Congenital hyperinsulinism: current status and future perspectives

Congenital hyperinsulinemic hypoglycaemia in a neonate: a rare homozygous ABCC8 gene mutation

Hyperinsulinemic hypoglycaemia (HH) is a heterogeneous disorder causing persistent hypoketotic hypoglycaemia in neonates and infants. Congenital hyperinsulinism (CHI) is a rare cause of HH, resulting from inappropriate insulin secretion by pancreatic β-cells due to genetic defects in key genes, notably ABCC8 and KCNJ11, which encode the SUR1 and Kir6.2 components of the KATP channels, respectively. We present a case of a neonate with congenital HH with persistent hypoglycaemia since birth, which was managed with high-dose glucose infusions, diazoxide and octreotide. A homozygous pathogenic missense variant, c4253G>A (p.Arg1418His) in Exon 35 of the ABCC8 gene was identified in the neonate, confirming CHI. Despite initial refractoriness to treatment, the infant responded to octreotide therapy, cornstarch and careful management with regular feeds and monitoring, avoiding the need for surgical intervention. This case underscores the critical role of genetic diagnosis and timely management in preventing long-term neurological sequelae.

A novel mutation in the KCNJ11 gene (p.Val36Glu), predisposes to congenital hyperinsulinemia

The hypoglycemia induced by insulin hypersecretion in congenital hyperinsulinemia (CHI), a rare life-threatening condition can lead to irreversible brain damage in neonates. Inactivating mutations in the genes encoding K_ATP channel (ABCC8 and KCNJ11) as well as HNF4A, HNF1A, HADH, UCP2, and activating mutations in GLUD1, GCK, and SLC16A1 have been identified as causal. A 3-month-old male infant presenting tonic-clonic seizures and hyperinsulinemia was clinically assessed and subjected to genetic analysis. Besides the index patient, his parents were clinically investigated, and a detailed family history was also recorded. The laboratory investigations and the genetic test results of the parents were compared with the index patient. The biochemical and hormonal profile of the patient confirmed his suffering from CHI and did not respond to diazoxide treatment. The genetic testing revealed that the subject harbored a novel homozygous missense mutation in the KCNJ11 gene, (c.107T>A, p.Val36Glu.). The bioinformatic analysis revealed that valine is highly conserved and predicted that the variant allele (p.Val36Glu) is likely pathogenic and causal for CHI. Parents were heterozygous carriers and did not report any abnormal metabolic profile. Identification of such mutations is critical and likely to change the therapeutic interventions for such patients in the future.

Glutamate dehydrogenase hyperinsulinism: mechanisms, diagnosis, and treatment

Congenital hyperinsulinism (CHI) is a genetically heterogeneous disease, in which intractable, persistent hypoglycemia is induced by excessive insulin secretion and increased serum insulin concentration. To date,15 genes have been found to be associated with the pathogenesis of CHI. Glutamate dehydrogenase hyperinsulinism (GDH-HI) is the second most common type of CHI and is caused by mutations in the glutamate dehydrogenase 1 gene. The objective of this review is to summarize the genetic mechanisms, diagnosis and treatment progress of GDH-HI. Early diagnosis and treatment are extremely important to prevent long-term neurological complications in children with GDH-HI.

Discovery of 4-(3-aminopyrrolidinyl)-3-aryl-5-(benzimidazol-2-yl)-pyridines as potent and selective SST5 agonists for the treatment of congenital hyperinsulinism

SST5 receptor activation potently inhibits insulin secretion from pancreatic β-cells, and an orally available nonpeptide selective SST5 agonist may be used to effectively manage the blood glucose levels of congenital HI patients to avoid severe hypoglycemia. Our medicinal chemistry efforts have led to the discovery of 4-(3-aminopyrrolidinyl)-3-aryl-5-(benzimidazol-2-yl)-pyridine analogs as potent SST5 agonists. This class of molecules exhibits excellent human SST5 potency and selectivity against SST1, SST2, SST3 and SST4 receptors. Leading compound 3-{4-[(3S)-3-aminopyrrolidin-1-yl]-5-(4-methyl-1H-1,3-benzodiazol-2-yl)pyridin-3-yl-5-fluorobenzonitrile (28, CRN02481) showed limited off-target activity and good pharmacokinetic profiles in both male Sprague Dawley rats and Beagle dogs to advance into further preclinical evaluations.

Investigating Genetic Mutations in a Large Cohort of Iranian Patients with Congenital Hyperinsulinism

OBJECTIVE

Congenital hyperinsulinism (CHI) is the most frequent cause of severe and persistent hypoglycaemia from birth. Understanding the pathophysiology and genetic defects behind hyperinsulinism and its complications provides clues to timely diagnosis and management. The aim of this study was to evaluate the underlying genetic aetiology of a specific Iranian pediatric cohort with CHI.

METHODS

A total of 44 unrelated children, 20 girls and 24 boys, with an initial diagnosis or history of CHI from all regions of Iran were recruited between 2016 and 2019. Targeted next generation sequencing (tNGS) was performed for the genes found in about half of CHI patients.

RESULTS

Mutations were identified in 24 cases (55%). Patients with a confirmed genetic cause were mainly diagnosed below age of one year old (p=0.01), had fewer other syndromic features, excluding seizure, (p=0.03), were less diazoxide responsive (p=0.04) and were more diazoxide unresponsive leading to pancreatectomy (p=0.007) compared to those with no identified mutations. Among 24 patients with identified genetic mutations, 17 (71%) had a mutation in ABCC8, 3 (12%) in KCNJ11, 3 (12%) in HADH, and 1 patient had a mutation in KMT2D. These included five novel mutations in ABCC8, KCNJ11, and KMT2D.

CONCLUSION

This is the biggest genetic study of CHI in Iran. A high frequency of recessive forms of CHI, especially HADH mutations, in our study could be due to a high rate of consanguineous marriage. We recommend tNGS to screen for all the CHI genes.

Molecular Characterization and Management of Congenital Hyperinsulinism: A Tertiary Centre Experience

Background

Objective

Study design

Participants

Outcomes

Results

Conclusions

Electronic Supplementary Material

Health-Related Quality of Life of Children and Adolescents With Congenital Hyperinsulinism - A Scoping Review

Introduction

Despite improvements in diagnosis and therapeutic advances in treatment, congenital hyperinsulinism (CHI) remains a severe disease with high patient impairment. We aimed to review the literature on Health-related Quality of Life in children and adolescents with congenital hyperinsulinism and summarize the findings.

Materials and Methods

For this scoping review, a literature search was conducted in PubMed and Web of Science in May 2021. Inclusion and exclusion criteria for the selection of articles were defined a priori.

Results

Two hundred and forty-five (245) articles were identified through the search and screened on the basis of title and abstract. The full texts of forty articles were then assessed. Finally, four articles (published 2012-2020) describing Health-related Quality of Life in children and adolescents with congenital hyperinsulinism were included. The study designs were heterogeneous and included cross-sectional observational studies (n=2), clinical trials (n =1), and case reports (n=1) with different sample sizes. Three studies were conducted in European countries and one in Japan. The results for Health-related Quality of Life revealed inconsistencies.

Conclusion

There are only a few studies looking at Health-related Quality of Life in children and adolescents with congenital hyperinsulinism. To gain a comprehensive understanding of the impact of congenital hyperinsulinism on Health-related Quality of Life in children and adolescents, it is necessary to use both generic and condition-specific instruments to measure Health-related Quality of Life of young patients in larger samples, to collect longitudinal data, and to consider qualitative research approaches.

