Characterization of the zebrafish as a model of ATP-sensitive potassium channel hyperinsulinism

INTRODUCTION

Congenital hyperinsulinism (HI) is the leading cause of persistent hypoglycemia in infants. Current models to study the most common and severe form of HI resulting from inactivating mutations in the ATP-sensitive potassium channel (KATP) are limited to primary islets from patients and the Sur1 -/- mouse model. Zebrafish exhibit potential as a novel KATPHI model since they express canonical insulin secretion pathway genes and those with identified causative HI mutations. Moreover, zebrafish larvae transparency provides a unique opportunity for in vivo visualization of pancreatic islets.

RESEARCH DESIGN AND METHODS

We evaluated zebrafish as a model for KATPHI using a genetically encoded Ca2+ sensor (ins:gCaMP6s) expressed under control of the insulin promoter in beta cells of an abcc8 -/- zebrafish line.

RESULTS

We observed significantly higher islet cytosolic Ca2+ in vivo in abcc8 -/- compared with abcc8 +/+ zebrafish larvae. Additionally, abcc8 -/- larval zebrafish had significantly lower whole body glucose and higher whole body insulin levels compared with abcc8 +/+ controls. However, adult abcc8 -/- zebrafish do not show differences in plasma glucose, plasma insulin, or glucose tolerance when compared with abcc8 +/+ zebrafish.

CONCLUSIONS

Our results identify that zebrafish larvae, but not adult fish, are a demonstrable novel model for advancement of HI research.

Visual Perception in Children with a History of Hypoglycemia due to Hyperinsulinism

Objectives

Hyperinsulinism refers to improper insulin secretion in the presence of low plasma glucose, causing severe and persistent hypoglycemia in infants and children. The brain's occipital lobe, which includes the visual and plays an essential role in visual perception is specifically sensitive to hypoglycemia-induced damage. The present study aims to investigate the visual perception in children suffering from hyperinsulinism and to compare it with the control group.

Materials & Methods

This cross-sectional control study, conducted in 2020 in Isfahan, Iran, involved 20 children aged 4-13 years with hyperinsulinism and 20 healthy children of the same age and gender for comparison. In both groups, the measuring instrument was the Test of Visual Perceptual Skills (non-motor) Third Edition.

Results

The mean visual perceptual quotient in the case and control groups was 80.50±26.74 and 116.50±7.56 (p-value<0.001), respectively. The results overall indicated that children suffering from hyperinsulinism were weaker than healthy children in all areas of visual perception.

Conclusion

Based on the obtained results, it is recommended that children suffering from hyperinsulinism be screened regarding visual perceptual disorders since this screening may be helpful in initiating different rehabilitation programs among these patients.

Drug-induced hyperinsulinemic hypoglycemia: An update on pathophysiology and treatment

The initial step for the differential diagnosis of hypoglycemia is to determine whether it is hyperinsulinemic or non hyperinsulinemic. Existing literature discusses drug-related hypoglycemia, but it misses a focus on drug-induced hyperinsulinemic hypoglycemia (DHH). Here we reviewed the association existing between drugs and hyperinsulinemic hypoglycemia. We primarily selected on the main electronic databases (MEDLINE, EMBASE, Web of Science, and SCOPUS) the reviews on drug-induced hypoglycemia. Among the drugs listed in the reviews, we selected the ones linked to an increase in insulin secretion. For the drugs missing a clear association with insulin secretion, we investigated the putative mechanism underlying hypoglycemia referring to the original papers. Our review provides a list of the most common agents associated with hyperinsulinemic hypoglycemia (HH), in order to facilitate both the recognition and the prevention of DHH. We also collected data about the responsiveness of DHH to diazoxide or octreotide.

Non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS)/Nesidioblastosis as the underlying cause of recurrent hypoglycemia in a diabetic adult

Non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS), without previous bariatric surgery, is a rare form of hypoglycemia in adult patients and is associated with nesidioblastosis. Adult-onset nesidioblastosis in diabetic patients is rare and histologically identical to "non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS)". Nesidioblastosis is rare in adults and clinically and biochemically mimics Insulinoma. In the literature, there have only been four cases of adult nesidioblastosis that followed diabetes mellitus. We report a case of nesidioblastosis in a 36-year-old diabetic female presenting with dizziness, sweating, and palpitations for three years. Selective non-invasive techniques failed to detect a tumor. Based on the pursuit of an insulinoma, a distal pancreatectomy specimen was received at our laboratory, and a diagnosis of nesidioblastosis was made. She is currently on follow-up with a favorable outcome. The definitive diagnosis of nesidioblastosis is made on a histological basis. The preferred form of treatment is pancreatic surgical resection. Nesidioblastosis should be taken into consideration in cases where diabetes transforms into hyperinsulinemic hypoglycemia.

Supernumerary chromosome 6 marker associated with paternal uniparental isodisomy of chromosome 6 in a patient with a syndromic disorder of insulin secretion

The association of both uniparental disomy and small supernumerary marker chromosomes is rare. Clinical impact depends on the presence of imprinted genes and/or the unmasking of a recessive mutation of the chromosome involved in the uniparental disomy and the euchromatic content of the sSMC. Here, we report on the second case of a patient harbouring a de novo supernumerary marker chromosome 6 causing partial trisomy 6p12.3p11.1 associated with a paternal uniparental isodisomy of chromosome 6. Our patient presented with intrauterine growth retardation, macroglossia, initial developmental delay and transient neonatal diabetes mellitus followed by a congenital hyperinsulinism. Diabetes and intrauterine growth retardation can be linked to the paternal isodisomy of the imprinted locus on chromosome 6q24 whereas developmental delay is probably due to the small supernumerary marker chromosome. However, the clinical impact of partial trisomy 6p is difficult to address due to a limited number of patients. The careful clinical examination and the molecular characterization of additional patients with trisomy 6p are needed to further predict the phenotype for genetic counselling. Finally, uniparental disomy should be considered when a sSMC involving a chromosome containing imprinted regions is detected, especially in the prenatal setting.

Expanding the p.(Arg85Trp) Variant-Specific Phenotype of HNF4A: Features of Glycogen Storage Disease, Liver Cirrhosis, Impaired Mitochondrial Function, and Glomerular Changes

Introduction

The p.(Arg85Trp) variant-specific phenotype of hepatocyte nuclear factor 4 alpha shows a complex clinical picture affecting three different organ systems and their corresponding metabolisms. Little is known about the molecular mechanisms involved and their relationship with the diverse symptoms seen in the context of this specific variant. Here, we present data of a new patient that expand the clinical phenotype, suggesting possible disease mechanisms.

Case Presentation

Clinical data were extracted from the patient's charts. The liver, kidney, and muscle were analyzed with routine histology and electron microscopy. Mitochondrial function was assessed by respirometric analyses and enzymatic activity assays. Structure and sequence analyses of this specific variant were investigated by in silico analyses. Our patient showed the known features of the variant-specific phenotype, including macrosomia, congenital hyperinsulinism, transient hepatomegaly, and renal Fanconi syndrome. In addition to that, she showed liver cirrhosis, chronic kidney failure, and altered mitochondrial morphology and function. The clinical and biochemical phenotype had features of a new type of glycogen storage disease.

Discussion

This case expands the p.(Arg85Trp) variant-specific phenotype. Possible pathomechanistic explanations for the documented multiorgan involvement and changes of symptoms and signs during development of this ultra-rare but instructive disorder are discussed.

Endocrine disorders associated with obesity

Several endocrine disorders, including diabetes, insulinoma, Cushing syndrome, hypothyroidism, polycystic ovarian syndrome, and growth hormone deficiency, are associated with obesity. The mechanisms underlying the development of obesity vary according to the abnormalities of endocrine function. The primary actions of insulin, glucocorticoids (GCs), thyroid hormone, and growth hormone are associated with energy metabolism in the liver, muscle, adipose tissue, and other tissues. This chapter describes the pathogenesis of obesity and metabolic dysfunction associated with excess insulin or GCs and the deficiency of thyroid hormone or growth hormone.

