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Ferreira G, Santander A, Cardozo R, Chavarría L, Domínguez L, Mujica N, Benítez M, Sastre S, Sobrevia L, Nicolson GL. Nutrigenomics of inward rectifier potassium channels. Biochim Biophys Acta Mol Basis Dis 2023:166803. [PMID: 37406972 DOI: 10.1016/j.bbadis.2023.166803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
Inwardly rectifying potassium (Kir) channels play a key role in maintaining the resting membrane potential and supporting potassium homeostasis. There are many variants of Kir channels, which are usually tetramers in which the main subunit has two trans-membrane helices attached to two N- and C-terminal cytoplasmic tails with a pore-forming loop in between that contains the selectivity filter. These channels have domains that are strongly modulated by molecules present in nutrients found in different diets, such as phosphoinositols, polyamines and Mg2+. These molecules can impact these channels directly or indirectly, either allosterically by modulation of enzymes or via the regulation of channel expression. A particular type of these channels is coupled to cell metabolism and inhibited by ATP (KATP channels, essential for insulin release and for the pathogenesis of metabolic diseases like diabetes mellitus). Genomic changes in Kir channels have a significant impact on metabolism, such as conditioning the nutrients and electrolytes that an individual can take. Thus, the nutrigenomics of ion channels is an important emerging field in which we are attempting to understand how nutrients and diets can affect the activity and expression of ion channels and how genomic changes in such channels may be the basis for pathological conditions that limit nutrition and electrolyte intake. In this contribution we briefly review Kir channels, discuss their nutrigenomics, characterize how different components in the diet affect their function and expression, and suggest how their genomic changes lead to pathological phenotypes that affect diet and electrolyte intake.
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Affiliation(s)
- Gonzalo Ferreira
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay.
| | - Axel Santander
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Romina Cardozo
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Luisina Chavarría
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Lucía Domínguez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Nicolás Mujica
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Milagros Benítez
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay
| | - Santiago Sastre
- Laboratory of Ion Channels, Biological Membranes and Cell Signaling, Dept. of Biophysics, Facultad de Medicina, CP 11800, Universidad de la Republica, Montevideo, Uruguay; Centro de Investigaciones Biomédicas (CEINBIO), Universidad de la República, Montevideo CP 11800, Uruguay
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; Medical School (Faculty of Medicine), Sao Paulo State University (UNESP), Brazil; University of Queensland, Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston, 4029, Queensland, Australia; Tecnologico de Monterrey, Eutra, The Institute for Obesity Research (IOR), School of Medicine and Health Sciences, Monterrey, Nuevo León, Mexico
| | - Garth L Nicolson
- Department of Molecular Pathology, The Institute for Molecular Medicine, Huntington Beach, CA, USA
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Razzaghy-Azar M, Saeedi S, Dayani SB, Enayati S, Abbasi F, Hashemian S, Eshraghi P, Karimdadi S, Tajdini P, Vakili R, Amoli MM, Yaghootkar H. Investigating Genetic Mutations in a Large Cohort of Iranian Patients with Congenital Hyperinsulinism. J Clin Res Pediatr Endocrinol 2022; 14:87-95. [PMID: 34927408 PMCID: PMC8900073 DOI: 10.4274/jcrpe.galenos.2021.2021.0071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
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.
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Affiliation(s)
- Maryam Razzaghy-Azar
- Tehran University of Medical Sciences, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Metabolic Disorders Research Centre, Tehran, Iran,Iran University of Medical Sciences, H. Aliasghar Hospital, Tehran, Iran
| | - Saeedeh Saeedi
- Tehran University of Medical Sciences, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Metabolic Disorders Research Centre, Tehran, Iran,Tehran University of Medical Sciences, Endocrinology and Metabolism Clinical Sciences Institute, Endocrinology and Metabolism Research Center, Tehran, Iran
| | - Sepideh Borhan Dayani
- Tehran University of Medical Sciences, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Metabolic Disorders Research Centre, Tehran, Iran
| | - Samaneh Enayati
- Tehran University of Medical Sciences, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Metabolic Disorders Research Centre, Tehran, Iran
| | - Farzaneh Abbasi
- Tehran University of Medical Sciences, Children’s Medical Center Hospital, Growth and Development Research Center, Tehran, Iran
| | - Somayyeh Hashemian
- Mashhad University of Medical Sciences, Faculty of Medicine, Akbar Hospital, Department of Pediatric Diseases, Mashhad, Iran
| | - Peyman Eshraghi
- Mashhad University of Medical Sciences, Faculty of Medicine, Akbar Hospital, Department of Pediatric Diseases, Mashhad, Iran
| | - Siroos Karimdadi
- Mashhad University of Medical Sciences, Faculty of Medicine, Akbar Hospital, Department of Pediatric Diseases, Mashhad, Iran
| | - Parisa Tajdini
- Tehran University of Medical Sciences, Children’s Medical Center Hospital, Growth and Development Research Center, Tehran, Iran
| | - Rahim Vakili
- Mashhad University of Medical Sciences, Faculty of Medicine, Akbar Hospital, Department of Pediatric Diseases, Mashhad, Iran
| | - Mahsa M. Amoli
- Tehran University of Medical Sciences, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Metabolic Disorders Research Centre, Tehran, Iran
| | - Hanieh Yaghootkar
- University of Exeter, College of Medicine and Health, Genetics of Complex Traits, London; University of Westminster, School of Life Sciences, Research Centre for Optimal Health, London, England; Luleå University of Technology, Department of Health Sciences, Division of Medical Sciences, Luleå, Sweden,* Address for Correspondence: University of Exeter, College of Medicine and Health, Genetics of Complex Traits, London, England E-mail:
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Wieland I, Schanze I, Felgendreher IM, Barthlen W, Vogelgesang S, Mohnike K, Zenker M. Integration of genomic analysis and transcript expression of ABCC8 and KCNJ11 in focal form of congenital hyperinsulinism. Front Endocrinol (Lausanne) 2022; 13:1015244. [PMID: 36339418 PMCID: PMC9634566 DOI: 10.3389/fendo.2022.1015244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 10/03/2022] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND The focal form of CHI is caused by an autosomal recessive pathogenic variant affecting the paternal homologue of genes ABCC8 or KCNJ11 and a second somatic event specifically occurring in the affected islet of Langerhans. The approach of this study was to integrate the genetic changes occurring in pancreatic focal lesions of CHI at the genomic and transcriptional level. RESEARCH DESIGN AND METHODS Patients receiving therapeutic surgery and with proven ABCC8 or KCNJ11 pathogenic variants were selected and analyzed for loss of heterozygosity (LOH), changes in copy number and uniparental disomy (UPD) on the short am of chromosome 11 by molecular microarray analysis and methylation-specific MLPA. Gene expression was analyzed by RT-PCR and Massive Analysis of cDNA Ends (MACE). RESULTS Both genes, ABCC8 and KCNJ11, are located in proximity to the Beckwith-Wiedemann (BWS) imprinting control region on chromosome 11p15. Somatic paternal uniparental isodisomy (UPD) at chromosome 11p was identified as second genetic event in focal lesions resulting in LOH and monoallelic expression of the mutated ABCC8/KCNJ11 alleles. Of five patients with samples available for microarray analysis, the breakpoints of UPD on chromosome 11p were different. Samples of two patients were analyzed further for changes in gene expression. Profound downregulation of growth suppressing genes CDKN1 and H19 was detected in focal lesions whereas growth promoting gene ASCL2 and pancreatic transcription factors of the endocrine cell lineage were upregulated. CONCLUSIONS Paternal UPD on the short arm of chromosome 11 appears to be the major second genetic event specifically within focal lesions of CHI but no common breakpoint for UDP can be delineated. We show for the first time upregulation of growth promoting ASCL2 (achaete-scute homolog 2) suggestive of a driving factor in postnatal focal expansion in addition to downregulation of growth suppressing genes CDKN1C and H19.
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Affiliation(s)
- Ilse Wieland
- Institute of Human Genetics, University Hospital Otto-von-Guericke- University Magdeburg, Magdeburg, Germany
- *Correspondence: Ilse Wieland,
| | - Ina Schanze
- Institute of Human Genetics, University Hospital Otto-von-Guericke- University Magdeburg, Magdeburg, Germany
| | - Ina Marianti Felgendreher
- Institute of Human Genetics, University Hospital Otto-von-Guericke- University Magdeburg, Magdeburg, Germany
| | - Winfried Barthlen
- Department of Pediatric Surgery, Protestant Hospital of Bethel Foundation, University Hospital OWL, University of Bielefeld, Bielefeld, Germany
| | - Silke Vogelgesang
- University Medicine, Institute of Pathology, University of Greifswald, Greifswald, Germany
| | - Klaus Mohnike
- Dept of Pediatrics, University Hospital Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Martin Zenker
- Institute of Human Genetics, University Hospital Otto-von-Guericke- University Magdeburg, Magdeburg, Germany
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Abstract
K+ channels enable potassium to flow across the membrane with great selectivity. There are four K+ channel families: voltage-gated K (Kv), calcium-activated (KCa), inwardly rectifying K (Kir), and two-pore domain potassium (K2P) channels. All four K+ channels are formed by subunits assembling into a classic tetrameric (4x1P = 4P for the Kv, KCa, and Kir channels) or tetramer-like (2x2P = 4P for the K2P channels) architecture. These subunits can either be the same (homomers) or different (heteromers), conferring great diversity to these channels. They share a highly conserved selectivity filter within the pore but show different gating mechanisms adapted for their function. K+ channels play essential roles in controlling neuronal excitability by shaping action potentials, influencing the resting membrane potential, and responding to diverse physicochemical stimuli, such as a voltage change (Kv), intracellular calcium oscillations (KCa), cellular mediators (Kir), or temperature (K2P).