Diazoxide-Induced Neutropenia and Long-Term Follow-up in a Patient with Hyperinsulinemia-Hyperammonemia due to GLUD1 Mutation

Hyperinsulinism/hyperammonemia (HI/HA) syndrome is caused by activating mutations in GLUD1 gene, and causes fasting as well as protein sensitive symptomatic hypoglycemia, in addition to persistently elevated plasma ammonia levels. First-line treatment is diazoxide, and most patients respond well to this agent, however side effects may be observed. The most frequent side effect of diazoxide is fluid retention and hypertrichosis, while hyperuricemia and hematologic side effects are observed less often. Herein, we report a case who had a heterozygous mutation of GLUD1 gene and who developed diazoxide related neutropenia 8 years after the start of treatment. On follow-up, leucopenia and mild neutropenia persisted and the treatment was changed to somatostatin analogues. However, she developed persistent severe symptomatic hypoglycemia and required diazoxide retreatment. A lower dose of diazoxide (6 mg/kg/day) successfully controlled hypoglycemia and cell counts increased even though they were not normalized. Neutropenia in current case presented after a long period of time of diazoxide use and this period is the longest defined in the literature. Long-term endocrine and hematologic follow-up of this patient up to 18 years old will also be presented.

Analysis of clinical and genetic characteristics of Chinese children with congenital hyperinsulinemia that is spontaneously relieved

OBJECTIVE

This study aimed to analyze the clinical and genetic characteristics of Chinese children with congenital hyperinsulinemia (CHI) that is spontaneously relieved.

METHODS

The patient group comprised 200 children with CHI that were treated at the Beijing Children's Hospital from January 2006 to December 2018. The patients were divided into two groups according to their prognosis: the spontaneous remission group (n = 92) and the nonspontaneous remission group (n = 108). The clinical characteristics, pathogenic genes, diagnosis and treatment process, and follow-up data of both groups were analyzed retrospectively.

RESULTS

Of the 200 children with CHI, 92 achieved spontaneous remission. The age of spontaneous remission was between one month and nine years, and 47 of the children were relieved before the age of one year. The median age of onset was 85 days (range: 1-2825 days) in the spontaneous remission group and 2 days (range: 1-210 days) in the nonspontaneous remission group (P < 0.05). The mean birth weight was 3.44 ± 0.76 kg for the spontaneous remission group and 3.95 ± 0.75 kg for the nonspontaneous remission group (P < 0.05). Of the 92 children in the spontaneous remission group, 65 were treated with diazoxide with effective rate of 81.5% (53/65). In 12 cases in which diazoxide treatment failed, octreotide was used with an effective rate of 83.3% (10/12). Of the 108 children in the nonspontaneous remission group, 88 were treated with diazoxide with an effective rate of 43.2 % (38/88), and 29 children were treated with octreotide with an effective rate of 48.28% (14/29). Of the 30 children in the spontaneous remission group that underwent mutation analysis of CHI-related pathogenic genes, 10 children (10/30, 33.3%) carried mutations. Of the 48 children in the nonspontaneous remission group that underwent mutation analysis of CHI-related pathogenic genes, 37 children (37/48, 77.1%) were found to carry mutations. All of the differences in the indices mentioned above were statistically significant.

CONCLUSIONS

The rate of spontaneous remission of CHI was significantly higher in children with late age of CHI onset, light birth weight, effective diazoxide treatment, and no common pathogenic gene mutations. Spontaneous remission was also possible for a small number of children that carried mutations in the ABCC and KCNJ11 genes and in whom diazoxide treatment failed.

Long-Term Outcome and Treatment in Persistent and Transient Congenital Hyperinsulinism: A Finnish Population-Based Study

CONTEXT

The management of congenital hyperinsulinism (CHI) has improved.

OBJECTIVE

To examine the treatment and long-term outcome of Finnish patients with persistent and transient CHI (P-CHI and T-CHI).

DESIGN

A population-based retrospective study of CHI patients treated from 1972 to 2015.

PATIENTS

106 patients with P-CHI and 132 patients with T-CHI (in total, 42 diagnosed before and 196 after year 2000) with median follow-up durations of 12.5 and 6.2 years, respectively.

MAIN OUTCOME MEASURES

Recovery, diabetes, pancreatic exocrine dysfunction, neurodevelopment.

RESULTS

The overall incidence of CHI (n = 238) was 1:11 300 live births (1972-2015). From 2000 to 2015, the incidence of P-CHI (n = 69) was 1:13 500 and of T-CHI (n = 127) 1:7400 live births. In the 21st century P-CHI group, hyperinsulinemic medication was initiated and normoglycemia achieved faster relative to earlier. Of the 74 medically treated P-CHI patients, 68% had discontinued medication. Thirteen (12%) P-CHI patients had partial pancreatic resection and 19 (18%) underwent near-total pancreatectomy. Of these, 0% and 84% developed diabetes and 23% and 58% had clinical pancreatic exocrine dysfunction, respectively. Mild neurological difficulties (21% vs 16%, respectively) and intellectual disability (9% vs 5%, respectively) were as common in the P-CHI and T-CHI groups. However, the 21st century P-CHI patients had significantly more frequent normal neurodevelopment and significantly more infrequent diabetes and pancreatic exocrine dysfunction compared with those diagnosed earlier.

CONCLUSIONS

Our results demonstrated improved treatment and long-term outcome in the 21st century P-CHI patients relative to earlier.

Congenital hyperinsulinism: 2 case reports with different rare variants in ABCC8

Congenital hyperinsulinism (CHI) is a rare glucose metabolism disorder characterized by unregulated secretion of insulin that leads to hyperinsulinemic hypoglycemia (HH). Most cases are caused by mutations in the KATP-channel genes ABCC8 and KCNJ11. We report 2 patients that experienced severe HH from the first day of life. Patient 1 developed midgut volvulus after initiating diazoxide and required intestinal resection. He was subsequently managed with a high-dose octreotide and glucose-enriched diet. Consistent with diffuse type CHI by 18F-dihydroxyphenylalanine positron emission tomography-computed tomography, genetic testing revealed a homozygous ABCC8 variant, c.1801G>A, p.(Val601Ile). The rare variant was previously reported to be diazoxide-responsive, and the patient responded well to diazoxide monotherapy, with clinical remission at 2 years of age. Patient 2 responded to diazoxide with spontaneous clinical remission at 15 months of age. However, an oral glucose tolerance test at 7 years of age revealed hyperinsulinism. Genetic testing revealed that the proband and several seemingly healthy family members harbored a novel, heterozygous ABCC8 variant, c.1780T>C, p.(Ser594Pro). Genetic findings identified previously unrecognized HH in the proband's mother. The proband's uncle had been diagnosed with monogenic ABCC8-diabetes and was successfully transitioned from insulin to glibenclamide therapy. We report findings of intestinal malrotation and volvulus occurring 2 days after initiation of diazoxide treatment. We also report a novel, heterozygous ABCC8 variant in a family that exhibited cases of CHI in infancy and HH and monogenic diabetes in adult members. The cases demonstrate the importance and clinical utility of genetic analyses for informing and guiding treatment and care.