Diazoxide-unresponsive Hyperinsulinemic Hypoglycaemia in a Preterm Infant with Heterozygous Insulin Receptor Gene Mutation

Homozygous or compound heterozygous mutations in insulin receptor gene (INSR) lead to marked insulin resistance and hyperglycaemia in Donohue syndrome and Rabson-Mendenhall syndrome, conditions which are associated with significant morbidity early in life. On the other hand, heterozygous INSR gene mutations result in milder phenotype known as type A insulin resistance syndrome. While presentation in adults with this condition is well reported, phenotypes in infant are less well-characterized. We herein report an infant presenting with hyperinsulinemic hypoglycaemia who did not respond to diazoxide therapy. She was subsequently found to carry heterozygous INSR gene mutation. Our patient was a female infant born at 29 weeks of gestation who developed recurrent hypoglycaemia in early infancy. Workup showed hyperinsulinism and she was started on first-line therapy with diazoxide and high-calorie feeds. However, continuous blood glucose monitoring showed post-prandial hyperglycaemia followed by rapid fall to hypogylcaemia. Whole exome sequencing was performed to investigate for diazoxide-unresponsive hyperinsulinism, which revealed a likely pathogenic mutation in the INSR gene c.1246C>T p. (R416X). This nonsense mutation was inherited from the father. With the molecular diagnosis, diazoxide was stopped and she followed a diet with low glycaemic-index food. Subsequent monitoring showed stable glucose profile. Our case highlights the importance to consider type A insulin resistance syndrome when no mutation could be identified in the ABCC8/KCNJ11 genes in diazoxide-unresponsive hyperinsulinism. With autosomal dominant inheritance, cascade screening should be performed in family members to identify those harbouring the mutation as they are at risk of early onset diabetes.

Recommendations for the diagnosis and treatment of hypoglycaemia after bariatric surgery

Postprandial hyperinsulinaemic hypoglycaemia is a common complication of bariatric surgery. Although in general its evolution is mild and self-limited, it can lead to neuroglycopaenia and compromise the patient's safety and quality of life. The aim of this document is to offer some recommendations to facilitate the clinical care of these complex patients, reviewing the aetiopathogenesis, its diagnosis and treatment that, sequentially, will include dietary and pharmacological measures and surgery in refractory cases. In the absence of high-quality studies, the diagnostic and therapeutic approach proposed is based on the consensus of experts of the Grupo de Obesidad de la Sociedad Española de Endocrinología y Nutrición [Obesity Group of the Spanish Society of Endocrinology and Nutrition], GOSEEN. Those undergoing bariatric surgery should be informed of the possibility of developing this complication.

Mosaic GLUD1 Mutations Associated with Hyperinsulinism Hyperammonemia Syndrome

INTRODUCTION

The hyperinsulinemia-hyperammonemia syndrome (HIHA) is the second most common cause of congenital hyperinsulinism and is caused by activating heterozygous missense mutations in GLUD1. In the majority of HIHA cases, the GLUD1 mutation is found to be de novo. We have identified 3 patients in whom clinical evaluation was suggestive of HIHA but with negative mutation analysis in peripheral blood DNA for GLUD1 as well as other known HI genes.

METHODS

We performed next-generation sequencing (NGS) on peripheral blood DNA from two children with clinical features of HIHA in order to look for mosaic mutations in GLUD1. Pancreas tissue was also available in one of these cases for NGS. In addition, NGS was performed on peripheral blood DNA from a woman with a history of HI in infancy whose child had HIHA due to a presumed de novo GLUD1 mutation.

RESULTS

Mosaic GLUD1 mutations were identified in these 3 cases at percent mosaicism ranging from 2.7% to 10.4% in peripheral blood. In one case with pancreas tissue available, the mosaic GLUD1 mutation was present at 17.9% and 28.9% in different sections of the pancreas. Two unique GLUD1 mutations were identified in these cases, both of which have been previously reported (c.1493c>t/p.Ser445Leu and c.820c>t/p.Arg221Cys).

CONCLUSION

The results suggest that low-level mosaic mutations in known HI genes may be the underlying molecular mechanism in some children with HI who have negative genetic testing in peripheral blood DNA.

Concomitant dysregulation of androgen secretion and dysfunction of adipose tissue induced insulin resistance

Hyperandrogenism and hyperinsulinemia have resulted from dysfunction of the theca cell of the ovary and adipose tissue and each one potentiates the other in patients with androgen excess disorders e.g., polycystic ovary disease and idiopathic hirsutism. Possible external and/or internal triggers can produce such cellular dysfunction. There is evidence that sodium valproate acts as a trigger of cellular dysfunction and produces both hyperinsulinemia and hyperandrogenism. Therefore, the elimination of these triggers can help the patients to recover from hyperinsulinemia, insulin resistance and hyperandrogenism.

Congenital hyperinsulinism: localization of a focal lesion with (18)F-FDOPA positron emission tomography

Hyperinsulinemic hypoglycemia of infancy, also known as congenital hyperinsulinism, is a group of disorders characterized by dysregulated insulin release. Neonates with severe, persistent hyperinsulinemic hypoglycemia who are unresponsive to medical therapy require pancreatectomy to prevent brain damage from hypoglycemia. To date, multiple genetic mutations and syndromes and several unique histopathological entities have been identified in children with hyperinsulinism. Histopathology is characterized as diffuse, focal or atypical. Surgical resection of a focal lesion results in a cure in up to 97% of these children. Imaging with 6-fluoro-(¹⁸F)-L-3,4-dihydroxyphenylalanine (¹⁸F-FDOPA) positron emission tomography (PET) is the test of choice for identifying and localizing a focal lesion and has proved to be an invaluable guide for surgical resection. Genetic evaluation is essential for determining who will benefit from PET imaging. This article provides an approach to determine who should be imaged, how to set up a protocol and how to interpret the imaging findings. The diagnosis and management of this disorder require a multidisciplinary approach to prevent brain damage from hypoglycemia.

Advances in Understanding the Mechanism of Transitional Neonatal Hypoglycemia and Implications for Management

Our lack of basic knowledge about the basic mechanisms of transitional hypoglycemia and other forms of hypoglycemia in newborns underlies the ongoing controversies over standards for managing these conditions. To address this deficiency, the authors evaluated regulation of insulin secretion in fetal, newborn, and adult rats. The results demonstrate that transitional hypoglycemia in normal neonates and persistent hypoglycemia in high-risk infants both reflect altered beta-cell insulin regulation. These findings provide a new foundation for improving detection and management and preventing hypoglycemic brain injury in normal neonates and, especially, in infants with persistent hypoglycemia and genetic forms of congenital hyperinsulinism.

Sirolimus in infants with congenital hyperinsulinism (CHI) - a single-centre experience

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycaemia in neonates and infants. Medical treatment includes the use of high concentrations of glucose and combinations of diazoxide, octreotide and glucagon. We report our experience of using sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, in the treatment of CHI in seven newborns who are poorly responding to standard medical therapy. Majority (87%) of infants achieved euglycaemia using a combination of oral feeding and the addition of sirolimus to standard medical treatment. One infant who failed to achieve euglycaemia even after surgery managed successfully with sirolimus. Diagnosis was confirmed by genetics evaluation; in three infants, novel mutations were detected. Outcome and long-term follow-up of all cases are described.Conclusion: Sirolimus can be considered in treatment of CHI refractory to standard medical treatment or in cases unresponsive to surgical treatment. What is Known: • Congenital hyperinsulinism (CHI) or persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI) associated with mutations such as the ABBC8 or KCNJ gene known to cause hypoglycaemia refractory to standard medical treatment such as diazoxide and octreotide and may need subtotal pancreatectomy (STP). • Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, was recently reported to be useful for refractory CHI cases with variable efficacy. What is New: • Our case series describes efficacy and safety of sirolimus in seven genetically proven refractory CHI cases with mainly neonatal presentation. All patients' follow-ups are described. • Out of seven infants, six infants responded well to sirolimus, and among these one infant who failed to respond to surgery (STP) also successfully managed with sirolimus. • It highlights the right patient selection and right dose to successfully manage these cases without much adverse effects.

[Insulin autoimmune syndrome : A rare, but important differential diagnosis of hypoglycemia]

Eine 69-jährige Patientin mit rezidivierenden schweren Hypoglykämien wurde zur weiteren Diagnostik der Medizinischen Hochschule Hannover zugewiesen. Zuvor hatte die Patientin nach einem Stenting, das aufgrund einer peripheren arteriellen Verschlusskrankheit (pAVK) erforderlich war, mit einer Clopidogreleinnahme begonnen. Das Vorliegen eines Insulinoms und eines paraneoplastischen Syndroms wurde ausgeschlossen. Trotz niedrig normaler Blutzuckerkonzentrationen fanden sich erhöhte Insulin- und Insulinautoantikörperkonzentrationen. Diagnostiziert wurde ein Insulinautoimmunsyndrom, a.e. (am ehesten) ausgelöst durch vorausgegangene Clopidogreleinnahme. Eine Behandlung mithilfe der Immunadsorption wurde initiiert; diese erzielte eine signifikante Reduktion der hypoglykämischen Ereignisse und ein anhaltendes Therapieansprechen über 3 Monate.