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Structure based analysis of K ATP channel with a DEND syndrome mutation in murine skeletal muscle. Sci Rep 2021; 11:6668. [PMID: 33758250 PMCID: PMC7988048 DOI: 10.1038/s41598-021-86121-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
Developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome, the most severe end of neonatal diabetes mellitus, is caused by mutation in the ATP-sensitive potassium (KATP) channel. In addition to diabetes, DEND patients present muscle weakness as one of the symptoms, and although the muscle weakness is considered to originate in the brain, the pathological effects of mutated KATP channels in skeletal muscle remain elusive. Here, we describe the local effects of the KATP channel on muscle by expressing the mutation present in the KATP channels of the DEND syndrome in the murine skeletal muscle cell line C2C12 in combination with computer simulation. The present study revealed that the DEND mutation can lead to a hyperpolarized state of the muscle cell membrane, and molecular dynamics simulations based on a recently reported high-resolution structure provide an explanation as to why the mutation reduces ATP sensitivity and reveal the changes in the local interactions between ATP molecules and the channel.
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Scala R, Maqoud F, Zizzo N, Mele A, Camerino GM, Zito FA, Ranieri G, McClenaghan C, Harter TM, Nichols CG, Tricarico D. Pathophysiological Consequences of KATP Channel Overactivity and Pharmacological Response to Glibenclamide in Skeletal Muscle of a Murine Model of Cantù Syndrome. Front Pharmacol 2020; 11:604885. [PMID: 33329006 PMCID: PMC7734337 DOI: 10.3389/fphar.2020.604885] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/03/2020] [Indexed: 12/11/2022] Open
Abstract
Cantù syndrome (CS) arises from mutations in ABCC9 and KCNJ8 genes that lead to gain of function (GOF) of ATP-sensitive potassium (KATP) channels containing SUR2A and Kir6.1 subunits, respectively, of KATP channels. Pathological consequences of CS have been reported for cardiac and smooth muscle cells but consequences in skeletal muscle are unknown. Children with CS show muscle hypotonia and adult manifest fatigability. We analyzed muscle properties of Kir6.1[V65M] CS mice, by measurements of forelimb strength and ultrasonography of hind-limb muscles, as well as assessing KATP channel properties in native Flexor digitorum brevis (FDB) and Soleus (SOL) fibers by the patch-clamp technique in parallel with histopathological, immunohistochemical and Polymerase Chain Reaction (PCR) analysis. Forelimb strength was lower in Kir6.1wt/VM mice than in WT mice. Also, a significant enhancement of echodensity was observed in hind-limb muscles of Kir6.1wt/VM mice relative to WT, suggesting the presence of fibrous tissue. There was a higher KATP channel current amplitude in Kir6.1wt/VM FDB fibers relative to WT and a reduced response to glibenclamide. The IC50 of glibenclamide to block KATP channels in FDB fibers was 1.3 ± 0.2 × 10−7 M in WT and 1.2 ± 0.1 × 10−6 M in Kir6.1wt/VM mice, respectively; and it was 1.2 ± 0.4 × 10−7 M in SOL WT fibers but not measurable in Kir6.1wt/VM fibers. The sensitivity of the KATP channel to MgATP was not modified in Kir6.1wt/VM fibers. Histopathological/immunohistochemical analysis of SOL revealed degeneration plus regressive-necrotic lesions with regeneration, and up-regulation of Atrogin-1, MuRF1, and BNIP3 mRNA/proteins in Kir6.1wt/VM mice. Kir6.1wt/VM mutation in skeletal muscle leads to changes of the KATP channel response to glibenclamide in FDB and SOL fibers, and it is associated with histopathological and gene expression changes in slow-twitch muscle, suggesting marked atrophy and autophagy.
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Affiliation(s)
- Rosa Scala
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Fatima Maqoud
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Nicola Zizzo
- Section of Veterinary Pathology and Comparative Oncology, Department of Veterinary Medicine, University of Bari "Aldo Moro", Valenzano, Italy
| | - Antonietta Mele
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Giulia Maria Camerino
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
| | - Francesco Alfredo Zito
- Interventional and Medical Oncology Unit, Department of Pathology National Cancer Research Centre, IRCCS Istituto Tumori Giovanni Paolo II, Bari, Italy
| | - Girolamo Ranieri
- Interventional and Medical Oncology Unit, Department of Pathology National Cancer Research Centre, IRCCS Istituto Tumori Giovanni Paolo II, Bari, Italy
| | - Conor McClenaghan
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, United States
| | - Theresa M Harter
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, United States
| | - Colin G Nichols
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, United States
| | - Domenico Tricarico
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari "Aldo Moro", Bari, Italy
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Kumar A, Pramanik S, Ghosh S, Saha B. Neonatal Hypoglycaemia due to ABCC8 Gene Mutation. Indian J Endocrinol Metab 2020; 24:555-558. [PMID: 33643876 PMCID: PMC7906097 DOI: 10.4103/ijem.ijem_780_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 12/05/2020] [Accepted: 12/10/2020] [Indexed: 02/05/2023] Open
Affiliation(s)
- Ashok Kumar
- Consultant Endocrinologist, KHIMS Hospitals, Khammam, Telangana, India
| | | | - Sujoy Ghosh
- Department of Endocrinology and Metabolism, Institute of Post Graduate Medical Education and Research and Seth Sukhlal Karnani Memorial Hospital, Kolkata, West Bengal, India
| | - Bijan Saha
- Department of Neonatology, Institute of Post Graduate Medical Education and Research and Seth Sukhlal Karnani Memorial Hospital, Kolkata, West Bengal, India
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Boodhansingh KE, Kandasamy B, Mitteer L, Givler S, De Leon DD, Shyng S, Ganguly A, Stanley CA. Novel dominant K ATP channel mutations in infants with congenital hyperinsulinism: Validation by in vitro expression studies and in vivo carrier phenotyping. Am J Med Genet A 2019; 179:2214-2227. [PMID: 31464105 PMCID: PMC6852436 DOI: 10.1002/ajmg.a.61335] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/02/2019] [Accepted: 08/05/2019] [Indexed: 12/17/2022]
Abstract
Inactivating mutations in the genes encoding the two subunits of the pancreatic beta-cell KATP channel, ABCC8 and KCNJ11, are the most common finding in children with congenital hyperinsulinism (HI). Interpreting novel missense variants in these genes is problematic, because they can be either dominant or recessive mutations, benign polymorphisms, or diabetes mutations. This report describes six novel missense variants in ABCC8 and KCNJ11 that were identified in 11 probands with congenital HI. One of the three ABCC8 mutations (p.Ala1458Thr) and all three KCNJ11 mutations were associated with responsiveness to diazoxide. Sixteen family members carried the ABCC8 or KCNJ11 mutations; only two had hypoglycemia detected at birth and four others reported symptoms of hypoglycemia. Phenotype testing of seven adult mutation carriers revealed abnormal protein-induced hypoglycemia in all; fasting hypoketotic hypoglycemia was demonstrated in four of the seven. All of six mutations were confirmed to cause dominant pathogenic defects based on in vitro expression studies in COSm6 cells demonstrating normal trafficking, but reduced responses to MgADP and diazoxide. These results indicate a combination of in vitro and in vivo phenotype tests can be used to differentiate dominant from recessive KATP channel HI mutations and personalize management of children with congenital HI.
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Affiliation(s)
- Kara E. Boodhansingh
- Division of Endocrinology and DiabetesThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
| | - Balamurugan Kandasamy
- Department of Biochemistry and Molecular BiologyOregon Health & Science UniversityPortlandOregon
| | - Lauren Mitteer
- Division of Endocrinology and DiabetesThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
| | - Stephanie Givler
- Division of Endocrinology and DiabetesThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
| | - Diva D. De Leon
- Division of Endocrinology and DiabetesThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
- Department of PediatricsPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvania
| | - Show‐Ling Shyng
- Department of Biochemistry and Molecular BiologyOregon Health & Science UniversityPortlandOregon
| | - Arupa Ganguly
- Department of GeneticsThe Perelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvania
| | - Charles A. Stanley
- Division of Endocrinology and DiabetesThe Children's Hospital of PhiladelphiaPhiladelphiaPennsylvania
- Department of PediatricsPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPennsylvania
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Kostopoulou E, Shah P. Hyperinsulinaemic hypoglycaemia-an overview of a complex clinical condition. Eur J Pediatr 2019; 178:1151-1160. [PMID: 31243576 DOI: 10.1007/s00431-019-03414-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 12/18/2022]
Abstract
Hyperinsulinaemic hypoglycaemia (HH) is a major cause of hypoglycaemia in the neonatal period, infancy and childhood. It is caused by unsuppressed insulin secretion in the setting of hypoglycaemia and carries a high risk of significant neurological sequelae, such as cognitive impairment. Genetic mutations have been implicated in the pathogenesis of the condition. Other causes include intra-uterine growth retardation, perinatal asphyxia, maternal diabetes mellitus and syndromes, such as Beckwith-Wiedemann. Based on the aetiology, the clinical presentation can range from absence of symptoms to the typical adrenergic symptoms and coma and even death. The diagnosis is based on biochemical findings and the gold-standard imaging technique is 18F-DOPA PET/CT scanning. Treatment options involve medications, such as diazoxide, nifedipine, glucagon and octreotide, as well as surgery. Novel treatment, such as long-acting octreotide, lanreotide and sirolimus, may be used as an alternative to pancreatectomy. Potential future medical treatments include exendin, a GLP-1 receptor antagonist, and glucagon infusion via a pump.Conclusion: Advances in the fields of genetic testing, imaging techniques and medical treatment are beginning to provide novel insights into earlier detection, less invasive treatment approaches and fewer complications associated with the complex entity of hyperinsulinaemic hypoglycaemia. What is Known: • HH is caused by dysregulated insulin release from the β cell due to genetic mutations and carries a risk for complications, such as neurocognitive impairment. 18F-DOPA PET/CT scanning is presented as the gold-standard imaging technique currently in children with hyperinsulinaemic hypoglycaemia. • Clinical presentation is heterogeneous and treatment options include medical therapy and pancreatectomy. What is New: • 18F-DOPA PET/CT is indicated in suspected focal CHI due to paternal transmitted mutations in ABCC8 or KCNJ11. • Novel treatment options have been introduced, such as long-acting octreotide, lanreotide, sirolimus and selective nonpeptide somatostatin receptor subtype 5 (SSTR5) agonists. Future medical treatments include exendin, a GLP-1 antagonist, and glucagon infusion via a pump. However, all these options are off-label at present.