Sato A. Functional GLP-1R antibodies identified from a synthetic GPCR-focused library demonstrate potent blood glucose control

G protein-coupled receptors (GPCRs) are a group of seven-transmembrane receptor proteins that have proven to be successful drug targets. Antibodies are becoming an increasingly promising modality to target these receptors due to their unique properties, such as exquisite specificity, long half-life, and fewer side effects, and their improved pharmacokinetic and pharmacodynamic profiles compared to peptides and small molecules, which results from their more favorable biodistribution. To date, there are only two US Food and Drug Administration-approved GPCR antibody drugs, namely erenumab and mogamulizumab, and this highlights the challenges encountered in identifying functional antibodies against GPCRs. Utilizing Twist's precision DNA writing technologies, we have created a GPCR-focused phage display library with 1 × 1010 diversity. Specifically, we mined endogenous GPCR binding ligand and peptide sequences and incorporated these binding motifs into the heavy chain complementarity-determining region 3 in a synthetic antibody library. Glucagon-like peptide-1 receptor (GLP-1 R) is a class B GPCR that acts as the receptor for the incretin GLP-1, which is released to regulate insulin levels in response to food intake. GLP-1 R agonists have been widely used to increase insulin secretion to lower blood glucose levels for the treatment of type 1 and type 2 diabetes, whereas GLP-1 R antagonists have applications in the treatment of severe hypoglycemia associated with bariatric surgery and hyperinsulinomic hypoglycemia. Here we present the discovery and creation of both antagonistic and agonistic GLP-1 R antibodies by panning this GPCR-focused phage display library on a GLP-1 R-overexpressing Chinese hamster ovary cell line and demonstrate their in vitro and in vivo functional activity.

Intraoperative ultrasound imaging in the surgical treatment of congenital hyperinsulinism: prospective, blinded study

Background

In congenital hyperinsulinism (CHI), preoperative prediction of the histological subtype (focal, diffuse, or atypical) relies on genetics and 6-[¹⁸F]fluoro-l-3,4-dihydroxyphenylalanine (¹⁸F-DOPA) PET–CT. The scan also guides the localization of a potential focal lesion along with perioperative frozen sections. Intraoperative decision-making is still challenging. This study aimed to describe the characteristics and potential clinical impact of intraoperative ultrasound imaging (IOUS) during CHI surgery.

Methods

This was a prospective, observational study undertaken at an expert centre over a 2-year interval. IOUS was performed blinded to preoperative diagnostic test results (genetics and ¹⁸F-DOPA PET–CT), followed by unblinding and continued IOUS during pancreatic resection. Characteristics and clinical impact were assessed using predefined criteria.

Results

Eighteen consecutive, surgically treated patients with CHI, with a median age of 5.5 months, were included (focal 12, diffuse 3, atypical 3). Focal lesions presented as predominantly hypoechoic, oval lesions with demarcated or blurred margins. Patients with diffuse and atypical disease had varying echogenicity featuring stranding and non-shadowing hyperechoic foci in three of six, whereas these characteristics were absent from those with focal lesions. The blinded IOUS-based subclassification was correct in 17 of 18 patients; one diffuse lesion was misclassified as focal. IOUS had an impact on the surgical approach in most patients with focal lesions (9 of 12), and in those with diffuse (2 of 3) and atypical (2 of 3) disease when the resection site was close to the bile or pancreatic duct.

Conclusion

Uniform IOUS characteristics made all focal lesions identifiable. IOUS had a clinical impact in 13 of 18 patients by being a useful real-time supplementary modality in terms of localizing focal lesions, reducing the need for frozen sections, and preserving healthy tissue and delicate structures.

Diagnosis of congenital Hyperinsulinism can occur not only in infancy but also in later age: a new flow chart from a single center experience

BACKGROUND

Congenital Hyperinsulinism typically occurs with a neonatal hypoglycemia but can appear even in childhood or in adolescence with different types of glucose metabolism derangements. Current diagnostic algorithms don't take into account cases with a late presentation.

PATIENTS AND METHODS

Clinical and laboratory data of twenty-two subjects diagnosed at Federico II University of Naples have been described: patients have been divided according to the molecular defect into channel defects, metabolic defects and unidentified molecular defects. A particular focus has been made on three cases with a late presentation.

RESULTS AND CONCLUSIONS

Late presentation cases may not be identified by previous diagnostic algorithms. Consequently, it seems appropriate to design a new flow-chart starting from the age of presentation, also considering that late presentation cases can show glucose metabolism derangements other than hypoglycaemic crises such as diabetes, glucose intolerance, postprandial hypoglycaemia and gestational diabetes.

Suspected congenital hyperinsulinism in a Shiba Inu dog

A 3‐month‐old male intact Shiba Inu dog was evaluated for a seizure disorder initially deemed idiopathic in origin. Seizure frequency remained unchanged despite therapeutic serum phenobarbital concentration and use of levetiracetam. The dog was documented to be markedly hypoglycemic during a seizure episode on reevaluation at 6 months of age. Serum insulin concentrations during hypoglycemia were 41 U/μL (reference range, 10‐29 U/μL). The dog was transitioned to 4 times per day feeding, diazoxide was started at 3.5 mg/kg PO q8h, and antiepileptic drugs were discontinued. No clinically relevant abnormalities were identified on bicavitary arterial and venous phase contrast computed tomographic imaging. The dog remained seizure‐free and clinically normal at 3 years of age while receiving 5.5 mg/kg diazoxide PO q12h and twice daily feeding. Seizures later occurred approximately twice per year and after exertion, with or without vomiting of a diazoxide dose. Blood glucose curves and interstitial glucose monitoring were used to titrate diazoxide dose and dosing interval. Congenital hyperinsulinism is well recognized in people but has not been reported in veterinary medicine.

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.

Hyperinsulinism associated with GLUD1 mutation: allosteric regulation and functional characterization of p.G446V glutamate dehydrogenase

Background

Gain-of-function mutations in the GLUD1 gene, encoding for glutamate dehydrogenase (GDH), result in the hyperinsulinism/hyperammonemia HI/HA syndrome. HI/HA patients present with harmful hypoglycemia secondary to protein-induced HI and elevated plasma ammonia levels. These symptoms may be accompanied by seizures and mental retardation. GDH is a mitochondrial enzyme that catalyzes the oxidative deamination of glutamate to α-ketoglutarate, under allosteric regulations mediated by its inhibitor GTP and its activator ADP. The present study investigated the functional properties of the GDH-G446V variant (alias c.1496G > T, p.(Gly499Val) (NM_005271.4)) in patient-derived lymphoblastoid cells.

Results

The calculated energy barrier between the opened and closed state of the enzyme was 41% lower in GDH-G446V compared to wild-type GDH, pointing to altered allosteric regulation. Computational analysis indicated conformational changes of GDH-G446V in the antenna region that is crucial for allosteric regulators. Enzymatic activity measured in patient-derived lymphoblastoid cells showed impaired allosteric responses of GDH-G446V to both regulators GTP and ADP. In particular, as opposed to control lymphoblastoid cells, GDH-G446V cells were not responsive to GTP in the lower range of ADP concentrations. Assessment of the metabolic rate revealed higher mitochondrial respiration in response to GDH-dependent substrates in the GDH-G446V lymphoblastoid cells compared to control cells. This indicates a shift toward glutaminolysis for energy provision in cells carrying the GDH-G446V variant.

Conclusions

Substitution of the small amino acid glycine for the hydrophobic branched-chain valine altered the allosteric sensitivity to both inhibitory action of GTP and activation by ADP, rendering cells metabolically responsive to glutamine.

Diazoxide-induced pulmonary hypertension in hyperinsulinaemic hypoglycaemia: Recommendations from a multicentre study in the United Kingdom

OBJECTIVE

Diazoxide is first-line treatment for hyperinsulinaemic hypoglycaemia (HH) but diazoxide-induced pulmonary hypertension (PH) can occur. We aim to characterize the incidence and risk factors of diazoxide-induced PH in a large HH cohort to provide recommendations for anticipating and preventing PH in diazoxide-treated patients with HH.

DESIGN AND PATIENTS

Retrospective cohort study involving four UK regional HH centres; review of case notes of HH patients on diazoxide.

MEASUREMENTS

The diagnosis of PH was based on clinical and echocardiography evidence. Patient and treatment-related risk factors were analysed for association.