Clinical Predictors of Transient versus Persistent Neonatal Hyperinsulinism

INTRODUCTION

Hyperinsulinism (HI), the most common neonatal cause of persistent hypoglycemia, can be associated with prolonged hospitalizations and risk for long-term neurological sequelae. Rapid identification of transient versus persistent forms of HI is crucial to optimize management.

OBJECTIVES

The aims of the study were to assess the ability of clinical and biochemical features at presentation to predict transient versus persistent HI, and to evaluate differences in hospital outcomes.

METHODS

This study is a retrospective review of 79 infants with HI admitted to the Hospital for Sick Children, Toronto, from 2012 to 2017. Patients were classified into 3 groups: transient and the 2 persistent forms, diazoxide responsive and diazoxide unresponsive (DU).

RESULTS

Infants with birth weight >90th percentile had an 8-fold increased risk of having a persistent form of HI (OR 8.8, 95% CI 2.5-30) and a 21-fold increased risk of having a DU form of HI (OR 21.1, 95% CI 4.9-91.8). The majority of children with transient HI and a birth weight >90th percentile were born to mothers with gestational diabetes. There were no other useful clinical or biochemical presenting features that differentiated the groups. There were significant differences in outcome measures, with the DU children more likely to require gastrostomy tube insertion and have an extended length of hospital admission.

CONCLUSION

A higher birth weight in the absence of maternal gestational diabetes is highly associated with a persistent form of HI. Given the marked difference in clinical outcomes between groups, expedited genetic testing should be considered in infants with this presentation to inform clinical management.

The Term Newborn: Hypoglycemia

This review provides an update on neonatal hypoglycemia in the term infant, including discussion of glucose metabolism, definitions of hypoglycemia, identification of infants commonly at risk, and the screening, treatment, and potential neurologic outcomes of postnatal hypoglycemia. Neonatal hypoglycemia is a common metabolic condition that continues to plague clinicians because there is no clear relationship between low glucose concentrations or their duration that determines adverse neurologic outcomes. However, severely low, prolonged, recurrent low glucose concentrations in infants who also have marked symptoms such as seizures, flaccid hypotonia with apnea, and coma clearly are associated with permanent brain damage. Early identification of at-risk infants, early and continued breastfeeding augmented with oral dextrose gel, monitoring prefeed glucose concentrations, treating symptomatic infants who have very low and recurrent low glucose concentrations, and identifying and aggressively managing infants with persistent hyperinsulinemia and metabolic defects may help prevent neuronal injury.

Expanding the spectrum of endocrinopathies identified in Schaaf-Yang syndrome - A case report and review of the literature

Schaaf-Yang syndrome is a genetic disorder caused by mutations in the paternal allele of the MAGEL2 gene. Developmental delay, feeding difficulties, joint contractures and a high prevalence of autism spectrum disorders are characteristic of the syndrome. Endocrine abnormalities include mostly various pituitary hormonal deficiencies, presenting as hypoglycemia in 48% of reported cases. Persistent hyperinsulinism was only described in two siblings and responded to diazoxide treatment. We describe a unique case of an infant with Schaaf-Yang syndrome that presented with persistent hyperinsulinism unresponsive to diazoxide. Furthermore, we conducted a literature review of the endocrine abnormalities described in MAGEL2 related disorders. The case presented expands the clinical phenotype of Schaaf-Yang syndrome and emphasizes the importance of endocrine follow-up in these patients. Further investigation into the role of MAGEL2 in the regulation of pancreatic beta-cell insulin secretion, will improve our understanding of the abnormalities in glucose regulation in this syndrome.

Conjugated hyperbilirubinemia among infants with hyperinsulinemic hypoglycemia

From clinical practice, we noted that a subset of neonates with hyperinsulinism develop conjugated hyperbilirubinemia. A relationship between these two conditions has not been previously described. We aimed to assess the incidence of cholestasis in a cohort of neonates with hyperinsulinism and describe their clinical characteristics. In a retrospective cohort of 63 neonates with hyperinsulinism, 48% developed cholestasis (conjugated bilirubin > 17 μmol/L) with a median maximum conjugated bilirubin of 81 [21 to 191] μmol/L. A history of fetal distress (RR 2.3 [1.24-4.45], p < 0.01) and prematurity (RR 2.0 [1.23-3.26], p <0.01) was associated with the development of cholestasis, but not parental nutrition or other pharmacological treatments. An underlying etiology for the cholestasis was only found in 1 patient, and in all cases the cholestasis spontaneously improved.Conclusions: A significant percentage of infants with hyperinsulinism develop idiopathic, spontaneously resolving, conjugated hyperbilirubinemia. The association with a history of fetal distress potentially suggests that intrauterine factors leading to hyperinsulinism may also predispose towards conjugated hyperbilirubinemia. While the presence of neonatal cholestatic jaundice warrants timely investigations to exclude important underling etiologies, if validated, these findings may support a less invasive diagnostic workup of conjugated hyperbilirubinemia in infants with co-existent hyperinsulinism. What is Known: • Hyperinsulinism and conjugated hyperbilirubinemia are two common presentations in neonates. • A clinical association between the two conditions has not been described. What is New: • A significant proportion of infants with hyperinsulinism develop idiopathic, spontaneously resolving conjugated hyperbilirubinemia. • Increased risk for cholestasis in this patient population is associated with fetal distress and prematurity but not parental nutrition.

Neonatal hyperinsulinism in transient and classical forms of tyrosinemia

BACKGROUND

The spectrum of disorders associated with hyperinsulinemic hypoglycemia (HHI) has vastly increased over the past 20 years with identification of molecular, metabolic and cellular pathways involved in the regulation of insulin secretion and its actions. Hereditary tyrosinemia (HT1) is a rare metabolic disorder associated with accumulation of toxic metabolites of the tyrosine pathway due to a genetically mediated enzyme defect of fumarylacetoacetate hydrolase. Transient tyrosinemia of the newborn (TTN) is a benign condition with a maturational defect of the enzymes associated with tyrosine metabolism without any genetic abnormalities.

RESULTS

We describe two rare cases of HHI, one in a patient with HT1 and for the first time, in a patient with TTN. Each of our patients presented in the neonatal period with persistent hypoglycemia that on biochemical evaluation was consistent with HHI. Each patient received diazoxide therapy for 3.5 months and 17 months of life, respectively and HHI resolved thereafter.

CONCLUSION

Despite the fact that HHI has been described in HT1 for several decades, no specific mechanism has been delineated. Although we considered the common embryonal origin of the liver and pancreas with the hepatotoxic effect in HT1 also impacting the latter, this was not a possible explanation for TTN. The commonality between our two patients is the accumulation of certain amino acids which are known to be insulinotropic. We therefore hypothesize that the excess of amino acids such as leucine, lysine, valine and isoleucine in our patients resulted in HHI, which was transient. Both patients responded to diazoxide. This novel presentation in TTN and the reassuring response in both HT1 and TTN to diazoxide will be useful to inform physicians about managing HHI in these patients. Further studies are required to delineate the mechanism of HHI in these infants.

18-F-L 3,4-Dihydroxyphenylalanine PET/Computed Tomography in the Management of Congenital Hyperinsulinism

Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycemia in neonates and infants. Several genetic mutations have been identified and are associated with 2 distinct histopathologic forms of disease: diffuse and focal. Targeted clinical evaluation to distinguish medically treatable disease from disease requiring surgical management can prevent life-threatening complications. Detection and localization of a surgically curable focal lesion using PET imaging with 18-F-L 3,4-dihydroxyphenylalanine ([18F]-FDOPA) has become standard of care. This article provides guidelines for the selection of patients who can benefit from [18F]-FDOPA-PET/computed tomography and protocols and tips used to diagnose a focal lesion of HI.

Hyperinsulinemic hypoglycemia in children and adolescents: Recent advances in understanding of pathophysiology and management

Hyperinsulinemic hypoglycemia (HH) is characterized by unregulated insulin release, leading to persistently low blood glucose concentrations with lack of alternative fuels, which increases the risk of neurological damage in these patients. It is the most common cause of persistent and recurrent hypoglycemia in the neonatal period. HH may be primary, Congenital HH (CHH), when it is associated with variants in a number of genes implicated in pancreatic development and function. Alterations in fifteen genes have been recognized to date, being some of the most recently identified mutations in genes HK1, PGM1, PMM2, CACNA1D, FOXA2 and EIF2S3. Alternatively, HH can be secondary when associated with syndromes, intra-uterine growth restriction, maternal diabetes, birth asphyxia, following gastrointestinal surgery, amongst other causes. CHH can be histologically characterized into three groups: diffuse, focal or atypical. Diffuse and focal forms can be determined by scanning using fluorine-18 dihydroxyphenylalanine-positron emission tomography. Newer and improved isotopes are currently in development to provide increased diagnostic accuracy in identifying lesions and performing successful surgical resection with the ultimate aim of curing the condition. Rapid diagnostics and innovative methods of management, including a wider range of treatment options, have resulted in a reduction in co-morbidities associated with HH with improved quality of life and long-term outcomes. Potential future developments in the management of this condition as well as pathways to transition of the care of these highly vulnerable children into adulthood will also be discussed.

