Hyperinsulinism in infants and children

Sequential Dearomatization/Rearrangement of Quinazoline-Derived Azomethine Imines for the Synthesis of Nitrogen-Rich Three-Dimensional Cage-Like Molecules

A sequential dearomatization/rearrangement reaction between quinazoline-derived azomethine imines and crotonate sulfonium salts has been developed to provide a series of three-dimensional cage-like molecules. The reaction involves two dearomatizations, two cyclizations, and two C-C bond and three C-N bond formations in one step. The new transformation has a broad substrate scope, does not require any added reagents, and proceeds under room temperature in a short time. A mechanistic rationale for the sequential dearomatization/rearrangement is also presented. Furthermore, the synthetic compounds are evaluated for their glucose control effect. Compounds 3aa and 3aj were found to be hyperglycemic, which might be lead compounds for treating hypoglycemia.

Hypoglycemia in Children: Major Endocrine-Metabolic Causes and Novel Therapeutic Perspectives

Hypoglycemia is due to defects in the metabolic systems involved in the transition from the fed to the fasting state or in the hormone control of these systems. In children, hypoglycemia is considered a metabolic-endocrine emergency, because it may lead to brain injury, permanent neurological sequelae and, in rare cases, death. Symptoms are nonspecific, particularly in infants and young children. Diagnosis is based on laboratory investigations during a hypoglycemic event, but it may also require biochemical tests between episodes, dynamic endocrine tests and molecular genetics. This narrative review presents the age-related definitions of hypoglycemia, its pathophysiology and main causes, and discusses the current diagnostic and modern therapeutic approaches.

Congenital hyperinsulinism: localization of a focal lesion with 18F-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.

Natural history and neurodevelopmental outcomes in perinatal stress induced hyperinsulinism

OBJECTIVE

To describe perinatal stress induced hyperinsulinism (PSIHI), determine the prevalence of neurodevelopmental differences, and identify risk factors for poor developmental prognosis.

METHODS

Subjects with a history of hyperinsulinism (HI) and perinatal stress and in whom resolution of the HI was demonstrated were included. Medical record review, caregiver interview, and three validated developmental assessments were completed.

RESULTS

Of the 107 subjects (75% male), 36% were born between 32 and 37 weeks. Median age of hypoglycemia presentation was 0 days. Median age at HI diagnosis was 12 days (IQR 13.5). Median length of time for initiation of definitive treatment was 14 days (IQR 14).Caregiver interviews were completed for 53 of 79 eligible subjects. Developmental concerns were reported by 51%. Neurodevelopmental assessments were completed by caregivers of 37 of the 53 enrolled subjects. The proportion of subjects scoring >1 SD and >2 SD away from the mean in the direction of concern on the major composite scores was significantly greater than in the general population (40.5% vs. 15.8%, P ≤ 0.0001 and 18.9% vs. 2.2%, P ≤ 0.0001, respectively).Male sex, small for gestational age status (SGA), and treatment with continuous feeds were associated with assessment scores >1 SD from the mean (P < 0.05). SGA and preeclampsia were associated with assessment scores >2 SD from the mean (P < 0.05).

CONCLUSION

While the majority of infants presented with hypoglycemia in the first day of life, diagnosis and treatment occurred 12-14 days later. Children with PSIHI are at high risk of neurodevelopmental deficits and are more likely to perform below average on developmental assessment.

Congenital Hyperinsulinism International: A Community Focused on Improving the Lives of People Living With Congenital Hyperinsulinism

Congenital hyperinsulinism (HI) is a rare disease affecting newborns. HI causes severe hypoglycemia due to the overproduction of insulin. The signs and symptoms of hypoglycemia in HI babies is often not discovered until brain damage has already occurred. Prolonged hypoglycemia from HI can even lead to death. Disease management is often complex with a high burden on caregivers. Treatment options are extremely limited and often require long hospital stays to devise. Cascading from suboptimal treatments and diagnostic practices are a host of other problems and challenges that many with HI and their families experience including continued fear of hypoglycemia and feeding problems. The aim of this paper is (1) to describe the current challenges of living with HI including diagnosis and disease management told from the perspective of people who live with the condition (2), to provide family stories of life with HI, and (3) to share how a rare disease patient organization, Congenital Hyperinsulinism International (CHI) is working to improve the lives of HI patients and their families. CHI is a United States based nonprofit organization with a global focus. The paper communicates the programs the patient advocacy organization has put into place to support HI families through its virtual and in-person gatherings. The organization also helps individuals access diagnostics, medical experts, and treatments. CHI also raises awareness of HI to improve patient outcomes with information about HI and prolonged hypoglycemia in twenty-three languages. CHI drives innovation for new and better treatments by funding research pilot grants, conducting research through the HI Global Registry, and providing patient experience expertise to researchers developing new treatments. The organization is also the sponsor of the CHI Collaborative Research Network which brings medical and scientific experts together for the development of a patient-focused prioritized research agenda.

Novel Compound Heterozygous Variants of the ABCC8 Gene Warrant Identification of Pancreatic Histology in Infant with Diazoxide-unresponsive Congenital Hyperinsulinism

Congenital hyperinsulinism (CHI) is characterized by dysregulated insulin secretion, resulting in severe hypoglycemia. Mutations in the ABCC8 and KCNJ11 genes encoding KATP channels in beta cells of the pancreas are common among patients with CHI. Autosomal recessive CHI with diffuse involvement is the most common type of CHI among Saudi patients. It is relatively common for patients with autosomal recessive CHI to be medically unresponsive and undergo pancreatectomy. In this case report, we describe novel compound heterozygous variants in the ABCC8 gene in a Saudi infant that caused diazoxide-unresponsive CHI. The variants included a monoallelic paternally inherited variant that has been previously reported to cause a focal form of CHI and a maternally inherited variant of unknown significance (VUS). The severity of CHI in this patient was mild over the one-year follow-up period, with a near-optimal glycemic response on a low dose of octreotide. We suspected an atypical subtype of histological involvement in the patient. In this report, we highlight the phenotypic spectrum of novel compound heterozygous variants in a patient with CHI and consider that the report can help establish the pathogenicity of the VUS.

18F-6-Fluoro-l-Dopa PET/CT Imaging of Congenital Hyperinsulinism

Congenital hyperinsulinism is characterized by persistent hypoglycemia due to inappropriate excess secretion of insulin resulting in hyperinsulinemic hypoglycemia. The clinical course varies from mild to severe, with a significant risk for brain damage. Imaging plays a valuable role in the care of infants and children with severe hypoglycemia unresponsive to medical therapy. 18F-6-fluoro-l-dopa PET/CT is the method of choice for the detection and localization of a focal lesion of hyperinsulinism. Surgical resection of a focal lesion can lead to a cure with limited pancreatectomy. This article reviews the role of 18F-6-fluoro-l-dopa PET/CT in the management of this vulnerable population.