RESULTS

Thirteen (6 men) of 177 HH diazoxide-treated patients developed PH, an incidence of 7%. In the PH group, HH was diagnosed at median (range) of 9 (1,180) days, with diazoxide commenced 4 (0,76) days from diagnosis and reaching a maximum dose of 7 (2.5,20) mg/kg/d. The majority (8 of 13 patients) developed PH within 2 weeks of diazoxide. Complete diazoxide withdrawal, but not dose reduction, led to PH resolution at 41 (3,959) days. In three patients, PH continued beyond 12 months. Risk factors for the development of PH included the presence of congenital heart disease (CHD) (P = .008), and total fluid volume exceeding 130 mL/kg/d in the immediate 24 hours preceding diazoxide (P = .019).

CONCLUSION

Pulmonary hypertension can occur in 7% of diazoxide-treated HH patients. Risk factors include the presence of congenital heart disease and fluid overload. Recommendations include echocardiography and fluid restriction to 130 mL/kg/d prior to diazoxide treatment and immediate discontinuation of diazoxide if PH develops.

A case report of type 1 diabetes mellitus and factitious hypoglycemia in a patient with Munchausen Syndrome

Munchausen syndrome is rarely considered as a first diagnosis, especially in a type 1 diabetic patient presenting with hyperinsulinemic hypoglycemia. The diagnosis should be considered when episodes of hypoglycemia are persistent, and tests suggest a possible exogenous source of insulin. We report a case of a 26-year-old man with multiple hypoglycemic episodes and a long known diagnosis of diabetes type 1 who was referred to our institution after multiple in and out patient consultations in other institutions. He arrived with persistent hypoglycemia, even after withdrawal of insulin therapy on medical record, but persistent self-administration and misuse, without health care professional knowledge, of insulin therapy. He was diagnosed with factitious hypoglycemia after psychiatric evaluation. The patient improved with psychotherapy and family support as well as strict vigilance of insulin administration.

Management of hypoglycemia in newborn: Turkish Neonatal and Pediatric Endocrinology and Diabetes Societies consensus report

Hypoglycemia is one of the most important and most common metabolic problems of the newborn because it poses a risk of neurological injury, if it is prolonged and recurs. Therefore, newborns who carry a risk of hypoglycemia should be fed immediately after delivery and the blood glucose level should be measured with intervals of 2-3 hours from the 30^th minute after feeding. The threshold value for hypoglycemia is 40 mg/dL for the first 24 hours in symptomatic babies. In asymptomatic babies, this value is considered 25 mg/dL for 0-4 hours, 35 mg/dl for 4-24 hours, 50 mg/dL after 24 hours and 60 mg/dL after 48 hours. Screening should be performed with bed-side test sticks. When values near the limit value are obtained, confirmation with laboratory method should be done and treatment should be initiated, if necessary. The level targeted with treatment is considered 50 mg/dL in the postnatal first 48 hours before feeding, 60 mg/dL after 48 hours in babies with high risk and above 70 mg/dL in babies with permanent hypoglycemia. In cases in which the blood glucose level is below the threshold value and can not be increased by feeding, a glucose infusion of 6-8 mg/kg/min should be initiated. If symptoms accompany, a mini bolus of 10% dextrose (2 ml/kg/min) should accompany. Incements (2 mg/kg/min) should be performed, if the target level can not be achieved and decrements (2 ml/kg/ min) should be performed, if nutrition and stabilization is provided. The infusion should be discontinued, if the infusion rate decreases to 3-5 mg/ kg/min. If necessary, blood samples should be obtained during hypoglycemia in terms of differential diagnosis and the investigation should be performed following a 6-hour fasting period in babies fed enterally and at any time when the plasma glucose is <50 mg/dL in babies receiving parenteral infusion. The hypoglycemic babies in the risk group whose infusions have been terminated can be discharged, if the plasma glucose level is found to be at the target level for two times before feeding and babies with permanent, severe or resistant hypoglycemia can be discharged, if the plasma glucose level is >60 mg/dL following a 6-hour fast.

Current and Emerging Agents for the Treatment of Hypoglycemia in Patients with Congenital Hyperinsulinism

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycmia in neonatles and children. The inappropriate secretion of insulin by the pancreatic β-cells produces recurrent hypoglycemia, which can lead to severe and permanent brain damage. CHI results from mutations in different genes that play a role in the insulin secretion pathway, and each differs in their responsiveness to medical treatment. Currently, the only available approved treatment for hyperinsulinism is diazoxide. Patients unresponsive to diazoxide may benefit from specialized evaluation including genetic testing and 18F-DOPA PET to identify those with focal forms of CHI. The focal forms can be cured by selective pancreatectomy, but the management of diazoxide-unresponsive diffuse CHI is a real therapeutic challenge. Current off-label therapies include intravenous glucagon, octreotide and long-acting somatostatin analogs; however, they are often insufficient, and a 98% pancreatectomy or continuous feeds may be required. For the first time in over 40 years, new drugs are being developed, but none have made it to market yet. In this review, we will discuss current on-label and off-label drugs and review the currently available data on the novel drugs under development.

Congenital hyperinsulinism in two siblings with ABCC8 mutation: same genotype, different phenotypes

Congenital hyperinsulinism (CHI) is a heterogenous disease caused by insulin secretion regulatory defects, being ABCC8/KCNJ11 the most commonly affected genes. Therapeutic options include diazoxide, somatostatin analogues and surgery, which is curative in focal CHI. We report the case of two siblings (born two years apart) that presented themselves with hypoketotic hyperinsulinemic persistent hypoglycemias during neonatal period. The diagnosis of diffuse CHI due to an ABCC8 compound mutation (c.3576delG and c.742C>T) was concluded. They did not benefit from diazoxide therapy (or pancreatectomy performed in patient number 1) yet responded to somatostatin analogues. Patient number 1 developed various neurological deficits (including epilepsy), however patient number 2 experienced an entirely normal neurodevelopment. We believe this case shows how previous knowledge of the firstborn sibling's disease contributed to a better and timelier medical care in patient number 2, which could potentially explain her better neurological outcome despite their same genotype.

The burden of congenital hyperinsulinism in the United Kingdom: a cost of illness study

BACKGROUND

Congenital hyperinsulinism (CHI) is a rare, genetic disease which causes persistent hypoglycaemia, typically in new-borns. Patients with the diffuse disease variant often require near-total surgical removal of the pancreas, causing insulin-dependent diabetes mellitus (IDDM). The CHI economic burden is currently unknown. This study aimed to estimate the annual cost of illness (COI) of CHI patients in the UK from a service provider perspective (National Health Service, NHS and Personal Social Services), and to explore cost distribution within the patient population.

METHODS

The model was based on standard practice of two CHI centres of excellence. Model inputs were informed by a pragmatic literature review, NHS Reference Costs (2015-2016) and the British National Formulary (2017). Only direct costs to the NHS and Personal Social Services were considered. A prevalence-based approach was used and annual costs incurred at all ages were calculated. A deterministic sensitivity analysis (DSA; run at 10%) identified major cost drivers.

RESULTS

The COI of CHI patients to the NHS was £3,408,398.59 annually and average cost per patient was £2124.95. Cost distribution was skewed among CHI patients, with 5.9% of patients (95 patients in their first year of life) contributing to 61.8% (£2,105,491.07) of total costs. DSA results identified lack of response to first-line therapy and IDDM development post surgery (and associated healthcare costs) as major cost drivers.

CONCLUSIONS

Despite its rare disease status, estimated annual costs of CHI to the NHS were substantial. Development and management of post-surgical IDDM as a major cost driver highlights the need for effective treatments to mitigate such consequences and costs.