Intrauterine Growth Restriction and Hypertrophic Cardiomyopathy as Prenatal Ultrasound Findings in a Case of Leprechaunism

Donohue syndrome (leprechaunism; OMIM *246200) is a rare and often lethal autosomal recessive disease caused by mutations in the INSR gene. We report the case of a 29-year-old pregnant woman, primigravida, who was referred at 33 weeks of gestation for severe intrauterine growth restriction (IUGR). Ultrasound examination found severe IUGR associated with an obstructive hypertrophic cardiomyopathy (HCM), confirmed postnatally. The newborn's blood glucose level fluctuated from fasting hypoglycemia to postprandial hyperglycemia. The infant was found to be homozygous for a novel missense pathogenic variant, c.632C>T (p.T211l), in exon 2 of the INSR gene, predicted to result in an abnormal insulin receptor. To our knowledge, this is the first report of leprechaunism being revealed by IUGR and HCM during the prenatal period. Clinicians should keep in mind that the association of these prenatal signs could indicate leprechaunism and specific early neonatal management could be proposed, in particular with recombinant human insulin-like growth factor-I.

Hyperinsulinemic Hypoglycemia in a Patient with Costello Syndrome: An Etiology to Consider in Hypoglycemia

Several endocrine disorders have been defined in patients with Costello syndrome (CS). In this report, we describe a patient with CS accompanied by a clinical picture of hyperinsulinemic hypoglycemia responsive to diazoxide treatment. A 41-day-old female patient with a birth weight of 3,600 g was referred for atypical facial features and swallowing dysfunction. She had a weight of 4,000 g (-0.8 SDS), a length of 50 cm (-2.4 SDS), and a head circumference of 38 cm (0.2 SDS). The clinical findings were suggestive of a genetic syndrome, mainly a RASopathy or Beckwith-Wiedemann syndrome. Whole exome sequencing revealed a de novo heterozygous missense variant in the HRAS (NM_001130442) gene in exon 2: c.35G>C; p.(Gly12Ala), establishing the molecular diagnosis of CS. The patient developed symptomatic hypoglycemia (jitteriness and sweating) at the age of 13 months. The patient's serum glucose was 38 mg/dL with simultaneous serum insulin and C-peptide levels, 2.8 μIU/mL and 1.8 ng/mL, respectively. Hyperinsulinism was suspected, and an exaggerated glucose response was detected in a glucagon test. Blood glucose monitoring indicated episodes of fasting hypoglycemia and postprandial hyperglycemia. Diazoxide of 10 mg/kg/day was initiated in 3 doses for hyperinsulinemic hypoglycemia, which resolved without new episodes of postprandial hyperglycemia. The patient deceased at the age of 17 months due to cardiorespiratory failure in the course of severe pneumonia complicated with pulmonary hypertension and hypertrophic cardiomyopathy. Several genetic syndromes including CS are associated with endocrinologic manifestations including abnormal glucose homeostasis. Although the frequency and underlying mechanisms leading to hyperinsulinemic hypoglycemia are yet unknown, hypoglycemia in CS responds well to diazoxide.

Neonatal hyperinsulinemic hypoglycemia: case report of kabuki syndrome due to a novel KMT2D splicing-site mutation

Background

Persistent neonatal hypoglycemia, owing to the possibility of severe neurodevelopmental consequences, is a leading cause of neonatal care admission. Hyperinsulinemic hypoglycemia is often resistant to dextrose infusion and needs rapid diagnosis and treatment. Several congenital conditions, from single gene defects to genetic syndromes should be considered in the diagnostic approach. Kabuki syndrome type 1 (MIM# 147920) and Kabuki syndrome type 2 (MIM# 300867), can be associated with neonatal hyperinsulinemic hypoglycemia.

Patient presentation

We report a female Italian (Sicilian) child, born preterm at 35 weeks gestation, with persistent hypoglycemia. Peculiar facial dysmorphisms, neonatal hypotonia, and cerebellar vermis hypoplasia raised suspicion of Kabuki syndrome. Hyperinsulinemic hypoglycemia was confirmed with glucagon test and whole-exome sequencing (WES) found a novel heterozygous splicing-site mutation (c.674-1G > A) in KMT2D gene. Hyperinsulinemic hypoglycemia was successfully treated with diazoxide. At 3 months corrected age for prematurity, a mild global neurodevelopmental delay, postnatal weight and occipitofrontal circumference growth failure were reported.

Conclusions

Kabuki syndrome should be considered when facing neonatal persistent hypoglycemia. Diazoxide may help to improve hyperinsulinemic hypoglycemia. A multidisciplinary and individualized follow-up should be carried out for early diagnosis and treatment of severe pathological associated conditions.

Refinement of the critical genomic region for congenital hyperinsulinism in the Chromosome 9p deletion syndrome

Background: Large contiguous gene deletions at the distal end of the short arm of chromosome 9 result in the complex multi-organ condition chromosome 9p deletion syndrome.  A range of clinical features can result from these deletions with the most common being facial dysmorphisms and neurological impairment. Congenital hyperinsulinism is a rarely reported feature of the syndrome with the genetic mechanism for the dysregulated insulin secretion being unknown.  Methods: We studied the clinical and genetic characteristics of 12 individuals with chromosome 9p deletions who had a history of neonatal hypoglycaemia. Using off-target reads generated from targeted next-generation sequencing of the genes known to cause hyperinsulinaemic hypoglycaemia (n=9), or microarray analysis (n=3), we mapped the minimal shared deleted region on chromosome 9 in this cohort. Targeted sequencing was performed in three patients to search for a recessive mutation unmasked by the deletion. Results: In 10/12 patients with hypoglycaemia, hyperinsulinism was confirmed biochemically. A range of extra-pancreatic features were also reported in these patients consistent with the diagnosis of the Chromosome 9p deletion syndrome. The minimal deleted region was mapped to 7.2 Mb, encompassing 38 protein-coding genes. In silico analysis of these genes highlighted SMARCA2 and RFX3 as potential candidates for the hypoglycaemia. Targeted sequencing performed on three of the patients did not identify a second disease-causing variant within the minimal deleted region. Conclusions: This study identifies 9p deletions as an important cause of hyperinsulinaemic hypoglycaemia and increases the number of cases reported with 9p deletions and hypoglycaemia to 15 making this a more common feature of the syndrome than previously appreciated.  Whilst the precise genetic mechanism of the dysregulated insulin secretion could not be determined in these patients, mapping the deletion breakpoints highlighted potential candidate genes for hypoglycaemia within the deleted region.

Genetics of Neonatal Hypoglycaemia

Hypoglycaemia is the most common metabolic health complication in newborns. Persistent and severe hypoglycaemia in a neonate is correlated with morbidity and could represent an early clinical manifestation of an endocrine or metabolic, genetically determined disorder. Besides this, the most common reason for neonatal hypoglycaemia is the inmature liver storage of glucose seen in preterms or children born intrauterine growth retarded. The genetic determination of hypoglycaemia is gene- and allele- heterogeneous, and thus complex to diagnose. Nevertheless its contribution to brain damage and intellectual disability in children provides a strong rationale for comprehensive and rapid testing. Hypoglycaemia may contribute directly to the phenotype of various genetic syndromes but because of their rarity, it has been not always included in differential diagnosis and its frequency has been underestimated. In clinical practice but also with the growing attention to improved neonatal helathcare and to neonatal genetic screening programmes, the detailed classification of genotype to phenotype is of great importance. This review provides a catalogue of syndromic forms of neonatal hypoglycaemia.