Congenital Hyperinsulinism Caused by Novel Homozygous KATP Channel Gene Variants May Be Linked to Unexplained Neonatal Deaths among Kurdish Consanguineous Families

INTRODUCTION

Neonatal hypoglycemia due to congenital hyperinsulinism (CHI) is a potentially life-threatening condition. Biallelic pathogenic variants in KATP channel subunit genes (ABCC8, KCNJ11), causing severe forms of CHI, are more prevalent in regions with a significant rate of consanguinity and may lead to unexplained neonatal deaths. We hypothesized that KATP channel gene variants are the cause of CHI in three unrelated children from consanguineous Kurdish families with histories of four unexplained neonatal deaths with convulsions.

CASES

(1) A girl presented on the 6th day of life with recurrent hypoglycemic convulsions (blood glucose 2.05 mmol/L, insulin 58 mIU/L, C-peptide 2,242 pmol/L). (2) A girl with severe developmental delay was diagnosed with CHI at 3 years of age (blood glucose 2.78 mmol/L, insulin 8.1 mIU/L, C-peptide 761 pmol/L) despite a history of recurrent hypoglycemia since neonatal age. (3) A girl presented at 3 weeks of age with convulsions and unconsciousness (blood glucose 2.5 mmol/L, insulin 14.6 mIU/L, C-peptide 523 pmol/L). Coding regions of the ABCC8 and KCNJ11 genes were tested by Sanger sequencing. Potential variants were evaluated using the American College of Medical Genetics standards. Three novel causative homozygous variants were found - p.Trp514Ter in the ABCC8 gene (Pt2), and p.Met1Val (Pt1) and p.Tyr26Ter (Pt3) in the KCNJ11 gene.

CONCLUSION

CHI caused by KATP channel variants was elucidated in three children, providing a highly probable retrospective diagnosis for their deceased siblings. Future lives can be saved by timely diagnosis of CHI when encountering a neonate with unexplained seizures or other signs of recurrent and/or persistent hypoglycemia.

Production and purification of ATP-sensitive potassium channel particles for cryo-electron microscopy

ATP-sensitive potassium (K_ATP) channels are multimeric protein complexes made of four inward rectifying potassium channel (Kir6.x) subunits and four ABC protein sulfonylurea receptor (SURx) subunits. Kir6.x subunits form the potassium ion conducting pore of the channel, and SURx functions to regulate Kir6.x. Kir6.x and SURx are uniquely dependent on each other for expression and function. In pancreatic β-cells, channels comprising SUR1 and Kir6.2 mediate glucose-stimulated insulin secretion and are the targets of antidiabetic sulfonylureas. Mutations in genes encoding SUR1 or Kir6.2 are linked to insulin secretion disorders, with loss- or gain-of-function mutations causing congenital hyperinsulinism or neonatal diabetes mellitus, respectively. Defects in the K_ATP channel in other tissues underlie human diseases of the cardiovascular and nervous systems. Key to understanding how channels are regulated by physiological and pharmacological ligands and how mutations disrupt channel assembly or gating to cause disease is the ability to observe structural changes associated with subunit interactions and ligand binding. While recent advances in the structural method of single-particle cryo-electron microscopy (cryoEM) offers direct visualization of channel structures, success of obtaining high-resolution structures is dependent on highly concentrated, homogeneous K_ATP channel particles. In this chapter, we describe a method for expressing K_ATP channels in mammalian cell culture, solubilizing the channel in detergent micelles and purifying K_ATP channels using an affinity tag to the SURx subunit for cryoEM structural studies.

Imprinted Genes Impact Upon Beta Cell Function in the Current (and Potentially Next) Generation

Beta cell failure lies at the centre of the aetiology and pathogenesis of type 2 diabetes and the epigenetic control of the expression of critical beta cell genes appears to play a major role in this decline. One such group of epigenetically-controlled genes, termed 'imprinted' genes, are characterised by transgenerational monoallelic expression due to differential allelic DNA methylation and play key functional roles within beta cells. Here, we review the evidence for this functional importance of imprinted genes in beta cells as well as their nutritional regulation by the diet and their altered methylation and/or expression in rodent models of diabetes and in type 2 diabetic islets. We also discuss imprinted genes in the context of the next generation, where dietary overnutrition in the parents can lead to their deregulation in the offspring, alongside beta cell dysfunction and defective glucose handling. Both the modulation of imprinted gene expression and the likelihood of developing type 2 diabetes in adulthood are susceptible to the impact of nutritional status in early life. Imprinted loci, therefore, represent an excellent opportunity with which to assess epigenomic changes in beta cells due to the diet in both the current and next generation.

Preclinical and Clinical Epigenetic-Based Reconsideration of Beckwith-Wiedemann Syndrome

Epigenetics has achieved a profound impact in the biomedical field, providing new experimental opportunities and innovative therapeutic strategies to face a plethora of diseases. In the rare diseases scenario, Beckwith-Wiedemann syndrome (BWS) is a pediatric pathological condition characterized by a complex molecular basis, showing alterations in the expression of different growth-regulating genes. The molecular origin of BWS is associated with impairments in the genomic imprinting of two domains at the 11p15.5 chromosomal region. The first domain contains three different regions: insulin growth like factor gene (IGF2), H19, and abnormally methylated DMR1 region. The second domain consists of cell proliferation and regulating-genes such as CDKN1C gene encoding for cyclin kinase inhibitor its role is to block cell proliferation. Although most cases are sporadic, about 5-10% of BWS patients have inheritance characteristics. In the 11p15.5 region, some of the patients have maternal chromosomal rearrangements while others have Uniparental Paternal Disomy UPD(11)pat. Defects in DNA methylation cause alteration of genes and the genomic structure equilibrium leading uncontrolled cell proliferation, which is a typical tumorigenesis event. Indeed, in BWS patients an increased childhood tumor predisposition is observed. Here, we summarize the latest knowledge on BWS and focus on the impact of epigenetic alterations to an increased cancer risk development and to metabolic disorders. Moreover, we highlight the correlation between assisted reproductive technologies and this rare disease. We also discuss intriguing aspects of BWS in twinning. Epigenetic therapies in clinical trials have already demonstrated effectiveness in oncological and non-oncological diseases. In this review, we propose a potential "epigenetic-based" approaches may unveil new therapeutic options for BWS patients. Although the complexity of the syndrome is high, patients can be able to lead a normal life but tumor predispositions might impair life expectancy. In this sense epigenetic therapies should have a supporting role in order to guarantee a good prognosis.