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Affiliation(s)
- Eirini Kostopoulou
- Research Laboratory of the Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics, School of Medicine, University of Patras, 26500, Patras, Greece.
| | - Pratik Shah
- Endocrinology Department, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,Genetics and Genomic Medicine Programme, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
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10
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Tinker A, Aziz Q, Li Y, Specterman M. ATP‐Sensitive Potassium Channels and Their Physiological and Pathophysiological Roles. Compr Physiol 2018; 8:1463-1511. [DOI: 10.1002/cphy.c170048] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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11
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Giri D, Vignola ML, Gualtieri A, Scagliotti V, McNamara P, Peak M, Didi M, Gaston-Massuet C, Senniappan S. Novel FOXA2 mutation causes Hyperinsulinism, Hypopituitarism with Craniofacial and Endoderm-derived organ abnormalities. Hum Mol Genet 2018; 26:4315-4326. [PMID: 28973288 DOI: 10.1093/hmg/ddx318] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 07/31/2017] [Indexed: 12/12/2022] Open
Abstract
Congenital hypopituitarism (CH) is characterized by the deficiency of one or more pituitary hormones and can present alone or in association with complex disorders. Congenital hyperinsulinism (CHI) is a disorder of unregulated insulin secretion despite hypoglycaemia that can occur in isolation or as part of a wider syndrome. Molecular diagnosis is unknown in many cases of CH and CHI. The underlying genetic etiology causing the complex phenotype of CH and CHI is unknown. In this study, we identified a de novo heterozygous mutation in the developmental transcription factor, forkhead box A2, FOXA2 (c.505T>C, p.S169P) in a child with CHI and CH with craniofacial dysmorphic features, choroidal coloboma and endoderm-derived organ malformations in liver, lung and gastrointestinal tract by whole exome sequencing. The mutation is at a highly conserved residue within the DNA binding domain. We demonstrated strong expression of Foxa2 mRNA in the developing hypothalamus, pituitary, pancreas, lungs and oesophagus of mouse embryos using in situ hybridization. Expression profiling on human embryos by immunohistochemistry showed strong expression of hFOXA2 in the neural tube, third ventricle, diencephalon and pancreas. Transient transfection of HEK293T cells with Wt (Wild type) hFOXA2 or mutant hFOXA2 showed an impairment in transcriptional reporter activity by the mutant hFOXA2. Further analyses using western blot assays showed that the FOXA2 p.(S169P) variant is pathogenic resulting in lower expression levels when compared with Wt hFOXA2. Our results show, for the first time, the causative role of FOXA2 in a complex congenital syndrome with hypopituitarism, hyperinsulinism and endoderm-derived organ abnormalities.
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Affiliation(s)
- Dinesh Giri
- Department of Paediatric Endocrinology, Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK.,Department of Women and Children's Health, Institute in the Park, University of Liverpool, Liverpool L12 2AP, UK
| | - Maria Lillina Vignola
- Centre for Endocrinology, William Harvey Research Institute, Barts & the London School of Medicine, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK
| | - Angelica Gualtieri
- Centre for Endocrinology, William Harvey Research Institute, Barts & the London School of Medicine, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK
| | - Valeria Scagliotti
- Centre for Endocrinology, William Harvey Research Institute, Barts & the London School of Medicine, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK
| | - Paul McNamara
- Department of Women and Children's Health, Institute in the Park, University of Liverpool, Liverpool L12?2AP, UK
| | - Matthew Peak
- NIHR Alder Hey Clinical Research Facility for Experimental Medicine, Alder Hey Children's NHS Foundation Trust, Liverpool, L12 2AP, UK
| | - Mohammed Didi
- Department of Paediatric Endocrinology, Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK
| | - Carles Gaston-Massuet
- Centre for Endocrinology, William Harvey Research Institute, Barts & the London School of Medicine, Queen Mary University of London, John Vane Science Centre, Charterhouse Square, London EC1M 6BQ, UK
| | - Senthil Senniappan
- Department of Paediatric Endocrinology, Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK.,Department of Women and Children's Health, Institute in the Park, University of Liverpool, Liverpool L12 2AP, UK
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12
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Xu M, Hu H, Deng D, Chen M, Xu Z, Wang Y. Prediabetes is associated with genetic variations in the gene encoding the Kir6.2 subunit of the pancreatic ATP-sensitive potassium channel (KCNJ11): A case-control study in a Han Chinese youth population. J Diabetes 2018; 10:121-129. [PMID: 28449408 DOI: 10.1111/1753-0407.12565] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 04/06/2017] [Accepted: 04/24/2017] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The E23K variant of the potassium voltage-gated channel subfamily J member 11 (KCNJ11) gene has been reported to be associated with type 2 diabetes (T2D) in many populations. However, little is known about the role of E23K in the development of prediabetes in Chinese youth. METHODS To investigate the role of E23K in the development of prediabetes, 279 subjects with prediabetes and 240 normal controls (mean [± SD] age 18.1 ± 3.2 and 17.8 ± 4.3 years, respectively) were recruited to the study. Height, weight, and hip and waist circumferences were measured by trained physicians. Genotyping of KCNJ11 polymorphisms and clinical laboratory tests to determine cholesterol, triglyceride (TG), blood glucose, and insulin levels were performed. RESULTS The carrier rate of K23 allele-containing genotypes was higher for prediabetic than control subjects (P = 0.005). Logistic regression analyses revealed that higher body mass index percentiles (P = 0.013), lower insulin levels at 30 min during an oral glucose tolerance test (P = 0.001), a higher ratio of total cholesterol: high-density lipoprotein cholesterol (P = 0.001), and a K allele-containing genotype (P = 0.019) are independent risk factors for prediabetes in Chinese Han youth. Furthermore, K23 allele-containing genotypes were associated with impaired indices of insulin secretion and β-cell function in female youth with prediabetes. These effects were not seen in male youth with prediabetes. CONCLUSIONS The results confirm that the common E23K polymorphism of KCNJ11 carries a higher susceptibility to the development of prediabetes in the Chinese Han population. The results suggest that E23K may have a greater effect on the development of T2D in female Chinese youth.
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Affiliation(s)
- Min Xu
- Department of Endocrinology, The First Hospital of An Hui Medical University, Hefei, China
| | - Honglin Hu
- Department of Endocrinology, The First Hospital of An Hui Medical University, Hefei, China
| | - Datong Deng
- Department of Endocrinology, The First Hospital of An Hui Medical University, Hefei, China
| | - Mingwei Chen
- Department of Endocrinology, The First Hospital of An Hui Medical University, Hefei, China
| | - Zhenshan Xu
- AnHui AnKe Biotechnology Group, Hefei, China
| | - Youmin Wang
- Department of Endocrinology, The First Hospital of An Hui Medical University, Hefei, China
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13
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Abstract
Since the discovery of the KATP channel in 1983, numerous studies have revealed its physiological functions. The KATP channel is expressed in various organs, including the pancreas, brain and skeletal muscles. It functions as a "metabolic sensor" that converts the metabolic status to electrical activity. In pancreatic beta-cells, the KATP channel regulates the secretion of insulin by sensing a change in the blood glucose level and thus maintains glucose homeostasis. In 2004, heterozygous gain-of-function mutations in the KCNJ11 gene, which encodes the Kir6.2 subunit of the KATP channel, were found to cause neonatal diabetes. In some mutations, diabetes is accompanied by severe neurological symptoms [developmental delay, epilepsy, neonatal diabetes (DEND) syndrome]. This review focuses on mutations of Kir6.2, the pore-forming subunit and sulfonylurea receptor (SUR) 1, the regulatory subunit of the KATP channel, which cause neonatal diabetes/DEND syndrome and also discusses the findings of the pathological mechanisms that are associated with neonatal diabetes, and its neurological features.
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Affiliation(s)
- Kenju Shimomura
- Department of Medical Electrophysiology, Fukushima Medical University School of Medicine, Japan
| | - Yuko Maejima
- Department of Medical Electrophysiology, Fukushima Medical University School of Medicine, Japan
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14
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Cho JH, Kang E, Lee BH, Kim GH, Choi JH, Yoo HW. DEND Syndrome with Heterozygous KCNJ11 Mutation Successfully Treated with Sulfonylurea. J Korean Med Sci 2017; 32:1042-1045. [PMID: 28480665 PMCID: PMC5426229 DOI: 10.3346/jkms.2017.32.6.1042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/04/2016] [Indexed: 12/27/2022] Open
Abstract
Permanent neonatal diabetes mellitus (PNDM) is caused by mutations in the ATP-sensitive potassium channel (KATP channel) subunits. Developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome is the most severe form of PNDM and is characterized by various neurologic features. We report on a patient with DEND syndrome following initial misdiagnosis with type 1 DM, who was successfully switched from insulin to sulfonylurea therapy. A 50-day-old male presented with fever and seizure, complicated by persistent hyperglycemia. Insulin therapy was initiated. At 10 months of age, the patient was unable to hold his head up and make eye contact with others. At 17.9 years of age, direct sequencing of KCNJ11 identified a heterozygous mutation of c.602G>A (p.R201H). Since then, treatment with gliclazide was initiated and the insulin dose was gradually reduced. Following 3 months, insulin was discontinued with a gliclazide dose of 2.4 mg/kg. The patient continued to have excellent glycemic control with a glycated hemoglobin (HbA1c) level of 5.8% after 5 months. However, the patient's psychomotor retardation did not improve. This study reports the first case of DEND syndrome in Korea caused by a KCNJ11 mutation and emphasizes the necessity to screen mutations in KATP channel genes in patients with neonatal diabetes.