Menopausal hyperinsulinism and hypertension - new approach

Aim: to test effects of estradiol (E2) 1 mg and drospirenone (DRSP) 2 mg in treatment of normal weight menopausal women with typical menopausal symptoms, hyperinsulinism, and grade I hypertension.Material and methods: The participants were 133 menopausal women, mean age 51.82 ± 3.25 years, body mass index (BMI) 24.9 ± 2.6 kg/m², waist/hip 0.80 ± 0.05, amenorrhoeic period 2.12 ± 2.10 years. All patients were treated with E2 1 mg and DRSP 2 mg during 12 months period. Blood samples were taken at 8 am before and during 12 months of therapy for: glycemia, lipids, hormonal analysis, follicle-stimulating hormone (FSH), luteinizing hormone (LH), E2, testosterone (T), prolactin (PRL), dehydroepiandrosterone sulfate (DHEAS), and sex hormone-binding globulin (SHBG). Oral glucose tolerance test (OGTT) was performed with 75 g glucose in order to assess insulin secretion. All had grade I hypertension 24 h blood pressure monitoring was performed before and after 12 months of therapy.Results: E2/DRSP significantly decreased total cholesterol, low-density lipoprotein (LDL), apolipoprotein B (ApoB), and increased high-density lipoprotein cholesterol (HDL) and apolipoprotein A (ApoA). Insulin area under the curve (AUC) significantly decreased (6586.1 ± 4194.2 vs. 5315.3 ± 2895.0, p < .05) and homeostatic model assessment (HOMA) (3.53 ± 2.18 vs. 3.0 ± 1.8, p < .05). FSH, LH decreased, E2 increased significantly. Of 24 h day blood pressure decreased significantly.Conclusions: E2/DRSP represents suitable therapy for hyperinsulinemic, grade I hypertensive menopausal women with typical symptoms and normal weight.

Coexistence of paternally-inherited ABCC8 mutation and mosaic paternal uniparental disomy 11p hyperinsulinism

Background

Beckwith–Wiedemann syndrome (BWS) is an overgrowth syndrome with variable clinical phenotype and complex molecular aetiology. It is mainly caused by dysregulation of the chromosome 11p15 imprinted region, which results in overgrowth in multiple tissues, often in a mosaic manner.

Case presentation

A large-for-gestational-age infant without any other somatic features of BWS presented with medically refractory hyperinsulinism (HI) requiring 80% pancreatectomy. Next generation sequencing with congenital HI sequencing panel identified a pathogenic ABCC8:c.1792C > T (p.Arg598Ter) variant of paternal origin, suggestive of focal HI. However, pancreatic histology revealed atypical findings of coalescing nests and trabeculae of adenomatosis scattered with islets with isolated enlarged, hyperchromatic nuclei scattered throughout the pancreas. Methylation analysis, SNP-based chromosomal microarray and short tandem repeat markers analysis revealed mosaic segmental paternal uniparental disomy (UPD) 11p15.5-p15.1 in the pancreatic tissue, but not the peripheral blood, suggestive of BWS/BW-spectrum HI.

Conclusions

This case highlights the importance of integrating the clinical presentation and subsequent clinical course, together with radiological, genetic and histological findings in the definitive diagnosis of this rare yet clinically important entity. In addition, this is the first report that demonstrated the level of paternal inherited c.1792 T pathogenic variant in the pancreatic tissue being directly correlated to the mosaic level of pUPD.

Meeting Report: Updates in Diagnosis and Management of Hyperinsulinism and Neonatal Hypoglycemia: Highlights from the Fourth International Hyperinsulinism Symposium

Hypoglycemia remains a significant cause of morbidity in infants and children. Up to 50% of children with hypoglycemic disorders suffer from neurodevelopmental deficits, as a consequence of delays in the diagnosis and inadequate treatment. Recent advances in the field have resulted in new therapies and improved outcomes. To review these advances and have a dialogue regarding controversies in the field, the Fourth International Hyperinsulinism Symposium, sponsored by the Children's Hospital of Philadelphia was held in Philadelphia, Pennsylvania on September 5-6, 2019. The symposium faculty, leaders in the field of hyperinsulinism and hypoglycemia, presented 25 plenary lectures on all aspects of these disorders. Additionally, a mini-symposium on neonatal hypoglycemia closed out the conference. Objectives of the symposium were to: 1. Describe the clinical manifestations, genetics and natural history of congenital hyperinsulinism 2. Review recent advances in the medical and surgical management of hyperinsulinism 3. Discuss current controversies and management options of neonatal hypoglycemia.

The role of 18F-DOPA PET/CT in the diagnosis of the congenital focal form of hyperinsulinism in children

BACKGROUND

Congenital hyperinsulinism (CHI) is a neuroendocrine disease with focal or diffuse abnormalities in pancreas. While drug-resistant diffuse forms require near-total pancreatectomy or prolonged pharmacotherapy, focal CHI may be treated by targeted surgical resection. We evaluated the usefulness of ¹⁸F-DOPA PET/CT to identify the focal pancreatic form.

SUBJECTS AND METHODS

Nineteen children (11 boys, 8 girls, aged 2-54 months) with clinical signs of neonatal CHI and positive genetic examinations were enrolled in the study. After i.v. administration of ¹⁸F-DOPA, early PET and late PET/CT acquisition covering one-bed length over thoraco-abdominal region were performed. Both acquisitions were done in dynamic mode to allow exclusion of frames with motion artefacts. Standardized uptake values were adjusted to bodyweight (SUV_bw). The finding was considered as focal when the ratio of SUV_bw^max between the suspicious region and the rest of pancreas was greater than 1.2.

RESULTS

Focal forms were recorded in 10/19 children and 4 of them underwent surgical resection with complete recovery. Focal uptake was significantly higher than the uptake in the normal pancreatic tissue (p=0.0059). Focal and diffuse forms of CHI did not differ significantly in normal pancreatic tissue uptake. We found no advantage in the measurement of SUV_bw^mean ratio compared to SUV_bw^max ratio (p=0.50).

CONCLUSION

¹⁸F-DOPA PET/CT is a useful tool for the localization of focal CHI and planning of surgical treatment.

Nationwide survey of endogenous hyperinsulinemic hypoglycemia in Japan (2017-2018): Congenital hyperinsulinism, insulinoma, non-insulinoma pancreatogenous hypoglycemia syndrome and insulin autoimmune syndrome (Hirata's disease)

AIMS/INTRODUCTION

We aimed to investigate the nationwide incidence, treatment details and outcomes of patients with endogenous hyperinsulinemic hypoglycemia (EHH), including those with transient/persistent congenital hyperinsulinism (CHI), insulinoma, non-insulinoma pancreatogenous hypoglycemia syndrome and insulin autoimmune syndrome (Hirata's disease) in Japan.

MATERIALS AND METHODS

A nationwide, questionnaire-based survey was carried out to determine the number of patients with EHH who were treated for hypoglycemia or hypoglycemia-related complications in 2017-2018. The questionnaires were sent to all hospitals in Japan with >300 beds, and with pediatric and/or adult clinics likely managing EHH patients. The secondary questionnaires were sent to obtain the patients' date of birth, sex, age at onset, treatment details and post-treatment outcomes.

RESULTS

A total of 447 patients with CHI (197 transient CHI, 225 persistent CHI and 25, unknown histology), 205 with insulinoma (118 benign, 18 malignant and 69 unknown subtype), 111 with non-insulinoma pancreatogenous hypoglycemia syndrome (33 post-gastric surgery HH, 57 postprandial HH, 10 nesidioblastosis and 11 unknown subtype) and 22 with insulin autoimmune syndrome were identified. Novel findings included: (i) marked improvement in the prognosis of persistent CHI over the past 10 years; (ii) male dominance in the incidence of transient CHI; (iii) non-insulinoma pancreatogenous hypoglycemia syndrome emerging as the second most common form of EHH in adults; (iv) frequent association of diabetes mellitus with insulin autoimmune syndrome; and (v) frequent post-treatment residual hypoglycemia and impaired quality of life.

CONCLUSIONS

The first nationwide, all age group survey of EHH showed the current status of each type of EHH disorder and the unmet needs of the patients.

Congenital hyperinsulinism: characterization of patients treated in a pediatric university hospital in Colombia

Background

Congenital hyperinsulinism is a disease of the glucose metabolism, relevant in pediatric endocrinology because of the elevated production of insulin according to blood glucose level, which leads to persistent severe hypoglycemia. This condition can produce important neurological sequelae in the patient due to the irreversible damage that occurs in the neuron caused by the exposure to hypoglycemia for short periods of time. Congenital hyperinsulinism diagnosis is not simple and it requires a high index of suspicion. The treatment should be established sequentially, in several steps, noticing the response to each possible medication used. If the pharmacological management fails, surgical procedures are required occasionally.

Case series report

Seven cases of congenital hyperinsulinism diagnosed in the last seven years at the Instituto Roosevelt in Bogotá, Colombia are presented. In this country, the radiotracer used internationally during positron emission tomography/computed tomography (PET/CT) is not available. However, was possible to use an alternative radiotracer in one of the cases, which led to an adequate diagnosis and a successful surgical treatment.