Inheritance of a paternal ABCC8 variant and maternal loss of heterozygosity at 11p15 retrospectively unmasks the etiology in a case of Congenital hyperinsulinism

Advances in genomics and 18F-DOPA PET-CT imaging have transformed the management of infants with Congenital Hyperinsulinism. Preoperative diagnosis of focal hyperinsulinism permits limited pancreatectomy with improved clinical outcomes while knowledge of the molecular etiology informs genetic counseling and provides a more accurate recurrence risk to families.

Risk Factors for Adverse Neurodevelopment in Transient or Persistent Congenital Hyperinsulinism

OBJECTIVE

Aim was to identify hypotheses why adverse neurodevelopment still occurs in children with transient or persistent hyperinsulinism despite improvements in long-term treatment options during the last decades.

MATERIAL AND METHODS

A retrospective review of 87 children with transient (n=37) or persistent congenital hyperinsulinism (CHI) (n=50) was conducted at the University Children's Hospital Duesseldorf, Germany. Possible risk factors for neurodevelopmental sequelae due to hypoglycemia were analyzed with a focus on the first days after onset of disease.

RESULTS

Median age at follow-up was 7 years (IQR 8). Adverse neurodevelopmental outcome was seen in 34.5% (n=30) of all CHI patients. Fifteen had mildly abnormal neurodevelopment and 15 had a severe hypoglycemic brain injury. In univariate analysis, mildly abnormal neurodevelopment was associated with the diagnosis of persistent CHI (odds ratio (OR) 8.3; p=0.004) and higher birth weight (mean difference 1049 g; p<0.001). Severe hypoglycemic brain injury was associated with the diagnosis of persistent CHI (OR 5.1; p=0.013), being born abroad (OR 18.3; p<0.001) or in a lower-level maternity hospital (OR 4.8; p=0.039), and of note history of hypoglycemic seizures (OR 13.0; p=<0.001), and a delay between first symptoms of hypoglycemia and first blood glucose measurement/initiation of treatment (OR 10.7; p<0.001). Children with severe hypoglycemic brain injury had lower recorded blood glucose (mean difference -8.34 mg/dl; p=0.022) and higher birth weight than children with normal development (mean difference 829 g; p=0.012). In multivariate binary logistic regression models, lowest blood glucose <20 mg/dl (OR 134.3; p=0.004), a delay between initial symptoms and first blood glucose measurement/initiation of treatment (OR 71.7; p=0.017) and hypoglycemic seizures (OR 12.9; p=0.008) were positively correlated with severe brain injury. Analysis showed that the odds for brain injury decreased by 15% (OR 0.85; p=0.035) if the blood glucose increased by one unit.

CONCLUSION

While some risk factors for adverse outcome in CHI are not influenceable, others like lowest recorded blood glucose values <20 mg/dl, hypoglycemic seizures, and insufficiently-or even untreated hypoglycemia can be avoided. Future guidelines for management of neonatal hypoglycemia should address this by ensuring early identification and immediate treatment with appropriate escalation steps.

Neonatal cardiac hypertrophy: the role of hyperinsulinism-a review of literature

Hypertrophic cardiomyopathy (HCM) in neonates is a rare and heterogeneous disorder which is characterized by hypertrophy of heart with histological and functional disruption of the myocardial structure/composition. The prognosis of HCM depends on the underlying diagnosis. In this review, we emphasize the importance to consider hyperinsulinism in the differential diagnosis of HCM, as hyperinsulinism is widely associated with cardiac hypertrophy (CH) which cannot be distinguished from HCM on echocardiographic examination. We supply an overview of the incidence and treatment strategies of neonatal CH in a broad spectrum of hyperinsulinemic diseases. Reviewing the literature, we found that CH is reported in 13 to 44% of infants of diabetic mothers, in approximately 40% of infants with congenital hyperinsulinism, in 61% of infants with leprechaunism and in 48 to 61% of the patients with congenital generalized lipodystrophy. The correct diagnosis is of importance since there is a large variation in prognoses and there are various strategies to treat CH in hyperinsulinemic diseases.Conclusion: The relationship between CH and hyperinsulism has implications for clinical practice as it might help to establish the correct diagnosis in neonates with cardiac hypertrophy which has both prognostic and therapeutic consequences. In addition, CH should be recognized as a potential comorbidity which might necessitate treatment in all neonates with known hyperinsulinism.What is Known:• Hyperinsulinism is currently not acknowledged as a cause of hypertrophic cardiomyopathy (HCM) in textbooks and recent Pediatric Cardiomyopathy Registry publications.What is New:• This article presents an overview of the literature of hyperinsulinism in neonates and infants showing that hyperinsulinism is associated with cardiac hypertrophy (CH) in a broad range of hyperinsulinemic diseases.• As CH cannot be distinguished from HCM on echocardiographic examination, we emphasize the importance to consider hyperinsulinism in the differential diagnosis of HCM/CH as establishing the correct diagnosis has both prognostic and therapeutic consequences.

Allosteric discrimination at the NADH/ADP regulatory site of glutamate dehydrogenase

Glutamate dehydrogenase (GDH) is a target for treating insulin-related disorders, such as hyperinsulinism hyperammonemia syndrome. Modeling native ligand binding has shown promise in designing GDH inhibitors and activators. Our computational investigation of the nicotinamide adenine diphosphate hydride (NADH)/adenosine diphosphate (ADP) site presented in this paper provides insight into the opposite allosteric effects induced at a single site of binding inhibitor NADH versus activator ADP to GDH. The computed binding free-energy difference between NADH and ADP using thermodynamic integration is -0.3 kcal/mol, which is within the -0.275 and -1.7 kcal/mol experimental binding free-energy difference range. Our simulations show an interesting model of ADP with dissimilar binding conformations at each NADH/ADP site in the GDH trimer, which explains the poorly understood strong binding but weak activation shown in experimental studies. In contrast, NADH showed similar inhibitory binding conformations at each NADH/ADP site. The structural analysis of the important residues in the NADH/ADP binding site presented in this paper may provide potential targets for mutation studies for allosteric drug design.

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.

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.