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MESH Headings
- Base Sequence
- Brain/diagnostic imaging
- DNA/chemistry
- DNA/isolation & purification
- DNA/metabolism
- Diabetes Mellitus/diagnosis
- Diabetes Mellitus/drug therapy
- Diabetes Mellitus/genetics
- Epilepsy/diagnosis
- Epilepsy/drug therapy
- Epilepsy/genetics
- Gliclazide/therapeutic use
- Glycated Hemoglobin/analysis
- Heterozygote
- Humans
- Hypoglycemic Agents/therapeutic use
- Infant
- Infant, Newborn
- Infant, Newborn, Diseases/diagnosis
- Infant, Newborn, Diseases/drug therapy
- Infant, Newborn, Diseases/genetics
- Insulin/therapeutic use
- Magnetic Resonance Imaging
- Male
- Polymorphism, Single Nucleotide
- Potassium Channels, Inwardly Rectifying/genetics
- Psychometrics
- Psychomotor Disorders/diagnosis
- Psychomotor Disorders/drug therapy
- Psychomotor Disorders/genetics
- Sequence Analysis, DNA
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Affiliation(s)
- Ja Hyang Cho
- Department of Pediatrics, University of Ulsan College of Medicine, Asan Medical Center Children's Hospital, Seoul, Korea
| | - Eungu Kang
- Department of Pediatrics, University of Ulsan College of Medicine, Asan Medical Center Children's Hospital, Seoul, Korea
| | - Beom Hee Lee
- Department of Pediatrics, University of Ulsan College of Medicine, Asan Medical Center Children's Hospital, Seoul, Korea
| | - Gu Hwan Kim
- Medical Genetics Center, University of Ulsan College of Medicine, Asan Medical Center Children's Hospital, Seoul, Korea
| | - Jin Ho Choi
- Department of Pediatrics, University of Ulsan College of Medicine, Asan Medical Center Children's Hospital, Seoul, Korea
| | - Han Wook Yoo
- Department of Pediatrics, University of Ulsan College of Medicine, Asan Medical Center Children's Hospital, Seoul, Korea
- Medical Genetics Center, University of Ulsan College of Medicine, Asan Medical Center Children's Hospital, Seoul, Korea.
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15
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Kandaswamy L, Raghavan R, Pappachan JM. Spontaneous hypoglycemia: diagnostic evaluation and management. Endocrine 2016; 53:47-57. [PMID: 26951054 DOI: 10.1007/s12020-016-0902-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 02/15/2016] [Indexed: 02/07/2023]
Abstract
Spontaneous hypoglycemia is a puzzling clinical problem and an important reason for referral to endocrinologists. Several clinical conditions such as insulinomas, non-insulinoma pancreatogenous hypoglycemia syndrome, insulin autoimmune syndrome, postprandial hypoglycemia (reactive hypoglycemia), non-islet cell tumor hypoglycemia, primary adrenal insufficiency, hypopituitarism, and critical illness can be associated with spontaneous hypoglycemia. Rarely, in patients with mental health issues, factious hypoglycemia from extrinsic insulin use or ingestion of oral hypoglycemic agents can obfuscate the clinical picture for clinicians trying to identify an organic cause. In those presenting with Whipple's triad (symptoms ± signs of hypoglycemia, low plasma glucose, and resolution symptoms ± signs after hypoglycemia correction), a 72-h supervised fast test with measurement of plasma insulin, c-peptide, pro-insulin, and beta-hydroxybutyrate levels, coupled with plasma/urine sulphonylurea screen, forms the first step in diagnostic evaluation. A mixed meal test is preferable for those with predominantly postprandial symptoms. Additional non-invasive and/or invasive diagnostic evaluation is necessary if an organic hypoglycemic disorder is suspected. With the aid of a few brief clinical case scenarios, we discuss the diagnostic evaluation and management of spontaneous hypoglycemia through this comprehensive article.
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Affiliation(s)
- Leelavathy Kandaswamy
- Department of Endocrinology & Diabetes, New Cross Hospital, The Royal Wolverhampton Hospitals NHS Trust, Wolverhampton, WV10 0QP, UK
| | - Rajeev Raghavan
- Department of Endocrinology & Diabetes, New Cross Hospital, The Royal Wolverhampton Hospitals NHS Trust, Wolverhampton, WV10 0QP, UK
| | - Joseph M Pappachan
- Department of Endocrinology & Diabetes, New Cross Hospital, The Royal Wolverhampton Hospitals NHS Trust, Wolverhampton, WV10 0QP, UK.
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16
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Abstract
CONTEXT Congenital hyperinsulinism (HI) is the most common cause of hypoglycemia in children. The risk of permanent brain injury in infants with HI continues to be as high as 25-50% due to delays in diagnosis and inadequate treatment. Congenital HI has been described since the birth of the JCEM under various terms, including "idiopathic hypoglycemia of infancy," "leucine-sensitive hypoglycemia," or "nesidioblastosis." EVIDENCE ACQUISITION In the past 20 years, it has become apparent that HI is caused by genetic defects in the pathways that regulate pancreatic β-cell insulin secretion. EVIDENCE SYNTHESIS There are now 11 genes associated with monogenic forms of HI (ABCC8, KCNJ11, GLUD1, GCK, HADH1, UCP2, MCT1, HNF4A, HNF1A, HK1, PGM1), as well as several syndromic genetic forms of HI (eg, Beckwith-Wiedemann, Kabuki, and Turner syndromes). HI is also the cause of hypoglycemia in transitional neonatal hypoglycemia and in persistent hypoglycemia in various groups of high-risk neonates (such as birth asphyxia, small for gestational age birthweight, infant of diabetic mother). Management of HI is one of the most difficult problems faced by pediatric endocrinologists and frequently requires difficult choices, such as near-total pancreatectomy and/or highly intensive care with continuous tube feedings. For 50 years, diazoxide, a KATP channel agonist, has been the primary drug for infants with HI; however, it is ineffective in most cases with mutations of ABCC8 or KCNJ11, which constitute the majority of infants with monogenic HI. CONCLUSIONS Genetic mutation testing has become standard of care for infants with HI and has proven to be useful not only in projecting prognosis and family counseling, but also in diagnosing infants with surgically curable focal HI lesions. (18)F-fluoro-L-dihydroxyphenylalanine ((18)F-DOPA) PET scans have been found to be highly accurate for localizing such focal lesions preoperatively. New drugs under investigation provide hope for improving the outcomes of children with HI.
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Affiliation(s)
- Charles A Stanley
- Division of Endocrinology, The Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
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17
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Kalish JM, Boodhansingh KE, Bhatti TR, Ganguly A, Conlin LK, Becker SA, Givler S, Mighion L, Palladino AA, Adzick NS, De León DD, Stanley CA, Deardorff MA. Congenital hyperinsulinism in children with paternal 11p uniparental isodisomy and Beckwith-Wiedemann syndrome. J Med Genet 2016; 53:53-61. [PMID: 26545876 PMCID: PMC4740975 DOI: 10.1136/jmedgenet-2015-103394] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/16/2015] [Indexed: 01/03/2023]
Abstract
BACKGROUND Congenital hyperinsulinism (HI) can have monogenic or syndromic causes. Although HI has long been recognised to be common in children with Beckwith-Wiedemann syndrome (BWS), the underlying mechanism is not known. METHODS We characterised the clinical features of children with both HI and BWS/11p overgrowth spectrum, evaluated the contribution of KATP channel mutations to the molecular pathogenesis of their HI and assessed molecular pathogenesis associated with features of BWS. RESULTS We identified 28 children with HI and BWS/11p overgrowth from 1997 to 2014. Mosaic paternal uniparental isodisomy for chromosome 11p (pUPD11p) was noted in 26/28 cases. Most were refractory to diazoxide treatment and half required subtotal pancreatectomies. Patients displayed a wide range of clinical features from classical BWS to only mild hemihypertrophy (11p overgrowth spectrum). Four of the cases had a paternally transmitted KATP mutation and had a much more severe HI course than patients with pUPD11p alone. CONCLUSIONS We found that patients with pUPD11p-associated HI have a persistent and severe HI phenotype compared with transient hypoglycaemia of BWS/11p overgrowth patients caused by other aetiologies. Testing for pUPD11p should be considered in all patients with persistent congenital HI, especially for those without an identified HI gene mutation.
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Affiliation(s)
- Jennifer M Kalish
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kara E Boodhansingh
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Tricia R Bhatti
- Department of Pathology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Arupa Ganguly
- Department of Genetics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Laura K Conlin
- Department of Pathology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Susan A Becker
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Stephanie Givler
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Lindsey Mighion
- Department of Genetics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrew A Palladino
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - N Scott Adzick
- Department of Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Diva D De León
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Charles A Stanley
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Division of Endocrinology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Matthew A Deardorff
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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18
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Total pancreatectomy for the management of refractory post-gastric bypass hypoglycemia. Dig Dis Sci 2015; 60:1505-9. [PMID: 25344909 DOI: 10.1007/s10620-014-3408-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/15/2014] [Indexed: 12/19/2022]
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19
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Screening for Mutations in ABCC8 and KCNJ11 Genes in Saudi Persistent Hyperinsulinemic Hypoglycemia of Infancy (PHHI) Patients. Genes (Basel) 2015; 6:206-15. [PMID: 25871929 PMCID: PMC4488661 DOI: 10.3390/genes6020206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 03/04/2015] [Accepted: 03/13/2015] [Indexed: 11/17/2022] Open
Abstract
The autosomal recessive form of persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is associated with mutations in either ABCC8 or KCNJ11 genes. In the present study, we describe the clinical features and results of genetic analysis of 13 Saudi Arabian patients with PHHI. Clinically, most patients presented with infantile seizures and/or developmental delay, with a subset of patients who were also found to have abnormal brain imaging and electrophysiological studies. Interestingly no coding pathogenic mutations were identified in these two genes by direct sequencing. However, two splice variants were identified in ABCC8 gene in two patients, and a large deletion of exons 1-22 of the ABCC8 gene was identified in three patients. Our data shows that large deletions in ABCC8 gene are the common genetic mechanism in the Saudi population.