Conclusions

Congenital hyperinsulinism is a complex clinical condition, which requires proper diagnosis and treatment, with the aim of avoiding any neurological damage caused by persistent hypoglycemia. PET/CT can be used with an appropriate radiotracer for a timely diagnosis and to provide the best available therapeutic option.

Diagnostic Genetic Testing for Monogenic Diabetes and Congenital Hyperinsulinemia

Monogenic diabetes and hyperinsulinism are genetically heterogeneous disorders. The determination of the genetic etiology defines the diagnostic subtype, predicts prognosis, and importantly can guide clinical management. This chapter focuses on the processes and methodologies utilized in the diagnostic testing for monogenic diabetes and congenital hyperinsulinism (i.e., Sanger sequencing and targeted next-generation sequencing).

Hyperinsulinemic hypoglycemia caused by nesidioblastosis associated with non-surgical weight loss

INTRODUCCIÓN

La nesidioblastosis es una enfermedad poco frecuente en los adultos caracterizada por hiperplasia de los islotes pancreáticos, produciendo hipoglucemia por incremento de la producción de insulina. Su patogenia es poco conocida. Clínicamente se ha descrito un cuadro de hipoglucemia con valores elevados de insulina y de péptido C sin ninguna lesión tumoral pancreática detectable. El diagnóstico final es histopatológico.

CASO CLÍNICO

Mujer de 36 años que cursa con episodios recurrentes de hipoglucemia sintomática de predominio posprandial, asociada a elevación de los valores sanguíneos de insulina y péptido C. Los estudios de imágenes (tomografía computarizada trifásica, resonancia magnética, ecoendoscopia y octreoscan) no mostraron lesiones compatibles con insulinoma. Se le realizó estimulación intraarterial con calcio, que mostró un incremento de la insulinemia en más de un segmento pancreático posestimulación. La paciente fue sometida a pancreatectomía corporocaudal, cuya evaluación histopatológica informó de nesidioblastosis.

CONCLUSIONES

La nesidioblastosis representa menos del 5% de los casos de hipoglucemia hiperinsulinémica en los adultos, por lo que debe considerarse como diagnóstico -diferencial en estos pacientes; su diagnóstico es difícil y requiere confirmación histopatológica.

BACKGROUND

Nesidioblastosis is a rare disease in adults caused by pancreatic islet hyperplasia, producing hypoglycemia due to an increase in insulin production. The pathogenesis is poorly understood, however a clinical picture characterized by hypoglycemia with high levels of insulin and C-peptide without any detectable pancreatic lesion has been described, its final diagnosis is histological.

CASE REPORT

We report a case of a 36-year-old female patient who presents with recurrent episodes of hypoglycemia symptomatic predominantly postprandial, associated with insulin and C-peptide elevation. Images were made (triphasic computed tomography, magnetic resonance imaging, echoendoscopy and octreoscan), being negative for insulinoma. Subsequent tests included calcium stimulation of the pancreas, revealing marked insulin release in more than one pancreatic segment. The patient was subjected to distal pancreatectomy confirming in the histological study the diagnosis of nesidioblastosis.

CONCLUSIONS

Nesidioblastosis accounts for less than 5% of the cases of cases of hyperinsulinemic hypoglycemia in adult patients, should be considered as a differential diagnosis in patients with persistent hypoglycemia, the diagnosis is difficult and usually requires histological confirmation.

Insulin autoimmune syndrome induced by exogenous insulin injection: a four-case series

BACKGROUND

Insulin autoimmune syndrome (IAS) is a rare cause of hypoglycemia and is characterized by the presence of insulin autoantibodies. Patients with IAS usually complain of hypoglycemia without any previous insulin received. Glucocorticoids and immunosuppressants are used to treat IAS.

CASE PRESENTATION

We report four patients with diabetes who were diagnosed with non-classical IAS and describe the treatment of these patients. Moreover, the differential diagnosis with hyperinsulinism is discussed.

CONCLUSION

High levels of insulin autoantibodies, as well as hyperinsulinemic hypoglycemia, are found in patients with diabetes mellitus and prior exogenous insulin exposure. This situation that we classified as non-classical IAS should be attached importance to.

Rate of Serious Adverse Events Associated with Diazoxide Treatment of Patients with Hyperinsulinism

INTRODUCTION

Diazoxide is the first line and only Federal Drug Agency approved pharmacological agent for the treatment of hyperinsulinism. Its use has increased over the years to include patients with various genetic forms of hyperinsulinism, perinatal stress hyperinsulinism and infants of diabetic mothers with more babies than ever being exposed to this therapy.

METHODS

We performed a retrospective analysis of 194 patients with hyperinsulinism in our clinic and looked for those who had experienced serious adverse events (SAE) including pulmonary hypertension and neutropenia. We compared the rates of SAE in the different types of hyperinsulinism.

RESULTS

Out of 194 patients with hyperinsulinism, 165 (85.1%) were treated with diazoxide. There were 17 SAEs in 16 patients including 8 cases of pulmonary hypertension and 8 of neutropenia. These data show that overall the frequency of SAE associated with diazoxide use is 9.7%, but that those with perinatal stress hyperinsulinism have a much higher rate than those with genetic forms of hyperinsulinism (16.7 vs. 3.6%; p = 0.01). We also found diazoxide is associated with pulmonary hypertension (4.8% of patients treated). Although more patients with perinatal stress hyperinsulinism (7.6%) were affected than genetic hyperinsulinism (1.2%), the difference was not significant (p = 0.088).

CONCLUSION

The rate of SAEs associated with (not necessarily caused by) diazoxide has been demonstrated. The rate of SAE in newborns with perinatal stress hyperinsulinism is significantly higher than that of otherwise healthy babies with genetic forms of hyperinsulinism, suggesting that caution should be used when prescribing diazoxide to this population. This information should help balance the risk benefit of treatment and provide guidance on screening for these complications in the population of treated patients.

Refinement of the critical genomic region for hypoglycaemia in the Chromosome 9p deletion syndrome

Background: Large contiguous gene deletions at the distal end of the short arm of chromosome 9 result in the complex multi-organ condition chromosome 9p deletion syndrome.  A range of clinical features can result from these deletions with the most common being facial dysmorphisms and neurological impairment. Congenital hyperinsulinism is a rarely reported feature of the syndrome with the genetic mechanism for the dysregulated insulin secretion being unknown.  Methods: We studied the clinical and genetic characteristics of 12 individuals with chromosome 9p deletions who had a history of neonatal hypoglycaemia. Using off-target reads generated from targeted next-generation sequencing of the genes known to cause hyperinsulinaemic hypoglycaemia (n=9), or microarray analysis (n=3), we mapped the minimal shared deleted region on chromosome 9 in this cohort. Targeted sequencing was performed in three patients to search for a recessive mutation unmasked by the deletion. Results: In 10/12 patients with hypoglycaemia, hyperinsulinism was confirmed biochemically. A range of extra-pancreatic features were also reported in these patients consistent with the diagnosis of the Chromosome 9p deletion syndrome. The minimal deleted region was mapped to 7.2 Mb, encompassing 38 protein-coding genes. In silico analysis of these genes highlighted SMARCA2 and RFX3 as potential candidates for the hypoglycaemia. Targeted sequencing performed on three of the patients did not identify a second disease-causing variant within the minimal deleted region. Conclusions: This study identifies 9p deletions as an important cause of hyperinsulinaemic hypoglycaemia and increases the number of cases reported with 9p deletions and hypoglycaemia to 15 making this a more common feature of the syndrome than previously appreciated.  Whilst the precise genetic mechanism of the dysregulated insulin secretion could not be determined in these patients, mapping the deletion breakpoints highlighted potential candidate genes for hypoglycaemia within the deleted region.

Novel Preparations of Glucagon for the Prevention and Treatment of Hypoglycemia

PURPOSE OF REVIEW

New more stable formulations of glucagon have recently become available, and these provide an opportunity to expand the clinical roles of this hormone in the prevention and management of insulin-induced hypoglycemia. This is applicable in type 1 diabetes, hyperinsulinism, and alimentary hypoglycemia. The aim of this review is to describe these new formulations of glucagon and to provide an overview of current and future therapeutic opportunities that these may provide.

RECENT FINDINGS

Four main categories of glucagon formulation have been studied: intranasal glucagon, biochaperone glucagon, dasiglucagon, and non-aqueous soluble glucagon. All four have demonstrated similar glycemic responses to standard glucagon formulations when administered during hypoglycemia. In addition, potential roles of these formulations in the management of congenital hyperinsulinism, alimentary hypoglycemia, and exercise-induced hypoglycemia in type 1 diabetes have been described. As our experience with newer glucagon preparations increases, the role of glucagon is likely to expand beyond the emergency use that this medication has been limited to in the past. The innovations described in this review likely represent early examples of a pending large repertoire of indications for stable glucagon.