Hyperinsulinism-hyperammonemia Syndrome in an Infant with Seizures

Hyperinsulinism-hyperammonemia syndrome (HI/HA) is the second most common form of persistent hyperinsulinemic hypoglycemia of infancy (PHHI). The main clinical characteristics of HI/HA syndrome are repeated episodes of symptomatic hypoglycemia, but not usually severe. Consequently, children with HI/HA syndrome are frequently not recognized in the first months of life. An 8-month-old boy was admitted to a hospital due to hypoglycemia seizures. He also had asymptomatic hyperammonemia with no signs of lethargy or headaches. Genetic testing revealed autosomal dominant syndrome, a mutation in the GLUD1 gene (p.Arg274Cys). The boy started treatment with diazoxide. Subsequent growth and neurological development were normal. Hypoglycemic symptoms in HI/HA syndrome may vary from being non specific to severe. As hypoglycemia could lead to brain injury and impairment of neurological development, timely diagnosis and management are essential. If transient hypoglycemia is ruled out, metabolic disorders must be taken into account.

Congenital hyperinsulinism as the presenting feature of Kabuki syndrome: clinical and molecular characterization of 9 affected individuals

PURPOSE

Describe the clinical and molecular findings of patients with Kabuki syndrome (KS) who present with hypoglycemia due to congenital hyperinsulinism (HI), and assess the incidence of KS in patients with HI.

METHODS

We documented the clinical features and molecular diagnoses of 9 infants with persistent HI and KS via a combination of sequencing and copy-number profiling methodologies. Subsequently, we retrospectively evaluated 100 infants with HI lacking a genetic diagnosis, for causative variants in KS genes.

RESULTS

Molecular diagnoses of KS were established by identification of pathogenic variants in KMT2D (n = 5) and KDM6A (n = 4). Among the 100 infants with HI of unknown genetic etiology, a KS diagnosis was uncovered in one patient.

CONCLUSIONS

The incidence of HI among patients with KS may be higher than previously reported, and KS may account for as much as 1% of patients diagnosed with HI. As the recognition of dysmorphic features associated with KS is challenging in the neonatal period, we propose KS should be considered in the differential diagnosis of HI. Since HI in patients with KS is well managed medically, a timely recognition of hyperinsulinemic episodes will improve outcomes, and prevent aggravation of the preexisting mild to moderate intellectual disability in KS.

Whole-exome sequencing for mutation detection in pediatric disorders of insulin secretion: Maturity onset diabetes of the young and congenital hyperinsulinism

BACKGROUND

To assess the utility of whole-exome sequencing (WES) for mutation detection in maturity-onset diabetes of the young (MODY) and congenital hyperinsulinism (CHI). MODY and CHI are the two commonest monogenic disorders of glucose-regulated insulin secretion in childhood, with 13 causative genes known for MODY and 10 causative genes identified for CHI. The large number of potential genes makes comprehensive screening using traditional methods expensive and time-consuming.

METHODS

Ten subjects with MODY and five with CHI with known mutations underwent WES using two different exome capture kits (Nimblegen SeqCap EZ Human v3.0 Exome Enrichment Kit, Nextera Rapid Capture Exome Kit). Analysis was blinded to previously identified mutations, and included assessment for large deletions. The target capture of five exome capture technologies was also analyzed using sequencing data from >2800 unrelated samples.

RESULTS

Four of five MODY mutations were identified using Nimblegen (including a large deletion in HNF1B). Although targeted, one mutation (in INS) had insufficient coverage for detection. Eleven of eleven mutations (six MODY, five CHI) were identified using Nextera Rapid (including the previously missed mutation). On reconciliation, all mutations concorded with previous data and no additional variants in MODY genes were detected. There were marked differences in the performance of the capture technologies.

CONCLUSIONS

WES can be useful for screening for MODY/CHI mutations, detecting both point mutations and large deletions. However, capture technologies require careful selection.

Congenital hyperinsulinism in Chinese patients: 5-yr treatment outcome of 95 clinical cases with genetic analysis of 55 cases

AIM

The aim of this study is to investigate the clinical features, therapeutic outcomes, and genetic mutations of congenital hyperinsulinism (CHI) in Chinese patients.

METHODS

The clinical features and therapeutic outcomes of 95 CHI cases were recorded, and genetic analyses were conducted to identify mutations in ABCC8 and KCNJ11 in 55 cases. Direct sequencing was carried out in 25 of the cases with ABCC8 and KCNJ11 mutations. Additionally, 16 samples with no mutations and the remaining 30 samples were sequenced using Ion Torrent platform.

RESULTS

Clinical misdiagnosis occurred in 36/95 (38%) of the cases. Most (82/95; 84%) of the patients were given diazoxide therapy combined with age-dependent frequent feeding, which was effective in 54/95 (66%) cases. The side effects of diazoxide included sodium and water retention, gastrointestinal reactions, polytrichia, and thrombocytopenia. Five patients were treated with octreotide for 1-4 months, of which 80% (4/5) showed a positive response. Non-surgical therapy was effective in 71/95 (75%) cases. Of the four children who received subtotal pancreatectomy, only one had a good outcome. The remission rate of hypoglycemia was 59% for children over 2-yr-old. The CHI-related gene mutation rate was 38% for potassium channel-related genes. Early onset of CHI and a lower diazoxide response rate were associated with potassium-ATP channel gene mutations.

CONCLUSION

Age-dependent frequent feeding is an acceptable therapy for CHI. Non-surgical therapy may be highly effective, in part, due to the low rate of potassium channel gene mutations. Surgical outcomes are unreliable without 18F-fluoro-L-DOPA positron emission tomography. Therefore, we do not recommend operation without definitive identification of the pathologic type.

Biomarkers of Insulin for the Diagnosis of Hyperinsulinemic Hypoglycemia in Infants and Children

OBJECTIVE

To evaluate thresholds of various biomarkers for defining excess insulin activity to recognize congenital hyperinsulinism.

STUDY DESIGN

This was a retrospective chart review of diagnostic fasting tests in children with ketotic hypoglycemia (n = 30) and genetically/pathology confirmed congenital hyperinsulinism (n = 28). Sensitivity and specificity for congenital hyperinsulinism were determined for plasma insulin, β-hydroxybutyrate, free fatty acids (FFA), C-peptide, insulin-like growth factor binding protein-1 (IGFBP-1), and the glycemic response to glucagon (through the glucagon stimulation test [GST]) at the time of hypoglycemia.