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20
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Del Roio Liberatore R, Ramos PM, Guerra G, Manna TD, Silva IN, Martinelli CE. Clinical and molecular data from 61 Brazilian cases of Congenital Hyperinsulinemic Hypoglycemia. Diabetol Metab Syndr 2015; 7:5. [PMID: 25972930 PMCID: PMC4429972 DOI: 10.1186/1758-5996-7-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/14/2015] [Indexed: 11/10/2022] Open
Abstract
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.
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Affiliation(s)
- Raphael Del Roio Liberatore
- />Ribeirão Preto Medical School, University of São Paulo, Rua Elzira Sammarco Palma, 400/43, Ribeirão Preto, SP Brazil
| | - Priscila Manzini Ramos
- />Ribeirão Preto Medical School, University of São Paulo, Rua Elzira Sammarco Palma, 400/43, Ribeirão Preto, SP Brazil
| | - Gil Guerra
- />Department of Pediatrics, School of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP Brazil
| | - Thais Della Manna
- />Pediatric Endocrine Unit, Instituto da Criança-Hospital das Clínicas, Universidade de São Paulo (USP), São Paulo, SP Brazil
| | - Ivani Novato Silva
- />Pediatrics Department, Medical School/ Hospital das Clínicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Carlos Eduardo Martinelli
- />Ribeirão Preto Medical School, University of São Paulo, Rua Elzira Sammarco Palma, 400/43, Ribeirão Preto, SP Brazil
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21
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Yorifuji T, Masue M, Nishibori H. Congenital hyperinsulinism: global and Japanese perspectives. Pediatr Int 2014; 56:467-76. [PMID: 24865345 DOI: 10.1111/ped.12390] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/12/2014] [Indexed: 12/12/2022]
Abstract
Over the past 20 years, there has been remarkable progress in the diagnosis and treatment of congenital hyperinsulinism (CHI). These advances have been supported by the understanding of the molecular mechanism and the development of diagnostic modalities to identify the focal form of ATP-sensitive potassium channel CHI. Many patients with diazoxide-unresponsive focal CHI have been cured by partial pancreatectomy without developing postsurgical diabetes mellitus. Important novel findings on the genetic basis of the other forms of CHI have also been obtained, and several novel medical treatments have been explored. However, the management of patients with CHI is still far from ideal. First, state-of-the-art treatment is not widely available worldwide. Second, it appears that the management strategy needs to be adjusted according to the patient's ethnic group. Third, optimal management of patients with the diazoxide-unresponsive, diffuse form of CHI is still insufficient and requires further improvement. In this review, we describe the current landscape of this disorder, discuss the racial disparity of CHI using Japanese patients as an example, and briefly note unanswered questions and unmet needs that should be addressed in the near future.
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Affiliation(s)
- Tohru Yorifuji
- Pediatric Endocrinology and Metabolism, Children's Medical Center, Osaka City General Hospital, Osaka, Japan; Clinical Research Center, Osaka City General Hospital, Osaka, Japan; Department of Genetic Medicine, Osaka City General Hospital, Osaka, Japan
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22
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Avrahami D, Li C, Yu M, Jiao Y, Zhang J, Naji A, Ziaie S, Glaser B, Kaestner KH. Targeting the cell cycle inhibitor p57Kip2 promotes adult human β cell replication. J Clin Invest 2014; 124:670-4. [PMID: 24430183 DOI: 10.1172/jci69519] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 10/31/2013] [Indexed: 12/18/2022] Open
Abstract
Children with focal hyperinsulinism of infancy display a dramatic, non-neoplastic clonal expansion of β cells that have undergone mitotic recombination, resulting in paternal disomy of part of chromosome 11. This disomic region contains imprinted genes, including the gene encoding the cell cycle inhibitor p57Kip2 (CDKN1C), which is silenced as a consequence of the recombination event. We hypothesized that targeting p57Kip2 could stimulate adult human β cell replication. Indeed, when we suppressed CDKN1C expression in human islets obtained from deceased adult organ donors and transplanted them into hyperglycemic, immunodeficient mice, β cell replication increased more than 3-fold. The newly replicated cells retained properties of mature β cells, including the expression of β cell markers such as insulin, PDX1, and NKX6.1. Importantly, these newly replicated cells demonstrated normal glucose-induced calcium influx, further indicating β cell functionality. These findings provide a molecular explanation for the massive β cell replication that occurs in children with focal hyperinsulinism. These data also provided evidence that β cells from older humans, in which baseline replication is negligible, can be coaxed to re-enter and complete the cell cycle while maintaining mature β cell properties. Thus, controlled manipulation of this pathway holds promise for the expansion of β cells in patients with type 2 diabetes.
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23
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Jiang YD, Chuang LM, Pei D, Lee YJ, Wei JN, Sung FC, Chang TJ. Genetic Variations in the Kir6.2 Subunit (KCNJ11) of Pancreatic ATP-Sensitive Potassium Channel Gene Are Associated with Insulin Response to Glucose Loading and Early Onset of Type 2 Diabetes in Childhood and Adolescence in Taiwan. Int J Endocrinol 2014; 2014:983016. [PMID: 25309595 PMCID: PMC4189766 DOI: 10.1155/2014/983016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/20/2014] [Indexed: 11/18/2022] Open
Abstract
To investigate the role of E23K polymorphism of the KCNJ11 gene on early onset of type 2 diabetes in school-aged children/adolescents in Taiwan, we recruited 38 subjects with type 2 diabetes (ages 18.6 ± 6.6 years; body mass index percentiles 83.3 ± 15.4) and 69 normal controls (ages 17.3 ± 3.8 years; body mass index percentiles 56.7 ± 29.0) from a national surveillance for childhood/adolescent diabetes in Taiwan. We searched for the E23K polymorphism of the KCNJ11 gene. We found that type 2 diabetic subjects had higher carrier rate of E23K polymorphism of KCNJ11 gene than control subjects (P = 0.044). After adjusting for age, gender, body mass index percentiles, and fasting plasma insulin, the E23K polymorphism contributed to an increased risk for type 2 diabetes (P = 0.047). K23-allele-containing genotypes conferring increased plasma insulin level during OGTT in normal subjects. However, the diabetic subjects with the K23-allele-containing genotypes had lower fasting plasma insulin levels after adjustment of age and BMI percentiles. In conclusion, the E23K variant of the KCNJ11 gene conferred higher susceptibility to type 2 diabetes in children/adolescents. Furthermore, in normal glucose-tolerant children/adolescents, K23 allele carriers had a higher insulin response to oral glucose loading.
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Affiliation(s)
- Yi-Der Jiang
- Department of Internal Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan
| | - Lee-Ming Chuang
- Department of Internal Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan
- Graduate Institute of Preventive Medicine, School of Public Health, National Taiwan University, Taipei 10002, Taiwan
| | - Dee Pei
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Cardinal Tien Hospital, Xindian 23148, Taiwan
| | - Yann-Jinn Lee
- Department of Pediatrics, Mackay General Hospital, Taipei 10449, Taiwan
| | - Jun-Nan Wei
- Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan
| | - Fung-Chang Sung
- Institute of Environmental Health, College of Public Health, China Medical University, Taichung 40447, Taiwan
| | - Tien-Jyun Chang
- Department of Internal Medicine, National Taiwan University Hospital, 7 Chung-Shan South Road, Taipei 10002, Taiwan
- *Tien-Jyun Chang:
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24
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Jindal R, Ahmad A, Siddiqui MA, Kochar IS, Wangnoo SK. Novel mutation c.597_598dup in exon 5 of ABCC8 gene causing congenital hyperinsulinism. Diabetes Metab Syndr 2014; 8:45-47. [PMID: 24661758 DOI: 10.1016/j.dsx.2013.02.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Congenital hyperinsulinism (CHI), a clinically and genetically heterogeneous disease, characterized by the unregulated secretion of insulin from pancreatic β-cells, is the most common cause of persistent hypoglycemia in infancy. Early diagnosis and maintenance of normoglycaemia are essential to prevent adverse neurodevelopmental outcomes. The most common and severe forms of CHI are caused by inactivating mutations in ABCC8 and KCNJ11 genes, encoding the two subunits of the pancreatic β-cell ATP sensitive potassium channel (KATP). We report a case of neonatal CHI due to a novel homozygous recessive mutation in the ABCC8 gene.
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Affiliation(s)
- Radhika Jindal
- Department of Endocrinology, Indraprastha Apollo Hospital, Sarita Vihar, New Delhi, India.
| | - Ayesha Ahmad
- Department of Pediatrics, Indraprastha Apollo Hospital, Sarita Vihar, New Delhi, India
| | - Mohammad Asim Siddiqui
- Department of Endocrinology, Indraprastha Apollo Hospital, Sarita Vihar, New Delhi, India
| | - Inderpal Singh Kochar
- Department of Pediatrics, Indraprastha Apollo Hospital, Sarita Vihar, New Delhi, India
| | - Subhash Kumar Wangnoo
- Department of Endocrinology, Indraprastha Apollo Hospital, Sarita Vihar, New Delhi, India
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Martin GM, Chen PC, Devaraneni P, Shyng SL. Pharmacological rescue of trafficking-impaired ATP-sensitive potassium channels. Front Physiol 2013; 4:386. [PMID: 24399968 PMCID: PMC3870925 DOI: 10.3389/fphys.2013.00386] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/09/2013] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (KATP) 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, KATP 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 KATP 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, KATP 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 KATP 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.
