocorticoid response, and thus, in mild to moderate cases of SLOS stress steroid coverage may not be warranted. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.

Differences in Adiposity in Cushing Syndrome Caused by PRKAR1A Mutations: Clues for the Role of Cyclic AMP Signaling in Obesity and Diagnostic Implications

CONTEXT The cAMP signaling pathway is implicated in bilateral adrenocortical hyperplasias. Bilateral adrenocortical hyperplasia is often associated with ACTH-independent Cushing syndrome (CS) and may be caused by mutations in genes such as PRKAR1A, which is responsible for primary pigmented nodular adrenocortical disease (PPNAD). PRKAR1A regulates cAMP-dependent protein kinase (PKA), an essential enzyme in the regulation of adiposity. Although CS is invariably associated with obesity, its different forms, including those associated with PKA defects, have not been compared. OBJECTIVE The purpose of this study was to characterize the phenotypic and molecular differences in periadrenal adipose tissue (PAT) between patients with CS with and without PRKAR1A mutations. DESIGN AND SETTING Samples from adrenalectomies of 51 patients were studied: patients with CS with (n = 13) and without (n = 32) PRKAR1A mutations and a comparison group with aldosterone-producing adenomas (APAs) (n = 6). In addition, clinical data from a larger group of patients with Cushing disease (n = 89) and hyperaldosteronism (n = 26) were used for comparison. METHODS Body mass index (BMI), abdominal computed tomography scans, and cortisol data were collected preoperatively. PAT was assayed for PKA activity, cAMP levels, and PKA subunit expression. RESULTS BMI was lower in adult patients with CS with PRKAR1A mutations. cAMP and active PKA levels in PAT were elevated in patients with CS with PRKAR1A mutations. CONCLUSIONS Increased PKA signaling in PAT was associated with lower BMI in CS. Differences in fat distribution may contribute to phenotypic differences between patients with CS with and without PRKAR1A mutations. The observed differences are in agreement with the known roles of cAMP signaling in regulating adiposity, but this is the first time that germline defects of PKA are linked to variable obesity phenotypes in humans.