RESULTS

Only 23 of the 28 subjects with congenital hyperinsulinism had detectable insulin (median, 6.7 μIU/mL), and insulin was undetectable in all subjects with ketotic hypoglycemia. Compared with ketotic hypoglycemia, subjects with congenital hyperinsulinism had higher GST values (57 vs 13 mg/dL; ΔGST ≥30 mg/dL in 24 of 27 subjects with congenital hyperinsulinism vs 0 of 30 subjects with ketotic hypoglycemia) and C-peptide levels (1.55 vs 0.11 ng/mL), with lower levels of FFA (0.82 vs 2.51 mM) and IGFBP-1 (59.5 vs 634 ng/mL). At the time of hypoglycemia, the upper limits of β-hydroxybutyrate and FFA in subjects with congenital hyperinsulinism were higher than reported previously (β-hydroxybutyrate <1.8 mM and FFA <1.7 mM), providing the best sensitivity for congenital hyperinsulinism vs ketotic hypoglycemia. A C-peptide level ≥0.5 ng/mL was 89% sensitive and 100% specific, and an IGFBP-1 level ≤110 ng/mL was 85% sensitive and 96.6% specific.

CONCLUSION

Because low or undetectable insulin level during hypoglycemia does not exclude the diagnosis of hyperinsulinism, C-peptide and IGFBP-1 may inform the diagnosis of congenital hyperinsulinism. In this group of children with well-defined congenital hyperinsulinism, thresholds for "suppressed" β-hydroxybutyrate and FFA are higher than previously reported levels.

Minimally invasive surgical interventions in the treatment of primary persistent hyperinsulinemic hypoglycemia of infancy

Hyperinsulinemia, diagnosed by laboratory tests, should be diagnosed and treated as soon as possible to prevent fatal complications such as neurological damage. Patients who are resistant to medical therapy should be treated surgically. Minimally invasive surgery, a newly developed approach, is a good choice among surgical procedures to avoid unnecessary extensive pancreatectomy. Here, a 12-year-old boy is presented with diagnosis of hyperinsulinemic hypoglycemia who had recurrent attacks of hypoglycemia and seizures from infancy. Because of his unresponsiveness to medical therapy and his family's preference, he underwent laparoscopic pancreatectomy to reduce morbidity and hospital stay. Two years postsurgical follow-up revealed a normo-glycemic state.

Clinical and molecular data from 61 Brazilian cases of Congenital Hyperinsulinemic Hypoglycemia

OBJECTIVE

To study the clinical and molecular characteristics of a sample of Brazilian patients with Congenital Hyperinsulinemic Hypoglycemia (CHH).

METHODS

Electronic message was sent to members from Endocrinology Department- Brazilian Society of Pediatrics requesting clinical data for all cases of CHH. A whole blood sample from living patients was requested for DNA extraction followed by a search for mutations of the genes ABCC8, KCNJ11, GCK, GLUD1, HADH, SLC16A1 and HNF4A.

RESULTS

Of the 61 patients evaluated, 36 (59%) were boys, and only 16 (26%) were born by normal delivery. Gestational age ranged from 32 to 41 weeks (mean = 37 weeks and 6 days). Birth weight ranged from 1590 to 5250 g (mean = 3430 g). Macrossomia occurred in 14 cases (28%). Age at diagnosis ranged from 1 to 1080 days (mean = 75 days). DNA for molecular analysis was obtained from 53 of the 61 patients. Molecular changes in the ABCC8 gene were detected in 15 (28%) of these 53 cases, and mutations in the KCNJ11 gene were detected in 6 (11%). Mutations in the GLUD1 gene were detected in 9 cases (17%) of the total series. Mutations of the GCK gene in heterozygosis were detected in 3 cases. No mutations were detected in the sequencing of genes HADH, SLC16A1 and HNF4A.

CONCLUSION

The present study conducted in Brazil permitted the collaborative compilation of an important number of CHH cases and showed that the present clinical and molecular data are similar to those of published global series.

Congenital hyperinsulinism: exclusive human milk and breastfeeding

Congenital hyperinsulinism is a genetic condition causing dysregulation of insulin and results in persistent hypoglycemia. The most common types are sulfonylurea receptor (SUR1), potassium inward rectifying channel (Kir6.2), glutamate dehydrogenase (GDH), and glucokinase (GK), with SUR1 and Kir6.2 being the most prevalent. It is imperative that these infants undergo diagnostic testing, which includes genetic, neonatal fasting study to induce hypoglycemia, glucagon stimulation, and imaging. Once a diagnosis has been made, surgical intervention may be needed to help regulate blood glucose levels. During this diagnostic process and as the infant is undergoing treatment, there may be little concern for the mother's feeding plan. Because human milk is the preferred form of nutrition for all infants, these mothers should receive prenatal counseling regarding the initiation and maintenance of milk supply. Parenteral nutrition may be necessary to maintain blood glucose to support human milk administration and breastfeeding.

Pharmacological rescue of trafficking-impaired ATP-sensitive potassium channels

ATP-sensitive potassium (K_ATP) channels link cell metabolism to membrane excitability and are involved in a wide range of physiological processes including hormone secretion, control of vascular tone, and protection of cardiac and neuronal cells against ischemic injuries. In pancreatic β-cells, K_ATP channels play a key role in glucose-stimulated insulin secretion, and gain or loss of channel function results in neonatal diabetes or congenital hyperinsulinism, respectively. The β-cell K_ATP channel is formed by co-assembly of four Kir6.2 inwardly rectifying potassium channel subunits encoded by KCNJ11 and four sulfonylurea receptor 1 subunits encoded by ABCC8. Many mutations in ABCC8 or KCNJ11 cause loss of channel function, thus, congenital hyperinsulinism by hampering channel biogenesis and hence trafficking to the cell surface. The trafficking defects caused by a subset of these mutations can be corrected by sulfonylureas, K_ATP channel antagonists that have long been used to treat type 2 diabetes. More recently, carbamazepine, an anticonvulsant that is thought to target primarily voltage-gated sodium channels has been shown to correct K_ATP channel trafficking defects. This article reviews studies to date aimed at understanding the mechanisms by which mutations impair channel biogenesis and trafficking and the mechanisms by which pharmacological ligands overcome channel trafficking defects. Insight into channel structure-function relationships and therapeutic implications from these studies are discussed.

A novel mutation in ABCC8 gene in a newborn with congenital hyperinsulinism -a case report

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy. The genetic basis of CHI includes a variety of defects in key genes regulating insulin secretion. Mutations in at least seven genes are found in 50% of cases. The most common forms of medically unresponsive CHI, which requires a near-total pancreatectomy are associated with autosomal recessive mutations in the ABCC8 and KCNJ11 genes encoding the two subunits of the pancreatic β-cell ATP-sensitive potassium channel. We report a neonate with CHI and have a novel homozygous splicing mutation in the ABCC8 gene.