Association of maternal nutrition with transient neonatal hyperinsulinism

Objective

The objective was to determine whether maternal nutritional factors are associated with transient neonatal hyperinsulinism (HI).

Design and setting

Case control study in 4 French tertiary Obstetrics and Neonatology Departments between 2008 and 2015.

Methods

Sixty-seven mothers of neonates diagnosed with transient hyperinsulinism and 113 mothers of controls were included. The screening for hyperinsulinemic hypoglycemia in neonates was performed because of clinical symptoms suggestive of hypoglycemia or in the presence of conventional risk factors (small-for-gestational-age, prematurity, anoxo-ischemia, hypothermia, macrosomia, gestational diabetes). Hyperinsulinemic hypoglycemia was confirmed in the HI neonates and ruled out in the controls. This allowed for comparing maternal nutrition in cases and controls in a context of similar risk factors. One to 2 mothers of control neonates were included per case, and a food frequency questionnaire was addressed to the mothers between day 5 and day 10 after the birth of their newborn.

Results

Crude odds ratio showed that maternal weight gain, abnormal fetal rate, C-section, gender, consumption of fresh cooked vegetables, fresh fruits and fruit juices, low fat diary products, light fat products, and daily bread were significantly associated with hyperinsulinism. Maternal body mass index, hypertension, gestational diabetes, birth weight percentile, gestational age and 5-minute Apgar score were not related to HI. In a multiple backward logistic regression model, consumption of fresh cooked vegetable ≥1/day (OR = 0.33 [0.14–0.77]) and light-fat products ≥1/week (OR = 0.24 [0.08–0.71]) was protective against hyperinsulinism, whereas gestational weight gain >20 kg (OR = 9.5 [2.0–45.5]) and between 15–20 kg (OR = 4.0 [1.2–14.0]), abnormal fetal heart rate (OR = 4.4 [1.6–12.0]), and C-section (OR = 3.4 [1.3–8.9]) were risk factors.

Conclusions

A diet rich in fresh cooked vegetable and reduced in fat, together with the avoidance of a high gestational weight gain may be protective against transient neonatal hyperinsulinism.

Clinical Diversity in Focal Congenital Hyperinsulinism in Infancy Correlates With Histological Heterogeneity of Islet Cell Lesions

Background: Congenital Hyperinsulinism (CHI) is an important cause of severe and persistent hypoglycaemia in infancy and childhood. The focal form (CHI-F) of CHI can be potentially cured by pancreatic lesionectomy. While diagnostic characteristics of CHI-F pancreatic histopathology are well-recognized, correlation with clinical phenotype has not been established. Aims: We aimed to correlate the diversity in clinical profiles of patients with islet cell organization in CHI-F pancreatic tissue. Methods: Clinical datasets were obtained from 25 patients with CHI-F due to ABCC8/KCNJ11 mutations. ¹⁸F-DOPA PET-CT was used to localize focal lesions prior to surgery. Immunohistochemistry was used to support protein expression studies. Results: In 28% (n = 7) of patient tissues focal lesions were amorphous and projected into adjoining normal pancreatic tissue without clear delineation from normal tissue. In these cases, severe hypoglycaemia was detected within, on average, 2.8 ± 0.8 (range 1-7) days following birth. By contrast, in 72% (n = 18) of tissues focal lesions were encapsulated within a defined matrix capsule. In this group, the onset of severe hypoglycaemia was generally delayed; on average 46.6 ± 14.3 (range 1-180) days following birth. For patients with encapsulated lesions and later-onset hypoglycaemia, we found that surgical procedures were curative and less complex. Conclusion: CHI-F is associated with heterogeneity in the organization of focal lesions, which correlates well with clinical presentation and surgical outcomes.

Congenital hyperinsulinism: diagnostic and management challenges in a developing country - case report

Management of congenital hyperinsulinemia of infancy (CHI) is challenging. A 4-month-old female infant with persistent hypoglycemia and elevated insulin levels was diagnosed with CHI. Gallium-68 DOTANOC positron emission tomography/computed tomography (PET/CT) scan (⁶⁸Ga-labeled [1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid]-1-NaI3-octreotide) demonstrated focal disease in the body of the pancreas. Genetic studies indicated paternal inheritance, making focal disease likely. She was started on diazoxide therapy with partial improvement in blood glucose levels. Due to a suboptimal response to diazoxide and the likelihood of focal disease amenable to surgery, a laparoscopic subtotal pancreatectomy with preservation of the head of the pancreas was performed. The biopsy demonstrated diffuse hyperplastic pancreatic islet cells on immunohistochemistry, indicative of diffuse rather than focal disease. Paternal inheritance is a recognized indicator of focal disease. Gallium-68 DOTANOC PET/CT scan is the only available imaging modality in South India as ¹⁸F-L-dihydroxyphenylalanine (DOPA) PET/CT scan is not available at present. A laparoscopic approach reduces the postoperative recovery time and morbidity in such patients. The absence of ¹⁸F-L-DOPA PET/CT scan and the limited supply of diazoxide makes the management of this complex condition more challenging in developing countries.

Congenital Hyperinsulinism

Congenital hyperinsulinism is a rare disorder that commonly presents in the immediate postnatal period as persistent hypoglycemia. The condition is frequently resistant to medical therapies, and the genetic mutations implicated in the disorder can be predictive of response to therapy. Evaluation of hypoglycemia in the illustrative case presented in this article led to genetic testing identifying recessive mutations in the potassium channel subunits of the beta-islet pancreatic cells. Potassium channel defects are often refractory to medical therapies, so near-total pancreatectomy is usually indicated; however, genetic mutations leading to metabolic dysregulation within the beta-islet pancreatic cells are usually responsive to medical therapy. Aggressive treatment of hypoglycemia in the setting of congenital hyperinsulinism is important to prevent long-term neurologic sequelae secondary to hypoglycemia-induced brain injury. [Pediatr Ann. 2017;46(11):e409-e414.].

Glycolate oxidase deficiency in a patient with congenital hyperinsulinism and unexplained hyperoxaluria

BACKGROUND

A baby girl was born at 39 weeks gestation to consanguineous Asian parents. From day 1 of life she had severe hypoglycaemia with an inappropriately elevated insulin concentration consistent with congenital hyperinsulinism (CHI), confirmed by the finding of a homozygous mutation in ABCC8 (encoding the sulfonylurea receptor 1).

CASE DIAGNOSIS/TREATMENT

Urine organic acid analysis showed an incidentally elevated excretion of glycolate. Whilst this was unlikely to contribute to the hypoglycaemia, hyperglycolic aciduria is a known feature of primary hyperoxaluria type 1 (PH1); therefore oxalate was also measured in urine and found to be elevated. Sequence analysis of the genes involved in PH1 and also the two other known forms of primary hyperoxaluria revealed no pathological variants. PH1 was definitively excluded by enzyme activity analysis on a liver biopsy, which confirmed normal glyoxylate aminotransferase (AGT) activity and positive AGT immunoreactivity. Glycolate oxidase (GO) deficiency was considered, and thus gene sequencing of HAO1, which encodes GO, was performed. A homozygous change (c.493G>T p.(Gly165Cys)) was found in exon 3 of HAO1, predicted to be deleterious to protein function. Further analysis of the liver biopsy demonstrated absent GO enzyme activity, confirming GO deficiency in this case.

CONCLUSIONS

The results lead to the conclusion that this baby has two unrelated autosomal recessive conditions, CHI and GO deficiency, and also hyperoxaluria of unknown aetiology. Deficiency of GO is a very rare disorder with only two previously published cases. It is considered to be an essentially benign inborn error of metabolism. The present case is unique in that GO deficiency is associated with persistent hyperoxaluria.