Proinsulin-Secreting Neuroendocrine Tumors of the Pancreas: A Single-Centre Experience

Background

Proinsulinoma is a neuroendocrine tumor (NET) of the pancreas that produces prohormone proinsulin. These tumors are very rare. In the literature, they are most often presented in the form of case reports.

Materials and Methods

We studied 177 patients with NET of the pancreas who underwent surgical treatment in the A.V. Vishnevsky National Medical Research Centre of Surgery from January 2007 to December 2018.

Results

Of 81 patients with organic hyperinsulinism caused by functioning NETs of the pancreas during the study period, 3 (3.7%) had a proinsulinoma; 2 were female; and 1 was male. None of them admitted to weight gain during this period, and their BMI was normal. All patients presented with Whipple's triad during the 72-h fast. Tumor-enucleating surgery was performed: one robot assisted, two laparotomies. A normal glucose level after treatment was achieved in all cases.

Conclusion

In cases where clinical hypoglycemia is present, but the serum insulin level is within the normal range or even decreased, proinsulinoma should be suspected. For now, surgical resection remains the only effective method of treatment. Further investigation of pro-insulinomas is needed.

Continuous Glucose Monitoring Systems: Are They Useful for Evaluating Glycemic Control in Children with Hyperinsulinism?

BACKGROUND

Effective treatment and close monitoring in children with congenital hyperinsulinism (HI) are important to prevent hypoglycemic-associated brain damage. The current monitoring approach involves measuring plasma glucose intermittently, but this does not provide a comprehensive assessment of glycemic control and may fail to detect episodes of hypoglycemia.

OBJECTIVE

To determine whether Dexcom G5®, a continuous glucose monitoring system (CGMS), is an accurate and effective method for monitoring glycemic control in children with HI.

METHODS

Cross-sectional, observational study in 15 children with HI. Participants wore a blinded Dexcom G5® device for 2 weeks. At the end of 2 weeks, data from the Dexcom G5® and home glucose meter were downloaded and analyzed.

RESULTS

Fourteen children (15-67 months) completed the study. Using Bland-Altman analysis, the mean (SD) difference between 1,155 paired CGM and glucose meter readings was -8.09 (53.76). The sensitivity and specificity of CGM to detect hypoglycemia (<70 mg/dL) were 86 and 81.4%, respectively. The positive predictive values for hypoglycemia and severe hypoglycemia (<54 mg/dL) detected by CGM were low (50.3 and 14.8%, respectively), while the negative predictive values were high (96.4% for glucose <70 mg/dL and 99.1% for glucose <54 mg/dL).

CONCLUSION

Our study showed that CGM is not a reliable method to monitor for hypoglycemia, given the high number of false positive hypoglycemia readings. However, CGM can be useful in preventing unnecessary checks by glucose meter during times of normoglycemia. Therefore, the benefits of using CGM in patients with HI would be in guiding the need to check plasma glucose by glucose meter rather than point accuracy.

Frequency and etiology of persistent neonatal hypoglycemia using the more stringent 2015 Pediatric Endocrine Society hypoglycemia guidelines

Objective

To determine if there was a significant increase in Endocrine consultations postinitiation of the more stringent 2015 guidelines for persistent neonatal hypoglycemia.

Methods

A retrospective chart review was conducted using data from November 2011 to October 2016. All infants with persistent hypoglycemia past 72 hours of life were included. Data included age, critical sample values, anthropometric measures, and maternal health. Descriptive statistical analyses were performed as was an interrupted time series analysis assuming a Poisson distribution.

Results

Fifty-eight infants were evaluated. Postintervention, there was a significant increase in the number of consults (P<0.03, 95% confidence interval [CI]: 1.14 to 8.93). Most infants with hypoglycemia persisting >72 hours were hypoglycemic shortly after birth. Half had intrauterine growth restriction; 75% were male. The median age for investigation was 8.3 days. Hyperinsulinism was the most common etiology (52/58 infants); diazoxide treatment was utilized in roughly half (29/52 to 56%) with a median duration of treatment for 91 days. The phenotype of the infants and duration of diazoxide pre- and post-Pediatric Endocrine Society protocol did not differ; two infants on diazoxide developed pulmonary hypertension. Mothers were typically of lower socioeconomic status.

Conclusion

Not surprisingly, there was significant increase in the number of infants with persistent hypoglycemia using the 2015 guidelines. Prolonged hyperinsulinism was the major cause; medical management was typically sufficient and typically well tolerated. Care to reduce adverse effects of diazoxide is advised. We postulate that infants diagnosed using the more stringent 2015 guidelines have real disease based on the protracted medical management required.

Clinical Management of Malignant Insulinoma: a single Institution's experience over three decades

BACKGROUND

Malignant insulinoma is extremely rare and accounts for only 10% of total insulinoma cases. The goal of this study is to retrospectively analyze clinical data from 15 patients with malignant insulinoma treated at Peking Union Medical College Hospital (PUMCH) from 1984 to April 2017.

METHODS

"Malignant insulinoma" was used as the keywords in the PUMCH medical record retrieval system to search and obtain patients' clinical information. We identified subjects diagnosed with malignant insulinoma based on clinical or surgical pathological signs and subsequently analyzed their clinical data.

RESULTS

Eight males and seven females with a median age at diagnosis of 40 years (38-54 years) were included. Eight patients (53%) had developed metastases at diagnosis, while the others (46.67%) developed metastases during the follow-up visits. The major sites of metastasis were the liver (86.7%), local tissues and blood vessels (33%) and abdominal lymph nodes (13%). All patients displayed neuroglycopenic (100%) and/or autonomic (60%) symptoms, mostly during fasting periods (73.3%), with an average blood glucose level of 1.66 ± 0.51 mmol/L. A total of 93% of the patients had one primary pancreatic lesion, 53% had a lesion in the head of the pancreas, and 47% had a lesion in the tail of the pancreas, with diameters ranging between 0.9 and 6.0 cm. Most liver metastases were multiple lesions. Selective celiac arteriography yielded 100% sensitivity for both primary pancreatic lesions and liver metastases. Most patients received synthetical treatments, including surgery, chemoembolization, and octreotide.

CONCLUSIONS

Malignant insulinomas have a similar diagnostic process to that of benign insulinomas but require far more comprehensive therapies to alleviate hypoglycemic symptoms and extend patients' survival.

Transient neonatal hyperinsulinaemic hypoglycaemia: perinatal predictors of length and cost of stay

Admission to neonatal care causes separation of infants from their parents, can adversely affect breast-feeding and is associated with painful procedures. Our aim was to identify perinatal factors and cost of care associated with transient neonatal hyperinsulinaemic hypoglycaemia (HH). Infants born after 35 weeks of gestation admitted because of hypoglycaemia were studied. The neonates were divided into two groups (HH and non-HH), and their length and cost of care were compared and perinatal factors predicting those outcomes explored. Forty of the 474 infants admitted with hypoglycaemia were diagnosed with HH. The HH group had a lower median (IQR) glucose level on admission compared to the non-HH group (p < 0.001). The median (IQR) cost of stay was higher in the HH group (p < 0.001). In the HH group, the GIRmax was significantly correlated with cost of stay (p < 0.001). GIRmax predicted a cost of stay > £9140 with an area under the ROC curve of 0.956. GIRmax > 13.9 mg/kg/min predicted admission cost > £9140 with 86% sensitivity and 93% specificity.Conclusion: Transient neonatal HH was associated with a higher length and cost of stay in infants admitted for hypoglycaemia. The GIRmax can predict the length and cost of stay. What is Known: • Neonatal hypoglycaemia is the leading cause of term and late preterm neonatal admissions. • Hyperinsulinism (HH) is the commonest cause of persistent hypoglycaemia, and delay in the diagnosis and management can have a detrimental impact on long-term development. What is New: • We have demonstrated prior to NICU admission that blood glucose concentrations were lower in infants with HH compared to those without. • The maximum GIR had a stronger correlation with total length and cost of hospital stay compared to insulin levels in HH infants.