Hyperinsulinemic hypoglycemia: experience in a series of 17 cases

OBJECTIVE

Hyperinsulinemic hypoglycemia (HIH) is a genetically heterogeneous disorder with both familial and sporadic variants. Patients with HIH may present during the neonatal period, infancy, or childhood and may show transient, prolonged, and persistent features. In this study, we aimed to discuss our experience with HIH patients, based on a series of 17 patients.

METHODS

We retrospectively analyzed the clinical and laboratory characteristics at the time of diagnosis and during treatment and evaluated the neurodevelopmental outcomes during follow-up in 17 HIH patients, who presented or were referred to the Pediatric Endocrinology Clinic of Dr. Sami Ulus Training and Research Children's Hospital between 1998 and 2011. The patients (7 male, 10 female) were aged between the first day of life and 7 years - 10 were in their first week of life, 6 in their infancy, and 1 in childhood.

RESULTS

None of the mothers had gestational diabetes. Hypoglycemic seizure (76.5%) was the most common presenting symptom. Medical treatment failed in two patients, and was stopped in eight patients. Of two diazoxide-unresponsive patients, one underwent near-total pancreatectomy, but hypoglycaemic episodes continued after surgery. The parents of other patient refused surgery, the medical treatment was continued, nevertheless, severe motor and mental retardation developed. At follow-up, 23.5% of the patients were found to have mild or moderate psychomotor retardation, and 23.5% developed epilepsy. There was no marked difference in neurological results between cases with onset in the neonatal period or in infancy.

CONCLUSIONS

Clinical course and treatment response in HIH cases are very heterogeneous. Long-term careful monitoring is needed to detect and treat the complications.

Congenital hyperinsulinism: clinical and molecular analysis of a large Italian cohort

Congenital hyperinsulinism (CHI) is a genetic disorder characterized by profound hypoglycemia related to an inappropriate insulin secretion. It is a heterogeneous disease classified into two major subgroups: "channelopathies" due to defects in ATP-sensitive potassium channel, encoded by ABCC8 and KCNJ11 genes, and "metabolopathies" caused by mutation of several genes (GLUD1, GCK, HADH, SLC16A1, HNF4A and HNF1A) and involved in different metabolic pathways. To elucidate the genetic etiology of CHI in the Italian population, we conducted an extensive sequencing analysis of the CHI-related genes in a large cohort of 36 patients: Twenty-nine suffering from classic hyperinsulinism (HI) and seven from hyperinsulinism-hyperammonemia (HI/HA). Seventeen mutations have been found in fifteen HI patients and five mutations in five HI/HA patients. Our data confirm the major role of ATP-sensitive potassium channel in the pathogenesis of Italian cases (~70%) while the remaining percentage should be attributed to other. A better knowledge of molecular basis of CHI would lead to improve strategies for genetic screening and prenatal diagnosis. Moreover, genetic analysis might also help to distinguish the two histopathological forms of CHI, which would lead to a clear improvement in the treatment and in genetic counseling.

[Hyperinsulinemic hypoglycemia of the infancy: analysis of clinical data from a Brazilian sample]

OBJECTIVE

To review the presentation of hyperinsulinemic hypoglycemia of the infancy (HHI), its treatment and histology in Brazilian pediatric endocrinology sections.

MATERIALS AND METHOD

The protocol analyzed data of birth, laboratory results, treatment, surgery, and pancreas histology.

RESULTS

Twenty-five cases of HHI from six centers were analyzed: 15 male, 3/25 born by vaginal delivery. The average age at diagnosis was 10.3 days. Glucose and insulin levels in the critical sample showed an average of 24.7 mg/dL and 26.3 UI/dL. Intravenous infusion of the glucose was greater than 10 mg/kg/min in all cases (M:19,1). Diazoxide was used in 15/25 of the cases, octreotide in 10, glucocorticoid in 8, growth hormone in 3, nifedipine in 2 and glucagon in 1. Ten of the cases underwent pancreatectomy and histology results showed the diffuse form of disease.

CONCLUSION

This is the first critic review of a Brazilian sample with congenital HHI.

Pancreatic head resection preserving the main pancreatic duct for congenital hyperinsulinism of infancy

Surgical intervention for congenital hyperinsulinism with an unclear focal lesion in the pancreatic head sometimes require the resection of most of the pancreas head and pancreaticojejunotomy. This report presents the case of a patient that underwent pancreatic head resection preserving the main pancreatic duct to avoid pancreaticojejunostomy.

Pancreatic head resection and Roux-en-Y pancreaticojejunostomy for the treatment of the focal form of congenital hyperinsulinism

PURPOSE

To determine the outcome of patients who underwent pancreatic head resection and Roux-en-Y pancreaticojejunostomy to the remaining normal pancreatic body and tail for the treatment of a focal lesion in the pancreatic head causing congenital hyperinsulinism (HI).

METHODS

One hundred thirty-eight patients underwent pancreatic resection for focal HI between 1998 and 2010. Twenty-three patients in the group underwent pancreatic head resection and Roux-en-Y pancreaticojejunostomy.

RESULTS

There were 13 females and 10 males. Median age and weight at surgery were 8 weeks and 5.8 kg, respectively. Twenty-one patients had a near-total pancreatic head resection, and 2 patients had a pylorus-preserving Whipple procedure. The pancreaticojejunostomy anastomosis was performed with interrupted fine monofilament sutures such that the transected end of the pancreatic body was tucked within the end of the Roux-en-Y jejunal limb. Median hospital stay was 22 days. All patients were cured of HI.

CONCLUSION

We conclude that pancreatic head resection with Roux-en-Y pancreaticojejunostomy is a safe and effective procedure for the treatment of the HI patient with a large focal lesion in the pancreatic head that is not amenable to local resection alone.