Late presentation of necrotizing enterocolitis associated with rotavirus infection in a term infant with hyperinsulinism on octreotide therapy: A case report

RATIONALE

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy that can cause permanent brain damage. Consequently, optimal management is extremely important. Current pharmacologic and surgical treatment were available that included diazoxide and octreotides.

PATIENT CONCERNS

A 4 month old Saudi male patient diagnosed at our hospital as CHI, treated with near total pancreatectomy and octreotide therapy of 30 mcg/kg/day presented with severe abdominal distension, vomiting and bloody diarrhea.

DIAGNOSES

The patient was diagnosed as necrotising enterocolitis (NEC) associated with Rota virus infection which played together with octeriotides as risk factors for NEC.

INTERVENTIONS

Radiological investigations and multidisciplinary team management with endocrinologist, neonatologist, pediatric surgeon, and gastroenterologist.

OUTCOMES

Resolution of NEC with conservative medical management and was discharged after 1 month of hospital stay with follow up with all concerned sub specialties.

LESSONS

NEC can develop in patients treated with octreotides especially when associated with another risk factor such as rotavirus infection.

Atypical Forms of Congenital Hyperinsulinism in Infancy Are Associated With Mosaic Patterns of Immature Islet Cells

OBJECTIVES

We aimed to characterize mosaic populations of pancreatic islet cells from patients with atypical congenital hyperinsulinism in infancy (CHI-A) and the expression profile of NKX2.2, a key transcription factor expressed in β-cells but suppressed in δ-cells in the mature pancreas.

PATIENTS/METHODS

Tissue was isolated from three patients with CHI-A following subtotal pancreatectomy. CHI-A was diagnosed on the basis of islet mosaicism and the absence of histopathological hallmarks of focal and diffuse CHI (CHI-D). Immunohistochemistry was used to identify and quantify the proportions of insulin-secreting β-cells and somatostatin-secreting δ-cells in atypical islets, and results were compared with CHI-D (n = 3) and age-matched control tissues (n = 3).

RESULTS

In CHI-A tissue, islets had a heterogeneous profile. In resting/quiescent islets, identified by a condensed cytoplasm and nuclear crowding, β-cells were reduced to <50% of the total cell numbers in n = 65/70 islets, whereas δ-cell numbers were increased with 85% of islets (n = 49/57) containing >20% δ-cells. In comparison, all islets in control tissue (n = 72) and 99% of CHI-D islets (n = 72) were composed of >50% β-cells, and >20% δ-cells were found only in 12% of CHI-D (n = 8/66) and 5% of control islets (n = 3/60). Active islets in CHI-A tissue contained proportions of β-cells and δ-cells similar to those of control and CHI-D islets. Finally, when compared with active islets, quiescent islets had a twofold higher prevalence of somatostatin/NKX2.2+ coexpressed cells.

CONCLUSIONS

Marked increases in NKX2.2 expression combined with increased numbers of δ-cells strongly imply that an immature δ-cell profile contributed to the pathobiology of CHI-A.

Development of Pulmonary Hypertension During Treatment with Diazoxide: A Case Series and Literature Review

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy. The mainstay of medical management for CHI is diazoxide. Diazoxide inhibits insulin release from the pancreas, but also causes smooth muscle relaxation and fluid retention so it is typically given with chlorothiazide. In July 2015, the FDA issued a drug safety communication warning that pulmonary hypertension (PH) had been reported in 11 infants being treated with diazoxide and that the PH resolved with withdrawal of diazoxide. All three of the cases in our hospital were admitted to the neonatal intensive care unit (NICU) for hypoglycemia. All patients received thorough radiologic and laboratory evaluations related to their diagnosis of CHI. All initially improved when diazoxide was initiated. Case 1 and case 3 were discharged from the NICU on diazoxide and chlorothiazide. Case 2 developed pulmonary hypertension while still in the NICU days after an increase in diazoxide dosing. Case 1 presented to the emergency room in respiratory distress shortly after discharge from the NICU with evidence of PH and heart failure. Case 3 presented to the emergency room after 2 weeks at home due to a home blood glucose reading that was low and developed PH and heart failure while an inpatient. Discontinuation of diazoxide led to resolution of all three patients' PH within approximately one week. The experience of our hospital indicates that pulmonary hypertension may be more common than previously thought in infants taking diazoxide. It is unclear if these symptoms develop slowly over time or if there is some other, as yet undescribed, trigger for the pulmonary hypertension. Our hospital's experience adds to the body of evidence and suggests these infants may benefit from more surveillance with echocardiography.

Clinical practice guidelines for congenital hyperinsulinism

Congenital hyperinsulinism is a rare condition, and following recent advances in diagnosis and treatment, it was considered necessary to formulate evidence-based clinical practice guidelines reflecting the most recent progress, to guide the practice of neonatologists, pediatric endocrinologists, general pediatricians, and pediatric surgeons. These guidelines cover a range of aspects, including general features of congenital hyperinsulinism, diagnostic criteria and tools for diagnosis, first- and second-line medical treatment, criteria for and details of surgical treatment, and future perspectives. These guidelines were generated as a collaborative effort between The Japanese Society for Pediatric Endocrinology and The Japanese Society of Pediatric Surgeons, and followed the official procedures of guideline generation to identify important clinical questions, perform a systematic literature review (April 2016), assess the evidence level of each paper, formulate the guidelines, and obtain public comments.

Modeling Congenital Hyperinsulinism with ABCC8-Deficient Human Embryonic Stem Cells Generated by CRISPR/Cas9

Congenital hyperinsulinism (CHI) is a rare genetic disorder characterized by excess insulin secretion, which results in hypoglycemia. Mutation of sulfonylurea receptor 1 (SUR1), encoded by the ABCC8 gene, is the main cause of CHI. Here, we captured the phenotype of excess insulin secretion through pancreatic differentiation of ABCC8-deficient stem cells generated by the CRISPR/Cas9 system. ABCC8-deficient insulin-producing cells secreted higher insulin than their wild-type counterparts, and the excess insulin secretion was rescued by nifedipine, octreotide and nicorandil. Further, we tested the role of SUR1 in response to different potassium levels and found that dysfunction of SUR1 decreased the insulin secretion rate in low and high potassium environments. Hence, pancreatic differentiation of ABCC8-deficient cells recapitulated the CHI disease phenotype in vitro, which represents an attractive model to further elucidate the function of SUR1 and to develop and screen for novel therapeutic drugs.

Treatment with long-acting lanreotide autogel in early infancy in patients with severe neonatal hyperinsulinism

BACKGROUND

Treatment of severe diffuse congenital hyperinsulinism (CHI) without sufficient response to diazoxide is complicated by the lack of approved drugs. Therefore, patients are often hospitalized long-term or have to undergo pancreatic surgery if episodes of severe hypoglycaemia cannot be prevented. A long-acting somatostatin analogue, octreotide, has been reported to be an effective treatment option that prevents severe hypoglycaemia in children with CHI, and its off-label use is common in CHI. However, octreotide requires continuous i.v. or s.c. infusion or multiple daily injections. Here, we report our experiences with the use of a monthly application of a long-acting somatostatin analogue, lanreotide autogel® (LAN-ATG), in early infancy.

RESULTS

The mean blood glucose concentration within 7 days before the first LAN-ATG administration were compared to 7 days after the first LAN-ATG administration and increased by 0.75 mmol/L (range 0.39-1.19 mmol/L). In the following weeks intravenous glucose infusions, octreotide, and glucagon treatment could be successfully stopped in all patients 3-20 days after the first LAN-ATG injection without substantial worsening of the hypoglycaemia rate. Increased carbohydrate requirements could be normalized with an average reduction in the carbohydrate-intake of 7 g/kg body weight/d (range 1.75-12.8 g/kg body weight/d). Over a total of 52 treatment months, no serious adverse effects occurred.