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Affiliation(s)
- Gregory M Martin
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Pei-Chun Chen
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Prasanna Devaraneni
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
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Sherif EM, Abdelmaksoud AA, Elbarbary NS, Njølstad PR. An Egyptian case of congenital hyperinsulinism of infancy due to a novel mutation in KCNJ11 encoding Kir6.2 and response to octreotide. Acta Diabetol 2013; 50:801-5. [PMID: 20686794 DOI: 10.1007/s00592-010-0217-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Accepted: 07/26/2010] [Indexed: 11/24/2022]
Abstract
Congenital hyperinsulinism of infancy (CHI) is a rare heterogeneous disease mostly attributable to mutations in the genes encoding the KATP channel subunits found in pancreatic β-cells. Here, we report a child presenting at day 1 with persistent hyperinsulinemic hypoglycemia and who underwent open laparotomy and subtotal pancreatectomy with resection of tail and body of pancreas at 30 days of age. Normoglycemia was restored by Octreotide that was discontinued when the child was 7-month old. However, 3 months later Octreotide was re-administered as hypoglycemic attacks recurred. On follow-up, the child has adequate glycemic control and is thriving well with no neurodevelopmental morbidity. Genetic analysis revealed the novel mutation c.407G > A [p.R136H] in KCNJ11 encoding Kir6.2, confirming the diffuse form of CHI. This is to our knowledge the first reported Egyptian case of CHI due to a mutation in KCNJ11.
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Affiliation(s)
- Eman M Sherif
- Department of Pediatrics, Ain Shams University, Cairo, Egypt
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Snider KE, Becker S, Boyajian L, Shyng SL, MacMullen C, Hughes N, Ganapathy K, Bhatti T, Stanley CA, Ganguly A. Genotype and phenotype correlations in 417 children with congenital hyperinsulinism. J Clin Endocrinol Metab 2013; 98:E355-63. [PMID: 23275527 PMCID: PMC3565119 DOI: 10.1210/jc.2012-2169] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
CONTEXT Hypoglycemia due to congenital hyperinsulinism (HI) is caused by mutations in 9 genes. OBJECTIVE Our objective was to correlate genotype with phenotype in 417 children with HI. METHODS Mutation analysis was carried out for the ATP-sensitive potassium (KATP) channel genes (ABCC8 and KCNJ11), GLUD1, and GCK with supplemental screening of rarer genes, HADH, UCP2, HNF4A, HNF1A, and SLC16A1. RESULTS Mutations were identified in 91% (272 of 298) of diazoxide-unresponsive probands (ABCC8, KCNJ11, and GCK), and in 47% (56 of 118) of diazoxide-responsive probands (ABCC8, KCNJ11, GLUD1, HADH, UCP2, HNF4A, and HNF1A). In diazoxide-unresponsive diffuse probands, 89% (109 of 122) carried KATP mutations; 2% (2 of 122) had GCK mutations. In mutation-positive diazoxide-responsive probands, 42% were GLUD1, 41% were dominant KATP mutations, and 16% were in rare genes (HADH, UCP2, HNF4A, and HNF1A). Of the 183 unique KATP mutations, 70% were novel at the time of identification. Focal HI accounted for 53% (149 of 282) of diazoxide-unresponsive probands; monoallelic recessive KATP mutations were detectable in 97% (145 of 149) of these cases (maternal transmission excluded in all cases tested). The presence of a monoallelic recessive KATP mutation predicted focal HI with 97% sensitivity and 90% specificity. CONCLUSIONS Genotype to phenotype correlations were most successful in children with GLUD1, GCK, and recessive KATP mutations. Correlations were complicated by the high frequency of novel missense KATP mutations that were uncharacterized, because such defects might be either recessive or dominant and, if dominant, be either responsive or unresponsive to diazoxide. Accurate and timely prediction of phenotype based on genotype is critical to limit exposure to persistent hypoglycemia in infants and children with congenital HI.
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Affiliation(s)
- K E Snider
- Department of Genetics, University of Pennsylvania, 415 Anatomy Chemistry Building, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, USA
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Arnoux JB, Verkarre V, Saint-Martin C, Montravers F, Brassier A, Valayannopoulos V, Brunelle F, Fournet JC, Robert JJ, Aigrain Y, Bellanné-Chantelot C, de Lonlay P. Congenital hyperinsulinism: current trends in diagnosis and therapy. Orphanet J Rare Dis 2011; 6:63. [PMID: 21967988 PMCID: PMC3199232 DOI: 10.1186/1750-1172-6-63] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 10/03/2011] [Indexed: 01/25/2023] Open
Abstract
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.
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Affiliation(s)
- Jean-Baptiste Arnoux
- Centre de Référence des Maladies Héréditaires du Métabolisme de l'Enfant et l'Adulte, AP-HP Hôpital Necker-Enfants Malades, Université Paris Descartes, Paris, France
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El-sisi AE, Hegazy SK, Metwally SS, Wafa AM, Dawood NA. Effect of genetic polymorphisms on the development of secondary failure to sulfonylurea in egyptian patients with type 2 diabetes. Ther Adv Endocrinol Metab 2011; 2:155-64. [PMID: 23148181 PMCID: PMC3474636 DOI: 10.1177/2042018811415985] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE This study investigated the possibility that genetic factors, such as polymorphism of K inward rectifier subunit (Kir6.2), E23K, and Arg(972) polymorphism of insulin receptor sub-strate-1 (IRS-1), may predispose patients to sulfonylurea failure. METHODS A total of 100 unrelated Egyptian patients with type 2 diabetes were recruited. They were divided into two equal groups: group I consisted of patients with secondary failure to sulfonylurea (hemoglobin A(1c) ≥ 8% despite sulfonylurea therapy) while group II consisted of patients whose condition was controlled with oral therapy. RESULTS Of all the patients, 45% and 14% were carriers of the K allele and Arg(972) variants respectively. The frequency of the K allele was 34% among patients with diabetes that was controlled with oral therapy and 56% among patients with secondary failure to sulfonylurea. The frequency of the Arg(972) IRS-1 variant was 6% among patients with diabetes controlled with oral therapy and 22% among patients with secondary failure. CONCLUSION The E23K variant of the Kir6.2 gene and Arg(972) IRS-1 variants are associated with increased risk for secondary failure to sulfonylurea.
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Affiliation(s)
| | | | | | | | - Naglaa A. Dawood
- Specialized Internal Medicine Hospital, Mansoura University, Lecturer in clinical pharmacy dept., Pharmacy collage, King Khalid University, KSA
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MacMullen CM, Zhou Q, Snider KE, Tewson PH, Becker SA, Aziz AR, Ganguly A, Shyng SL, Stanley CA. Diazoxide-unresponsive congenital hyperinsulinism in children with dominant mutations of the β-cell sulfonylurea receptor SUR1. Diabetes 2011; 60:1797-804. [PMID: 21536946 PMCID: PMC3114386 DOI: 10.2337/db10-1631] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Congenital hyperinsulinemic hypoglycemia is a group of genetic disorders of insulin secretion most commonly associated with inactivating mutations of the β-cell ATP-sensitive K(+) channel (K(ATP) channel) genes ABCC8 (SUR1) and KCNJ11 (Kir6.2). Recessive mutations of these genes cause hyperinsulinism that is unresponsive to treatment with diazoxide, a channel agonist. Dominant K(ATP) mutations have been associated with diazoxide-responsive disease. We hypothesized that some medically uncontrollable cases with only one K(ATP) mutation might have dominant, diazoxide-unresponsive disease. RESEARCH DESIGN AND METHODS Mutations of the K(ATP) genes were identified by sequencing genomic DNA. Effects of mutations on K(ATP) channel function in vitro were studied by expression in COSm6 cells. RESULTS In 15 families with diazoxide-unresponsive diffuse hyperinsulism, we found 17 patients with a monoallelic missense mutation of SUR1. Nine probands had de novo mutations, two had an affected sibling or parent, and four had an asymptomatic carrier parent. Of the 13 different mutations, 12 were novel. Expression of mutations revealed normal trafficking of channels but severely impaired responses to diazoxide or MgADP. Responses were significantly lower compared with nine SUR1 mutations associated with dominant, diazoxide-responsive hyperinsulinism. CONCLUSIONS These results demonstrate that some dominant mutations of SUR1 can cause diazoxide-unresponsive hyperinsulinism. In vitro expression studies may be helpful in distinguishing such mutations from dominant mutations of SUR1 associated with diazoxide-responsive disease.
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Affiliation(s)
- Courtney M. MacMullen
- Division of Endocrinology/Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Qing Zhou
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - Kara E. Snider
- Division of Endocrinology/Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Paul H. Tewson
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - Susan A. Becker
- Division of Endocrinology/Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Ali Rahim Aziz
- Division of Endocrinology/Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Arupa Ganguly
- Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - Charles A. Stanley
- Division of Endocrinology/Diabetes, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Corresponding author: Charles A. Stanley,
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Liberatore Junior RDR, Martinelli Junior CE. [Hypoglycemia hypersinsulinemic of infancy]. ARQUIVOS BRASILEIROS DE ENDOCRINOLOGIA E METABOLOGIA 2011; 55:177-83. [PMID: 21655865 DOI: 10.1590/s0004-27302011000300001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2001] [Accepted: 04/18/2011] [Indexed: 11/21/2022]
Abstract
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.
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Affiliation(s)
- Raphael Del Roio Liberatore Junior
- Serviço de Endocrinologia Pediátrica, Departamento de Pediatria e Cirurgia Pediátrica, Faculdade de Medicina de São José do Rio Preto, SP, Brasil.