Congenital hyperinsulinism: current trends in diagnosis and therapy

Congenital hyperinsulinism (HI) is an inappropriate insulin secretion by the pancreatic β-cells secondary to various genetic disorders. The incidence is estimated at 1/50, 000 live births, but it may be as high as 1/2, 500 in countries with substantial consanguinity. Recurrent episodes of hyperinsulinemic hypoglycemia may expose to high risk of brain damage. Hypoglycemias are diagnosed because of seizures, a faint, or any other neurological symptom, in the neonatal period or later, usually within the first two years of life. After the neonatal period, the patient can present the typical clinical features of a hypoglycemia: pallor, sweat and tachycardia. HI is a heterogeneous disorder with two main clinically indistinguishable histopathological lesions: diffuse and focal. Atypical lesions are under characterization. Recessive ABCC8 mutations (encoding SUR1, subunit of a potassium channel) and, more rarely, recessive KCNJ11 (encoding Kir6.2, subunit of the same potassium channel) mutations, are responsible for most severe diazoxide-unresponsive HI. Focal HI, also diazoxide-unresponsive, is due to the combination of a paternally-inherited ABCC8 or KCNJ11 mutation and a paternal isodisomy of the 11p15 region, which is specific to the islets cells within the focal lesion. Genetics and ¹⁸F-fluoro-L-DOPA positron emission tomography (PET) help to diagnose diffuse or focal forms of HI. Hypoglycemias must be rapidly and intensively treated to prevent severe and irreversible brain damage. This includes a glucose load and/or a glucagon injection, at the time of hypoglycemia, to correct it. Then a treatment to prevent the recurrence of hypoglycemia must be set, which may include frequent and glucose-enriched feeding, diazoxide and octreotide. When medical and dietary therapies are ineffective, or when a focal HI is suspected, surgical treatment is required. Focal HI may be definitively cured when the partial pancreatectomy removes the whole lesion. By contrast, the long-term outcome of diffuse HI after subtotal pancreatectomy is characterized by a high risk of diabetes, but the time of its onset is hardly predictable.

Perinatal endocrinology: common endocrine disorders in the sick and premature newborn

Endocrine disorders are common in infants in the neonatal ICU. They often are associated with prematurity, low birth weight or very low birth weight, and small size for gestational age. They also frequently occur in infants who are critically ill or stressed. This article describes the most common conditions and current knowledge regarding management.

3-hydroxyacyl-coenzyme a dehydrogenase deficiency: identification of a new mutation causing hyperinsulinemic hypoketotic hypoglycemia, altered organic acids and acylcarnitines concentrations

The human HADH gene encodes the short-chain-L-3-hydroxyacyl-CoA dehydrogenase, the enzyme which catalyzes the third step of the β-oxidation of the fatty acids in the mitochondrial matrix. Loss-of-function mutations in the HADH gene lead to short-chain-L-3-hydroxyacyl-CoA dehydrogenase deficiency, an autosomal recessive genetic defect of unknown prevalence with a wide spectrum of phenotypic variability. As in other metabolic diseases, the diagnostic relevance of the biochemical evaluations, plasma acylcarnitines, and urinary organic acids, are crucially dependent on the clinical conditions of the patient during specimen collection.This paper describes the eighth patient carrying a HADH gene mutation, a new homozygous deletion c.565delG leading to an early stop codon (p.V116Wfs124X), in an infant with hyperinsulininemic hypoglycemia, displaying abnormal patterns of plasma acylcarnitines and urinary organic acids. We conclude that, when the residual catalytic activity of the mutated enzyme is seriously reduced, the biochemical hallmarks of the disease, namely plasma 3-hydroxybutyrylcarnitine and urinary 3-hydroxyglutaric acid, are invariably present.

[Hypoglycemia hypersinsulinemic of infancy]

The hypoglycemia hyperinsulinemic of the infancy (HHI) is an emergency in the neonatal period. After a short period of fast the avid brain runs out of its main energy substrate. The authors overhaul the diagnosis of HH, not only in the neonatal period, but also in the late infant and in the adolescence. The aspects of the molecular alterations found in these cases, as well like the description of the main mutations are also approached.

Rare forms of congenital hyperinsulinism

Rare forms of congenital hyperinsulinism (CHI) are caused by mutations in GLUD1 (encoding glutamate dehydrogenase), GCK (encoding glucokinase), HADH (encoding for L-3-hydroxyacyl-CoA dehydrogenase), SLC16A1 (encoding the monocarboxylat transporter 1), HNF4A (encoding hepatocyte nuclear factor 4α) or UCP2 (encoding mitochondrial uncoupling protein 2). The clinical presentation is very heterogeneous in regards to age of onset, severity, and manner of symptoms, as well as the response to medical treatment. Special individual characteristics have to be accounted in diagnosis and treatment. Diazoxide is the first-line drug for the rare forms of CHI for long-term treatment but is not entirely effective in some of these rarer defects (GCK, MCT1). The use of diazoxide is often limited by side effects and the use of octreotide as second-line drug has to be considered. A near-total pancreatectomy is only reserved for patients with diffuse disease and resistance to medical treatment as a last resort. Patients with CHI should be managed by centers with a highly experienced team in diagnostic work-up and treatment of this disease.

Familial hyperinsulinism-hyperammonemia syndrome in a family with seizures: case report

Hyperinsulinism-hyperammonemia (HI/HA) syndrome is the second most frequent cause of congenital hyperinsulinism (CHI) and it is characterized by recurrent symptomatic hypoglycemia and persistent hyperammonemia. We describe the familial case of a 2-year-old child and her 32-year-old mother who, having suffered from tonic-clonic seizures since infancy, had both been diagnosed with epilepsy and treated with sodium valproate. Hypoglycemia was identified in the child in routine analysis. Six days after admission, a complete study of hypoglycemia showed test results compatible with hyperinsulinemic hypoglycemia and hyperammonemia. A mutation in the GDH gene (Arg269His) confirmed the diagnosis in both the mother and the child. An important peculiarity of this case is the diagnosis of a 32-year-old woman, previously diagnosed with epilepsy through her daughter's diagnosis at a Pediatric Endocrinology Department and subsequently treated ineffectively with sodium valproate. We conclude that, as hypoglycemia may be subtle, the diagnosis of HI/HA should be considered in children or adults with seizures/epilepsy and hyperammonemia, serum ammonia being a simple screening test for the disease.