An International Consortium Update: Pathophysiology, Diagnosis, and Treatment of Polycystic Ovarian Syndrome in Adolescence

This paper represents an international collaboration of paediatric endocrine and other societies (listed in the Appendix) under the International Consortium of Paediatric Endocrinology (ICPE) aiming to improve worldwide care of adolescent girls with polycystic ovary syndrome (PCOS)1. The manuscript examines pathophysiology and guidelines for the diagnosis and management of PCOS during adolescence. The complex pathophysiology of PCOS involves the interaction of genetic and epigenetic changes, primary ovarian abnormalities, neuroendocrine alterations, and endocrine and metabolic modifiers such as anti-Müllerian hormone, hyperinsulinemia, insulin resistance, adiposity, and adiponectin levels. Appropriate diagnosis of adolescent PCOS should include adequate and careful evaluation of symptoms, such as hirsutism, severe acne, and menstrual irregularities 2 years beyond menarche, and elevated androgen levels. Polycystic ovarian morphology on ultrasound without hyperandrogenism or menstrual irregularities should not be used to diagnose adolescent PCOS. Hyperinsulinemia, insulin resistance, and obesity may be present in adolescents with PCOS, but are not considered to be diagnostic criteria. Treatment of adolescent PCOS should include lifestyle intervention, local therapies, and medications. Insulin sensitizers like metformin and oral contraceptive pills provide short-term benefits on PCOS symptoms. There are limited data on anti-androgens and combined therapies showing additive/synergistic actions for adolescents. Reproductive aspects and transition should be taken into account when managing adolescents.

Association between vitamin D status and hyperinsulinism

Aims: Some studies have suggested that vitamin D deficiency is associated with an increased risk of first trimester miscarriages, others have suggested that it is associated with an increased risk of hyperinsulinism/insulin resistance and the development of gestational diabetes. Hyperinsulinism is also thought to increase miscarriages. We investigated the association between vitamin D levels and hyperinsulinism in a cohort of recurrent miscarriage patients. Methods: Patients undergoing miscarriage investigations had insulin and vitamin D levels tested. Vitamin D levels were classified as: sufficient (≥75 nmol/L), insufficient (50-74.9 nmol/L) or deficient (<50 nmol/L). Hyperinsulinism was assessed via a 75 g oral glucose tolerance test (OGTT) with insulin studies. Results: One hundred and fifty-five patients underwent the testing. Hyperinsulinism was detected in 58.3% of the vitamin D deficient group, 38.7% of the insufficient group, and 33.3% of the sufficient group (chi-square p = .034). There were no significant associations between BMI and vitamin D levels, or BMI and hyperinsulinism. Caucasians comprised 82% of the clinic, and 67% of these women had vitamin D insufficiency/deficiency. Noncaucasians comprised 18% of the clinic but 89% of these patients had vitamin D insufficiency/deficiency. Discussion: We found that insufficient or deficient vitamin D levels were significantly associated with hyperinsulinism in these patients. Vitamin D deficiency is also thought to contribute to an increased risk of adverse pregnancy outcomes including preeclampsia, preterm birth, small-for-gestational-age gestational diabetes mellitus, and miscarriages. Larger level one trials are needed to establish if increasing serum vitamin D levels prior to conception or in early pregnancy improves adverse pregnancy outcomes.

Randomised controlled trial of diazoxide for small for gestational age neonates with hyperinsulinaemic hypoglycaemia provided early hypoglycaemic control without adverse effects

AIM

Hyperinsulinaemic hypoglycaemia (HH) is a very common cause of hypoglycaemia in small for gestational age (SGA) neonates. We compared using early oral diazoxide or a placebo for this patient group.

METHODS

This was a randomised, double-blind, placebo-controlled trial that focused on SGA neonates born at at least 32 weeks of gestation with HH during the first five days of life. Neonates with severe perinatal asphyxia, sepsis or contraindications for oral feeds were excluded. The primary outcome was the hours taken to achieve hypoglycaemic control, with a glucose infusion rate of ≤4 mg/kg/min. The secondary outcomes were the duration of intravenous fluids, sepsis episodes, time to achieve full feeds and mortality.

RESULTS

We screened 490 neonates and 30 neonates were eligible for randomisation and completed the trial. Half received diazoxide and half received a placebo. The median time to achieve hypoglycaemia control (40 vs 71.5 hours, p = 0.015), the total duration of intravenous fluids (114 vs 164 hours, p = 0.04) and time to achieve full feeds (74 vs 124 hours, p = 0.02) were significantly lower in the diazoxide group, with no adverse effects attributed to the drug.

CONCLUSION

Using oral diazoxide for SGA neonates with HH provided early hypoglycaemic control with no apparent adverse effects.

The Value of Prostate-Specific Antigen in Diagnosis of Polycystic Ovarian Syndrome in Adolescent Girls

STUDY OBJECTIVE

This study was designed to evaluate and compare the serum total prostate-specific antigen (PSA) levels in adolescent girls in with and without polycystic ovarian syndrome (PCOS) to show whether evaluation of PSA levels have a diagnostic benefit over existing diagnostic criteria.

DESIGN

Case-control study.

SETTING

A territory referral center.

PARTICIPANTS

A total of 89 (15-19 years) nonobese (body mass index, 18-24.9) adolescents with PCOS (n = 42) and controls without PCOS (n = 47) were enrolled in the study.

INTERVENTIONS

Pathophysiological features of PCOS and serum total PSA levels were determined at the time of study enrollment.

MAIN OUTCOME MEASURES

Determination, comparison, and diagnostic performance of serum total PSA levels in diagnosis of PCOS in adolescent girls were the main outcome measures of the study.

RESULTS

The serum total PSA levels of adolescents with PCOS were detected to be higher than for control participants (0.63 ± 1.38 ng/mL vs 0.48 ± 0.95 ng/mL) without meeting statistical significance (P = .923). There was a correlation between total PSA levels and indices of insulin resistance like the homeostasis insulin resistance model (r = 0.414; P = .010). The serum total PSA level was not a discriminative parameter for diagnosis of PCOS in adolescent girls (area under the curve, 0.559; P = .476).

CONCLUSION

The serum total PSA level was not a predictor of PCOS in adolescent girls. This finding might be related to the extemporal nature of tissues capable of PSA production and lack of sufficient exposure interval to hyperandrogenemia, rather than lack of stimulatory relationship between serum androgens.

Continuous Flash Glucose Monitoring in children with Congenital Hyperinsulinism; first report on accuracy and patient experience

Background

The factory calibrated FreeStyle Libre (FSL) flash glucose monitoring system has been recently introduced for use in patients with diabetes mellitus. There are no reports available regarding its use in patients with congenital hyperinsulinism (CHI). We have assessed the accuracy of FSL compared to the finger prick capillary blood glucose (CBG) over 2 weeks period in patients with CHI and evaluated the parents’ experience of using FSL.

Methods

Four hundred sixty-seven episodes of CBG along with corresponding swipe FSL readings were available from 11 children with CHI (0.5–5 years). A detailed questionnaire was completed by the parents.

Results

The mean variation between the two methods was 0.29 mmol/l (SD ±1.07), higher readings by FSL compared to CBG. The FSL sensors stayed in-situ for an average period of 11.5 days. There was a positive correlation between the two methods (r = 0.7). The FSL tended to overestimate compared to CBG (bias = 0.29 mmol/l; 95% CI: 0.19 to 0.38). Only 70% of values were within the reference standard (±0.83 mmol/l) at glucose concentrations less than 5.6 mmol/l. The overall Mean Absolute Relative Difference (MARD) was 17.9%. Forty two episodes of hypoglycaemia (CBG < 3.5 mmol/l) were noted but FSL identified only 52% of these episodes. The Bland Altman analysis showed the 95% limits of agreement between the two methods ranging from − 1.8 (95% CI: -1.97 to − 1.64) to 2.37 (95% CI: 2.21 to 2.54). Majority of the parents found the glucose trend on FSL to be useful to detect and prevent hypoglycaemic episodes. All parents felt that FSL is a very easy and convenient method to measure the glucose especially during sleep. A significant proportion of parents felt that FSL readings were not accurate and 56% of parents expressed interest to continue using FSL after the trial period.

Conclusion

Noticeable variability between the two methods of measuring the glucose was noted. Despite the ease of using the FSL system, concerns related to accuracy, especially at low glucose values do remain although parents find the glucose trend to be very useful. Further larger trials are needed in CHI patients before FSL is recommended as a routine alternative method for measuring glucose levels.

Hyperinsulinism in the Neonate

Hyperinsulinism (HI) is the leading cause of persistent hypoglycemia in infants. Prompt recognition and treatment, independent of whether infants have transient or permanent HI, are essential to decrease risk of neurologic damage. The most common form of congenital HI is due to inactivating mutations of the β-cell ATP-sensitive potassium (K_ATP) channel (K_ATP-HI) and is typically diazoxide unresponsive. K_ATP-HI occurs in diffuse and focal forms. Distinguishing between the 2 forms is crucial, because pancreatectomy is curative in the focal form but palliative in the diffuse form. The 18-fluoro-L-3,4-dihydroxyphenylalanine PET scan has revolutionized HI management by allowing accurate localization of focal lesions prior to surgery.