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Abstract
The use of mouse models in medical research has greatly contributed to our understanding of the development of type 2 diabetes mellitus and the mechanisms of disease progression in the context of insulin resistance and β-cell dysfunction. Maintenance of glucose homeostasis involves a complex interplay of many genes and their actions in response to exogenous stimuli. In recent years, the availability of large population-based cohorts and the capacity to genotype enormous numbers of common genetic variants have driven various large-scale genome-wide association studies, which has greatly accelerated the identification of novel genes likely to be involved in the development of type 2 diabetes. The increasing demand for verifying novel genes is met by the timely development of new mouse resources established as various collaborative projects involving major transgenic and phenotyping centres and laboratories worldwide. The surge of new data will ultimately enable translational research into potential improvement and refinement of current type 2 diabetes therapy options, and hopefully restore quality of life for patients.
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Hugill A, Shimomura K, Ashcroft FM, Cox RD. A mutation in KCNJ11 causing human hyperinsulinism (Y12X) results in a glucose-intolerant phenotype in the mouse. Diabetologia 2010; 53:2352-6. [PMID: 20694718 PMCID: PMC5894805 DOI: 10.1007/s00125-010-1866-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Accepted: 07/06/2010] [Indexed: 11/30/2022]
Abstract
AIMS/HYPOTHESIS We identified a mouse with a point mutation (Y12STOP) in the Kcnj11 subunit of the K(ATP) channel. This point mutation is identical to that found in a patient with congenital hyperinsulinism of infancy (HI). We aimed to characterise the phenotype arising from this loss-of-function mutation and to compare it with that of other mouse models and patients with HI. METHODS We phenotyped an N-ethyl-N-nitrosourea-induced mutation on a C3H/HeH background (Kcnj11 ( Y12STOP )) using intraperitoneal glucose tolerance testing to measure glucose and insulin plasma concentrations. Insulin secretion and response to incretins were measured on isolated islets. RESULTS Homozygous male and female adult Kcnj11 ( Y12STOP ) mice exhibited impaired glucose tolerance and a defect in insulin secretion as measured in vivo and in vitro. Islets had an impaired incretin response and reduced insulin content. CONCLUSIONS/INTERPRETATION The phenotype of homozygous Kcnj11 ( Y12STOP ) mice is consistent with that of other Kcnj11-knockout mouse models. In contrast to the patient carrying this mutation homozygously, the mice studied did not have hyperinsulinaemia or hypoglycaemia. It has been reported that HI patients may develop diabetes and our mouse model may reflect this clinical feature. The Kcnj11 ( Y12STOP ) model may thus be useful in further studies of K(ATP) channel function in various cell types and in investigation of the development of hyperglycaemia in HI patients.
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Affiliation(s)
- A Hugill
- Metabolism and Inflammation, MRC Harwell Mammalian Genetics Unit, Harwell Science and Innovation Campus, Harwell, OX11 0RD, UK
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Abstract
The pancreatic β-cell ATP-sensitive K(+) channel (K(ATP) channel) plays a critical role in glucose homeostasis by linking glucose metabolism to electrical excitability and insulin secretion. Changes in the intracellular ratio of ATP/ADP mediate the metabolic regulation of channel activity. The β-cell K(ATP) channel is a hetero-octameric complex composed of two types of subunits: four inward-rectifying potassium channel pore-forming (Kir6.2) subunits and four high-affinity sulfonylurea receptor 1 (SUR1) subunits. Kir6.2 and SUR1 are encoded by the genes KCNJ11 and ABCC8, respectively. Mutations in these genes can result in congenital hyperinsulinism and permanent neonatal diabetes. This review highlights the important role of the β-cell K(ATP) channel in glucose physiology and provides an introduction to some of the other review articles in this special edition of the Reviews in Endocrine and Metabolic Disorders.
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Affiliation(s)
- Kate Bennett
- Developmental Endocrinology Research Group, Clinical and Molecular Genetics Unit, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
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Lovisolo SM, Mendonça BB, Pinto EM, Manna TD, Saldiva PHN, Zerbini MCN. Congenital hyperinsulinism in Brazilian neonates: a study of histology, KATP channel genes, and proliferation of β cells. Pediatr Dev Pathol 2010; 13:375-84. [PMID: 20482375 DOI: 10.2350/08-12-0578.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Congenital hyperinsulinism (CHI) is a rare pancreatic β-cell disease of neonates, characterized by inappropriate insulin secretion with severe persistent hypoglycemia, with regard to which many questions remain to be answered, despite the important acquisition of its molecular mechanisms in the last decade. The aim of this study was to examine pancreatic histology, β-cell proliferation (immunohistochemistry with double staining for Ki-67/insulin), and β-cell adenosine triphosphate-sensitive potassium channels genes from 11 Brazilian patients with severe medically unresponsive CHI who underwent pancreatectomy. Pancreatic histology and β-cell proliferation in CHI patients were compared to pancreatic samples from 19 age-matched controls. Ten cases were classified as diffuse form (D-CHI) and 1 as focal form (F-CHI). β-cell nucleomegaly and abundant cytoplasm were absent in controls and were observed only in D-CHI patients. The Ki-67 labeling index (Ki-67-LI) was used to differentiate the adenomatous areas of the F-CHI case (10.15%) from the "loose cluster of islets" found in 2 D-CHI samples (2.29% and 2.43%) and 1 control (1.54%) sample. The Ki-67-LI was higher in the F-CHI adenomatous areas, but D-CHI patients also had significantly greater Ki-67-LI (mean value = 2.41%) than age-matched controls (mean value = 1.87%) (P = 0.009). In this 1st genetic study of CHI patients in Brazil, no mutations or new polymorphisms were found in the 33-37 exons of the ABCC8 gene (SUR1) or in the entire exon of the KCNJ11 gene (Kir 6.2) in 4 of 4 patients evaluated. On the other hand, enhanced β-cell proliferation seems to be a constant feature in CHI patients, both in diffuse and focal forms.
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Affiliation(s)
- Silvana M Lovisolo
- Department of Pathology, University of São Paulo Medical School, São Paulo, Brasil
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Abstract
Congenital hyperinsulinism is a leading cause of severe hypoglycaemia in the newborn period. There are two (diffuse and focal) histological subtypes of congenital hyperinsulinism. The diffuse form affects the entire pancreas and if medically unresponsive will require a near total (95%-98%) pancreatectomy. The focal form affects only a small region of the pancreas (with the rest of the pancreas being normal in endocrine and exocrine function) and only requires a limited pancreatectomy. This limited section of the focal lesion has the potential for curing the patient. Thus the pre-operative differentiation of these two subgroups is extremely important. Recent advances in Fluorine-18-L-dihydroxyphenylalanine positron emission tomography ((18)F-DOPA PET/CT) have radically changed the clinical approach to patient with congenital hyperinsulinism. In most patients this novel imaging technique is able to offer precise pre-operative localisation of the focal lesion, thus guiding the extent of surgical resection.
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Affiliation(s)
- Dunia Ismail
- Clinical and Molecular Genetics Unit, The Developmental Endocrinology Research Group, Institute of Child Health, University College London, Great Ormond Street Hospital for Children NHS Trust, 30 Guilford Street, London, WC1N 1EH, UK
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Abstract
A variety of treatment modalities exist for individuals with type 2 diabetes mellitus (T2D). In addition to dietary and physical activity interventions, T2D is also treated pharmacologically with nine major classes of approved drugs. These medications include insulin and its analogues, sulfonylureas, biguanides, thiazolidinediones (TZDs), meglitinides, α-glucosidase inhibitors, amylin analogues, incretin hormone mimetics, and dipeptidyl peptidase 4 (DPP4) inhibitors. Pharmacological treatment strategies for T2D are typically based on efficacy, yet favorable responses to such therapeutics are oftentimes variable and difficult to predict. Characterization of drug response is expected to substantially enhance our ability to provide patients with the most effective treatment strategy given their individual backgrounds, yet pharmacogenetic study of diabetes medications is still in its infancy. To date, major pharmacogenetic studies have focused on response to sulfonylureas, biguanides, and TZDs. Here, we provide a comprehensive review of pharmacogenetics investigations of these specific anti-diabetes medications. We focus not only on the results of these studies, but also on how experimental design, study sample issues, and definition of 'response' can significantly impact our interpretation of findings. Understanding the pharmacogenetics of anti-diabetes medications will provide critical baseline information for the development and implementation of genetic screening into therapeutic decision making, and lay the foundation for "individualized medicine" for patients with T2D.
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Affiliation(s)
- Johanna K. DiStefano
- Metabolic Diseases Division, Translational Genomics Research Institute, 445 N. 5th Street, Phoenix, AZ 85004, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-602-343-8812; Fax: +1-602-343-8844
| | - Richard M. Watanabe
- Departments of Preventive Medicine and Physiology & Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; E-Mail: (R.M.W.)
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Narayanaswamy V, Rettig KR, Bhowmick SK. A lethargic neonate and an infant with seizure. Clin Pediatr (Phila) 2010; 49:396-9. [PMID: 19380884 DOI: 10.1177/0009922809333100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Hibino H, Inanobe A, Furutani K, Murakami S, Findlay I, Kurachi Y. Inwardly rectifying potassium channels: their structure, function, and physiological roles. Physiol Rev 2010; 90:291-366. [PMID: 20086079 DOI: 10.1152/physrev.00021.2009] [Citation(s) in RCA: 1069] [Impact Index Per Article: 76.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Inwardly rectifying K(+) (Kir) channels allow K(+) to move more easily into rather than out of the cell. They have diverse physiological functions depending on their type and their location. There are seven Kir channel subfamilies that can be classified into four functional groups: classical Kir channels (Kir2.x) are constitutively active, G protein-gated Kir channels (Kir3.x) are regulated by G protein-coupled receptors, ATP-sensitive K(+) channels (Kir6.x) are tightly linked to cellular metabolism, and K(+) transport channels (Kir1.x, Kir4.x, Kir5.x, and Kir7.x). Inward rectification results from pore block by intracellular substances such as Mg(2+) and polyamines. Kir channel activity can be modulated by ions, phospholipids, and binding proteins. The basic building block of a Kir channel is made up of two transmembrane helices with cytoplasmic NH(2) and COOH termini and an extracellular loop which folds back to form the pore-lining ion selectivity filter. In vivo, functional Kir channels are composed of four such subunits which are either homo- or heterotetramers. Gene targeting and genetic analysis have linked Kir channel dysfunction to diverse pathologies. The crystal structure of different Kir channels is opening the way to understanding the structure-function relationships of this simple but diverse ion channel family.