Congenital hyperinsulinism

Congenital hyperinsulinism (CHI or HI) is a condition leading to recurrent hypoglycemia due to an inappropriate insulin secretion by the pancreatic islet beta cells. HI has two main characteristics: a high glucose requirement to correct hypoglycemia and a responsiveness of hypoglycemia to exogenous glucagon. HI is usually isolated but may be rarely part of a genetic syndrome (e.g. Beckwith-Wiedemann syndrome, Sotos syndrome etc.). The severity of HI is evaluated by the glucose administration rate required to maintain normal glycemia and the responsiveness to medical treatment. Neonatal onset HI is usually severe while late onset and syndromic HI are generally responsive to a medical treatment. Glycemia must be maintained within normal ranges to avoid brain damages, initially with glucose administration and glucagon infusion then, once the diagnosis is set, with specific HI treatment. Oral diazoxide is a first line treatment. In case of unresponsiveness to this treatment, somatostatin analogues and calcium antagonists may be added, and further investigations are required for the putative histological diagnosis: pancreatic (18)F-fluoro-L-DOPA PET-CT and molecular analysis. Indeed, focal forms consist of a focal adenomatous hyperplasia of islet cells, and will be cured after a partial pancreatectomy. Diffuse HI involves all the pancreatic beta cells of the whole pancreas. Diffuse HI resistant to medical treatment (octreotide, diazoxide, calcium antagonists and continuous feeding) may require subtotal pancreatectomy which post-operative outcome is unpredictable. The genetics of focal islet-cells hyperplasia associates a paternally inherited mutation of the ABCC8 or the KCNJ11 genes, with a loss of the maternal allele specifically in the hyperplasic islet cells. The genetics of diffuse isolated HI is heterogeneous and may be recessively inherited (ABCC8 and KCNJ11) or dominantly inherited (ABCC8, KCNJ11, GCK, GLUD1, SLC16A1, HNF4A and HADH). Syndromic HI are always diffuse form and the genetics depend on the syndrome. Except for HI due to potassium channel defect (ABCC8 and KCNJ11), most of these HI are sensitive to diazoxide. The main points sum up the management of HI: i) prevention of brain damages by normalizing glycemia and ii) screening for focal HI as they may be definitively cured after a limited pancreatectomy.

Persistent hyperinsulinemic hypoglycemia with left ventricular hypertrophy and dysrhythmia: a case report

Persistent hyperinsulinemic hypoglycemia in neonatal period is characterized by insulin hypersecretion. The major feature is severe hypoglycemia, generally unresponsive to routine medical treatment. Subtotal or total pancreatectomy is performed in unresponsive cases. In this case report, we present a newborn with persistent hypoglycemia unresponsive to medical treatment with dysrhythmic left ventricular hypertrophy. The insulin/C-peptide ratio was 58 as a confirmation of diagnosis. Since hypoglycemia persisted after the initial medical treatment, a subtotal pancreatectomy was performed followed by near-total pancreatectomy. A histologic examination revealed diffuse insulin islets. At the 70th post-natal day, death occurred due to heart failure and ventricular dysrhythmia. To our knowledge, severe dysrhythmia and left ventricular hypertrophy in persistent hyperinsulinemic hypoglycemia (PPH) is identified in the patient.

Perinatal endocrinology: common endocrine disorders in the sick and premature newborn

Endocrine disorders are common in infants in the neonatal ICU. They often are associated with prematurity, low birth weight or very low birth weight, and small size for gestational age. They also frequently occur in infants who are critically ill or stressed. This article describes the most common conditions and current knowledge regarding management.

Extremes of clinical and enzymatic phenotypes in children with hyperinsulinism caused by glucokinase activating mutations

OBJECTIVE

Heterozygous activating mutations of glucokinase have been reported to cause hypoglycemia attributable to hyperinsulinism in a limited number of families. We report three children with de novo glucokinase hyperinsulinism mutations who displayed a spectrum of clinical phenotypes corresponding to marked differences in enzyme kinetics.

RESEARCH DESIGN AND METHODS

Mutations were directly sequenced, and mutants were expressed as glutathionyl S-transferase-glucokinase fusion proteins. Kinetic analysis of the enzymes included determinations of stability, activity index, the response to glucokinase activator drug, and the effect of glucokinase regulatory protein.

RESULTS

Child 1 had an ins454A mutation, child 2 a W99L mutation, and child 3 an M197I mutation. Diazoxide treatment was effective in child 3 but ineffective in child 1 and only partially effective in child 2. Expression of the mutant glucokinase ins454A, W99L, and M197I enzymes revealed a continuum of high relative activity indexes in the three children (26, 8.9, and 3.1, respectively; wild type = 1.0). Allosteric responses to inhibition by glucokinase regulatory protein and activation by the drug RO0281675 were impaired by the ins454A but unaffected by the M197I mutation. Estimated thresholds for glucose-stimulated insulin release were more severely reduced by the ins454A than the M197I mutation and intermediate in the W99L mutation (1.1, 3.5, and 2.2 mmol/l, respectively; wild type = 5.0 mmol/l).

CONCLUSIONS

These results confirm the potency of glucokinase as the pancreatic beta-cell glucose sensor, and they demonstrate that responsiveness to diazoxide varies with genotype in glucokinase hyperinsulinism resulting in hypoglycemia, which can be more difficult to control than previously believed.

Laparoscopic vs open pancreatectomy for persistent hyperinsulinemic hypoglycemia of infancy

BACKGROUND

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is considered the most common cause of persistent neonatal hypoglycemia. The aim of this study is to compare laparoscopic pancreatectomy with open pancreatectomy for PHHI in one center regarding feasibility, safety, and effectiveness.

METHODS

A retrospective chart review was conducted for patients managed for PHHI with either laparoscopic or open pancreatectomy for the period from 2001 to 2007 at King Faisal Specialist Hospital and Research Center (Riyadh, Saudi Arabia). Demographic and clinical data were retrieved. Continuous variables were reported as means, and categorical variables were reported as proportions for each group. Means were compared using Student's t test, and proportions were compared using chi(2) test or Fisher's Exact test where appropriate. A P value less than .05 was considered statistically significant. The study proposal was approved by the Clinical Research Committee and the Research Ethics Committee at our institution.

RESULTS

Eighteen patients were managed with pancreatectomy for PHHI for that period: 10 laparoscopic and 8 open. The 2 groups were comparable regarding age and weight at surgery, sex, procedure duration, hospital stay postoperatively, need for reoperation, and development of diabetes mellitus and mental delay. Extent of resection was significantly higher in the open group (P value = .02), and the laparoscopic group was fed significantly earlier (P value = .001). The mean follow-up for the laparoscopic and the open groups were 20.4 months and 46 months, respectively (P value = .004).

CONCLUSIONS

Laparoscopic pancreatectomy for PHHI is safe and feasible. Our data suggest its effectiveness compared to the open approach.

Extended-release glipizide overdose presenting with delayed hypoglycemia and treated with subcutaneous octreotide

The onset of symptomatic hypoglycemia in children with ingestions of second-generation sulfonylureas has never been documented to be later than 21 hours post-ingestion. We report a case with the longest known interval, 45 hours, between ingestion of a sulfonylurea and the onset of hypoglycemia requiring medical intervention. The hypoglycemia was severe and required multiple dextrose boluses in addition to continuous dextrose infusion for 36 hours. This patient was also treated with multiple doses of subcutaneous octreotide because of persistent hypoglycemia despite the above management. This case represents the first report of subcutaneous octreotide used as a treatment for pediatric hypoglycemia secondary to sulfonylurea exposure.