CONCLUSION

Long-term LAN-ATG treatment improved blood glucose concentrations, lowered the frequency of hypoglycaemia or allowed for normalization of oral carbohydrate intake in infants with CHI younger than 6 months of age. No severe side effects were observed. LAN-ATG might be an alternative treatment option in infants with severe CHI who lack risk factors for necrotizing enterocolitis and are not responding to current treatment regimens as an alternative to surgery after careful individual evaluation.

Clinical presentation and treatment response to diazoxide in two siblings with congenital hyperinsulinism as a result of a novel compound heterozygous ABCC8 missense mutation

BACKGROUND

Congenital hyperinsulinism (CHI) can present with considerable clinical heterogeneity which may be due to differences in the underlying genetic etiology. We present two siblings with hyperinsulinaemic hypoglycaemia (HH) and marked clinical heterogeneity caused by compound heterozygosity for the same two novel ABCC8 mutations.

CASE PRESENTATION

The index patient is a 3-year-old boy with hypoglycaemic episodes presenting on the first day of life. HH was diagnosed and treatment with intravenous glucose and diazoxide was initiated. Currently he has normal physical and neurological development, with occasional hypoglycaemic episodes detected following continuous fasting on treatment with diazoxide. The first-born 8-year-old sibling experienced severe postnatal hypoglycaemia, generalised seizures and severe brain damage despite diazoxide treatment. The latter was stopped at 6-months of age with no further registered hypoglycaemia. Genetic testing showed that both children were compound heterozygotes for two novel ABCC8 missense mutations p.I60N (c.179T>A) and p.G1555V (c.4664G>T).

CONCLUSIONS

These ABCC8 missense mutations warrant further studies mainly because of the variable clinical presentation and treatment response.

A Novel Homozygous Mutation in the KCNJ11 Gene of a Neonate with Congenital Hyperinsulinism and Successful Management with Sirolimus

Congenital hyperinsulinism (CHI) is the most common cause of neonatal persistent hypoglycemia caused by mutations in nine known genes. Early diagnosis and treatment are important to prevent brain injury. The clinical presentation and response to pharmacological therapy may vary depending on the underlying pathology. Genetic analysis is important in the diagnosis, treatment, patient follow-up, and prediction of recurrence risk within families. Our patient had severe hypoglycemia and seizure following birth. His diagnostic evaluations including genetic testing confirmed CHI. He was treated with a high-glucose infusion, high-dose diazoxide, nifedipine, and glucagon infusion. A novel homozygous mutation (p.F315I) in the KCNJ11 gene, leading to diazoxide-unresponsive CHI, was identified. Both parents were heterozygous for this mutation. Our patient's clinical course was complicated by severe refractory hypoglycemia; he was successfully managed with sirolimus and surgical intervention was not required. Diazoxide, nifedipine, and glucagon were discontinued gradually following sirolimus therapy. The patient was discharged at 2 months of age on low-dose octreotide and sirolimus. His outpatient clinical follow-up continues with no episodes of hypoglycemia. We present a novel homozygous p.F315I mutation in the KCNJ11 gene leading to diazoxide-unresponsive CHI in a neonate. This case illustrates the challenges associated with the diagnosis and management of CHI, as well as the successful therapy with sirolimus.

A novel mutation of ABCC8 gene in a patient with diazoxide-unresponsive congenital hyperinsulinism

Congenital hyperinsulinism (CHI) is a rare condition that can cause irreversible brain damage during the neonatal period owing to the associated hypoglycemia. Hypoglycemia in CHI occurs secondary to the dysregulation of insulin secretion. CHI has been established as a genetic disorder of islet-cell hyperplasia, associated with a mutation of the ABCC8 or KCNJ11 genes, which encode the sulfonylurea receptor 1 and the inward rectifying potassium channel (Kir6.2) subunit of the ATP-sensitive potassium channel, respectively. We report the case of a female newborn infant who presented with repetitive seizures and episodes of apnea after birth, because of hypoglycemia. Investigations revealed hypoglycemia with hyperinsulinemia, but no ketone bodies, and a low level of free fatty acids. High dose glucose infusion, enteral feeding, and medications could not maintain the patient's serum glucose level. Genetic testing revealed a new variation of ABCC8 mutation. Therefore, we report this case of CHI caused by a novel mutation of ABCC8 in a half-Korean newborn infant with diazoxide-unresponsive hyperinsulinemic hypoglycemia.

Hyperinsulinemic hypoglycemia in Beckwith-Wiedemann, Sotos, and Kabuki syndromes: A nationwide survey in Japan

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth syndrome that is occasionally associated with hyperinsulinemic hypoglycemia (HH) in the neonatal period. Sotos syndrome (SS) and Kabuki syndrome (KS) are other malformation syndromes that may be complicated with HH, however, the detailed clinical characteristics of HH accompanied with these syndromes remain unclear. We herein conducted a nationwide questionnaire survey in Japan. We sent a primary questionnaire concerning the clinical experience for these syndromes to 347 perinatal care institutions. As a result, 222 departments or hospitals returned the questionnaires and the total numbers of BWS, SS, and KS patients were 113, 88, and 51, respectively. We sent a secondary questionnaire to 31 institutions where patients with these syndromes presented with HH during infancy. The secondary questionnaires were returned from the institutions and the numbers of patients were 16 for BWS, 9 for SS, and 3 for KS, respectively. Then, we compared the clinical characteristics of infants suffering from transient HH with and without these dysmorphic syndromes. As a result, BWS, SS, and KS patients showed significantly larger body size, lower Apgar scores, higher insulin levels at HH, and shorter durations of HH than non-dysmorphic infants with transient HH. We propose that a careful observation for the signs of HH, even if not specific to the syndromes, is important for the diagnosis of patients with BWS, SS, and KS in the postnatal period. © 2016 Wiley Periodicals, Inc.

Glucokinase mutation-a rare cause of recurrent hypoglycemia in adults: a case report and literature review

Background

Hypoglycemia occurs frequently in patients both in the inpatient and outpatient settings. While most hypoglycemia unrelated to diabetes treatment results from excessive endogenous insulin action, rare cases involve functional and congenital mutations in glycolytic enzymes of insulin regulation.

Case

A 21-year-old obese woman presented to the emergency department with complaints of repeated episodes of lethargy, syncope, dizziness, and sweating. She was referred from an outside facility on suspicion of insulinoma, with severe hypoglycemia unresponsive to repeated dextrose infusions. Her plasma glucose was 20 mg/dl at presentation, 44 mg/dl on arrival at our facility, and remained low in spite of multiple dextrose infusions. The patient had been treated for persistent hyperinsulinemic hypoglycemia of infancy at our neonatal facility and 4 years ago was diagnosed as having an activating glucokinase (GCK) mutation. She was then treated with octreotide and diazoxide with improvement in symptoms and blood glucose levels.

Conclusion

Improved diagnostication and management of uncommon genetic mutations as typified in this patient with an activating mutation of the GCK gene has expanded the spectrum of disease in adult medicine. This calls for improved patient information dissemination across different levels and aspects of the health care delivery system to ensure cost-effective and timely health care.

Experience of Octreotide Therapy for Hyperinsulinemic Hypoglycemia in Neonates Born Small for Gestational Age: A Case Series

AIMS

Hyperinsulinemic hypoglycemia (HH) is common in small-for-gestational-age (SGA) neonates. Diazoxide is often used as the first-line medication for HH in SGA neonates. Unfortunately, diazoxide is not authorized in China. We examined the effectiveness of octreotide as an alternative therapy to treat HH in SGA neonates. There is limited data on the use of octreotide in HH of SGA neonates.

METHODS

Seven SGA neonates with HH who were admitted to the Department of Neonatology at the Third Affiliated Hospital of Sun Yat-sen University between January 2013 and December 2014 received octreotide at an initial dose of 5 μg/kg/day through subcutaneous injection at 8-hour intervals. Depending on the glycemic control, the dose of octreotide was increased in increments of 2-5 μg/kg/day every 3-5 days to the maximum dose of 30 μg/kg/day.

RESULTS

The age of neonates with HH diagnosis ranged from 1 to 4 days. The maximum dose of octreotide ranged from 8 to 18 μg/kg/day. The duration of octreotide therapy ranged from 9 to 45 days. All patients had a clear glycemic response to octreotide, and no major adverse events were observed during the treatment.

CONCLUSIONS

Octreotide may be a useful alternative therapy in HH of SGA neonates when diazoxide is unavailable.

Successful treatment of a newborn with congenital hyperinsulinism having a novel heterozygous mutation in the ABCC8 gene using subtotal pancreatectomy

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in newborns and infants. CHI is characterized by unregulated secretion of insulin from pancreatic β: cells. Here, we reported the case of a large-for-gestational-age, full-term newborn that suffered from CHI and developed severe and persistent hypoglycemia at an early stage of life. The infant was nearly unresponsive to medical treatment, which included continuous intravenous glucagon infusion, oral diazoxide, and nifedipine. After medical treatment had failed, an 18-fluoro L-3,4-dihydroxyphenylalanine positron emission tomography scan of the patient showed a focal lesion at the neck of the pancreas. The patient received subtotal pancreatectomy, and shortly after the procedure, the patient's blood sugar returned to the normal range. The patient was confirmed to have a novel heterozygous mutation at position c.2475+1G>A of the ABCC8 gene. This is the first report of a focal form of CHI in a patient in Taiwan, which had preoperatively been confirmed using 18-fluoro L-3,4-dihydroxyphenylalanine positron emission tomography.

Hyperinsulinemic Hypoglycemia in Infancy: Current Concepts in Diagnosis and Management

PURPOSE

Molecular basis of various forms of hyperinsulinemic hypoglycemia, involving defects in key genes regulating insulin secretion, are being increasingly reported. However, the management of medically unresponsive hyperinsulinism still remains a challenge as current facilities for genetic diagnosis and appropriate imaging are limited only to very few centers in the world. We aim to provide an overview of spectrum of clinical presentation, diagnosis and management of hyperinsulinism.

METHODS

We searched the Cochrane library, MEDLINE and EMBASE databases, and reference lists of identified studies.

CONCLUSION

Analysis of blood samples, collected at the time of hypoglycemic episodes, for intermediary metabolites and hormones is critical for diagnosis and treatment. Increased awareness among clinicians about infants at-risk of hypoglycemia, and recent advances in genetic diagnosis have made remarkable contribution to the diagnosis and management of hyperinsulinism. Newer drugs like lanreotide a long acting somatostatin analogue and sirolimus (mammalian target of rapamycin (mTOR) inhibitor) appears promising as patients with diffuse disease can be treated successfully without subtotal pancreatectomy, minimizing the long-term sequelae of diabetes and pancreatic insufficiency. Newer insights in understanding the molecular and histological basis and improvements in imaging and surgical techniques will modify the approach to patients with congenital hyperinsulinism.

Enhanced Islet Cell Nucleomegaly Defines Diffuse Congenital Hyperinsulinism in Infancy but Not Other Forms of the Disease

OBJECTIVES

To quantify islet cell nucleomegaly in controls and tissues obtained from patients with congenital hyperinsulinism in infancy (CHI) and to examine the association of nucleomegaly with proliferation.

METHODS

High-content analysis of histologic sections and serial block-face scanning electron microscopy were used to quantify nucleomegaly.

RESULTS

Enlarged islet cell nuclear areas were 4.3-fold larger than unaffected nuclei, and the mean nuclear volume increased to approximately threefold. Nucleomegaly was a normal feature of pediatric islets and detected in the normal regions of the pancreas from patients with focal CHI. The incidence of nucleomegaly was highest in diffuse CHI (CHI-D), with more than 45% of islets containing two or more affected cells. While in CHI-D nucleomegaly was negatively correlated with cell proliferation, in all other cases, there was a positive correlation.

CONCLUSIONS

Increased incidence of nucleomegaly is pathognomonic for CHI-D, but these cells are nonproliferative, suggesting a novel role in the pathobiology of this condition.

Monogenic Diabetes: What It Teaches Us on the Common Forms of Type 1 and Type 2 Diabetes

To date, more than 30 genes have been linked to monogenic diabetes. Candidate gene and genome-wide association studies have identified > 50 susceptibility loci for common type 1 diabetes (T1D) and approximately 100 susceptibility loci for type 2 diabetes (T2D). About 1-5% of all cases of diabetes result from single-gene mutations and are called monogenic diabetes. Here, we review the pathophysiological basis of the role of monogenic diabetes genes that have also been found to be associated with common T1D and/or T2D. Variants of approximately one-third of monogenic diabetes genes are associated with T2D, but not T1D. Two of the T2D-associated monogenic diabetes genes-potassium inward-rectifying channel, subfamily J, member 11 (KCNJ11), which controls glucose-stimulated insulin secretion in the β-cell; and peroxisome proliferator-activated receptor γ (PPARG), which impacts multiple tissue targets in relation to inflammation and insulin sensitivity-have been developed as major antidiabetic drug targets. Another monogenic diabetes gene, the preproinsulin gene (INS), is unique in that INS mutations can cause hyperinsulinemia, hyperproinsulinemia, neonatal diabetes mellitus, one type of maturity-onset diabetes of the young (MODY10), and autoantibody-negative T1D. Dominant heterozygous INS mutations are the second most common cause of permanent neonatal diabetes. Moreover, INS gene variants are strongly associated with common T1D (type 1a), but inconsistently with T2D. Variants of the monogenic diabetes gene Gli-similar 3 (GLIS3) are associated with both T1D and T2D. GLIS3 is a key transcription factor in insulin production and β-cell differentiation during embryonic development, which perturbation forms the basis of monogenic diabetes as well as its association with T1D. GLIS3 is also required for compensatory β-cell proliferation in adults; impairment of this function predisposes to T2D. Thus, monogenic forms of diabetes are invaluable "human models" that have contributed to our understanding of the pathophysiological basis of common T1D and T2D.

ABCC8 R1420H Loss-of-Function Variant in a Southwest American Indian Community: Association With Increased Birth Weight and Doubled Risk of Type 2 Diabetes

Missense variants in KCNJ11 and ABCC8, which encode the KIR6.2 and SUR1 subunits of the β-cell KATP channel, have previously been implicated in type 2 diabetes, neonatal diabetes, and hyperinsulinemic hypoglycemia of infancy (HHI). To determine whether variation in these genes affects risk for type 2 diabetes or increased birth weight as a consequence of fetal hyperinsulinemia in Pima Indians, missense and common noncoding variants were analyzed in individuals living in the Gila River Indian Community. A R1420H variant in SUR1 (ABCC8) was identified in 3.3% of the population (N = 7,710). R1420H carriers had higher mean birth weights and a twofold increased risk for type 2 diabetes with a 7-year earlier onset age despite being leaner than noncarriers. One individual homozygous for R1420H was identified; retrospective review of his medical records was consistent with HHI and a diagnosis of diabetes at age 3.5 years. In vitro studies showed that the R1420H substitution decreases KATP channel activity. Identification of this loss-of-function variant in ABCC8 with a carrier frequency of 3.3% affects clinical care as homozygous inheritance and potential HHI will occur in 1/3,600 births in this American Indian population.