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Affiliation(s)
- Hiroshi Hibino
- Department of Pharmacology, Graduate School of Medicine and The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka 565-0871, Japan
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Clark R, Proks P. ATP-sensitive potassium channels in health and disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 654:165-92. [PMID: 20217498 DOI: 10.1007/978-90-481-3271-3_8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ATP-sensitive potassium (K(ATP)) channel plays a crucial role in insulin secretion and thus glucose homeostasis. K(ATP) channel activity in the pancreatic beta-cell is finely balanced; increased activity prevents insulin secretion, whereas reduced activity stimulates insulin release. The beta-cell metabolism tightly regulates K(ATP) channel gating, and if this coupling is perturbed, two distinct disease states can result. Diabetes occurs when the K(ATP) channel fails to close in response to increased metabolism, whereas congenital hyperinsulinism results when K(ATP) channels remain closed even at very low blood glucose levels. In general there is a good correlation between the magnitude of K(ATP) current and disease severity. Mutations that cause a complete loss of K(ATP) channels in the beta-cell plasma membrane produce a severe form of congenital hyperinsulinism, whereas mutations that partially impair channel function produce a milder phenotype. Similarly mutations that greatly reduce the ATP sensitivity of the K(ATP) channel lead to a severe form of neonatal diabetes with associated neurological complications, whilst mutations that cause smaller shifts in ATP sensitivity cause neonatal diabetes alone. This chapter reviews our current understanding of the pancreatic beta-cell K(ATP) channel and highlights recent structural, functional and clinical advances.
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Affiliation(s)
- Rebecca Clark
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
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Zhou M, He HJ, Hirano M, Sekiguchi M, Tanaka O, Kawahara K, Abe H. Localization of ATP-sensitive K+ channel subunits in rat submandibular gland. J Histochem Cytochem 2009; 58:499-507. [PMID: 19934381 DOI: 10.1369/jhc.2009.955047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ATP-sensitive K(+) (K(ATP)) channel subunits were investigated in rat submandibular gland (SMG). RT-PCR detected the presence of mRNA transcripts of the Kir6.1, Kir6.2, SUR2A, and SUR2B in the SMG, whereas SUR1 mRNA was barely detected. Western blot analysis provided the evidence that these four K(ATP) channel subunits are expressed in rat SMG. Immunostaining detected that these four K(ATP) channel subunits are widely distributed, with different intensities, in myoepithelial cells, epithelial cells of intercalated ducts, granular convoluted tubules, striated ducts, and excretory ducts. Immunofluorescence double staining showed that Kir6.1 and Kir6.2 colocalized with SUR2A in the myoepithelial cells, granular convoluted tubules, striated ducts, and excretory ducts. Kir6.1 and Kir6.2 also colocalized with SUR2B, mainly in the duct system, e.g., the granular convoluted tubules, striated ducts, and excretory ducts. Taken together, these results indicate that the K(ATP) channels in SMG may consist of Kir6.1, Kir6.2, SUR2A, and SUR2B, with various combinations of colocalization with each other, and may play important roles in rat SMG during salivary secretion.
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Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine and Faculty of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
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Sayed S, Langdon DR, Odili S, Chen P, Buettger C, Schiffman AB, Suchi M, Taub R, Grimsby J, Matschinsky FM, Stanley CA. Extremes of clinical and enzymatic phenotypes in children with hyperinsulinism caused by glucokinase activating mutations. Diabetes 2009; 58:1419-27. [PMID: 19336674 PMCID: PMC2682682 DOI: 10.2337/db08-1792] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
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.
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Affiliation(s)
- Samir Sayed
- Clinical Translational Research Center, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - David R. Langdon
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Stella Odili
- Diabetes and Endocrinology Research Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Pan Chen
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Carol Buettger
- Diabetes and Endocrinology Research Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Alisa B. Schiffman
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Mariko Suchi
- Department of Pathology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Pathology, Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Rebecca Taub
- Department of Metabolic Diseases, Roche, Nutley, New Jersey
| | - Joseph Grimsby
- Department of Metabolic Diseases, Roche, Nutley, New Jersey
| | - Franz M. Matschinsky
- Diabetes and Endocrinology Research Center, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Department of Biochemistry and Biophysics, the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - Charles A. Stanley
- Clinical Translational Research Center, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Corresponding author: Charles A. Stanley,
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Flanagan SE, Clauin S, Bellanné-Chantelot C, de Lonlay P, Harries LW, Gloyn AL, Ellard S. Update of mutations in the genes encoding the pancreatic beta-cell K(ATP) channel subunits Kir6.2 (KCNJ11) and sulfonylurea receptor 1 (ABCC8) in diabetes mellitus and hyperinsulinism. Hum Mutat 2009; 30:170-80. [PMID: 18767144 DOI: 10.1002/humu.20838] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The beta-cell ATP-sensitive potassium (K(ATP)) channel is a key component of stimulus-secretion coupling in the pancreatic beta-cell. The channel couples metabolism to membrane electrical events bringing about insulin secretion. Given the critical role of this channel in glucose homeostasis it is therefore not surprising that mutations in the genes encoding for the two essential subunits of the channel can result in both hypo- and hyperglycemia. The channel consists of four subunits of the inwardly rectifying potassium channel Kir6.2 and four subunits of the sulfonylurea receptor 1 (SUR1). It has been known for some time that loss of function mutations in KCNJ11, which encodes for Kir6.2, and ABCC8, which encodes for SUR1, can cause oversecretion of insulin and result in hyperinsulinism of infancy, while activating mutations in KCNJ11 and ABCC8 have recently been described that result in the opposite phenotype of diabetes. This review focuses on reported mutations in both genes, the spectrum of phenotypes, and the implications for treatment on diagnosing patients with mutations in these genes.
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Affiliation(s)
- Sarah E Flanagan
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, United Kingdom
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Mutations in UCP2 in congenital hyperinsulinism reveal a role for regulation of insulin secretion. PLoS One 2008; 3:e3850. [PMID: 19065272 PMCID: PMC2588657 DOI: 10.1371/journal.pone.0003850] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 11/10/2008] [Indexed: 12/21/2022] Open
Abstract
Although the most common mechanism underlying congenital hyperinsulinism is dysfunction of the pancreatic ATP-sensitive potassium channel, the pathogenesis and genetic origins of this disease remains largely unexplained in more than half of all patients. UCP2 knockout mice exhibit an hyperinsulinemic hypoglycemia, suggesting an involment of UCP2 in insulin secretion. However, a possible pathogenic role for UCP2 protein in the development of human congenital hyperinsulinism or of any human disease has not yet been investigated. We studied ten children exhibiting congenital hyperinsulinism, without detectable mutations in the known congenital hyperinsulinism-causing genes. Parental-inherited heterozygous UCP2 variants encoding amino-acid changes were found in two unrelated children with congenital hyperinsulinism. Functional assays in yeast and in insulin-secreting cells revealed an impaired activity of UCP2 mutants. Therefore, we report the finding of UCP2 coding variants in human congenital hyperinsulinism, which reveals a role for this gene in the regulation of insulin secretion and glucose metabolism in humans. Our results show for the first time a direct association between UCP2 amino acid alteration and human disease and highlight a role for mitochondria in hormone secretion.
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Remedi MS, Nichols CG. Chronic antidiabetic sulfonylureas in vivo: reversible effects on mouse pancreatic beta-cells. PLoS Med 2008; 5:e206. [PMID: 18959471 PMCID: PMC2573909 DOI: 10.1371/journal.pmed.0050206] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 09/09/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Pancreatic beta-cell ATP-sensitive potassium (K ATP) channels are critical links between nutrient metabolism and insulin secretion. In humans, reduced or absent beta-cell K ATP channel activity resulting from loss-of-function K ATP mutations induces insulin hypersecretion. Mice with reduced K ATP channel activity also demonstrate hyperinsulinism, but mice with complete loss of K ATP channels (K ATP knockout mice) show an unexpected insulin undersecretory phenotype. Therefore we have proposed an "inverse U" hypothesis to explain the response to enhanced excitability, in which excessive hyperexcitability drives beta-cells to insulin secretory failure without cell death. Many patients with type 2 diabetes treated with antidiabetic sulfonylureas (which inhibit K ATP activity and thereby enhance insulin secretion) show long-term insulin secretory failure, which we further suggest might reflect a similar progression. METHODS AND FINDINGS To test the above hypotheses, and to mechanistically investigate the consequences of prolonged hyperexcitability in vivo, we used a novel approach of implanting mice with slow-release sulfonylurea (glibenclamide) pellets, to chronically inhibit beta-cell K ATP channels. Glibenclamide-implanted wild-type mice became progressively and consistently diabetic, with significantly (p < 0.05) reduced insulin secretion in response to glucose. After 1 wk of treatment, these mice were as glucose intolerant as adult K ATP knockout mice, and reduction of secretory capacity in freshly isolated islets from implanted animals was as significant (p < 0.05) as those from K ATP knockout animals. However, secretory capacity was fully restored in islets from sulfonylurea-treated mice within hours of drug washout and in vivo within 1 mo after glibenclamide treatment was terminated. Pancreatic immunostaining showed normal islet size and alpha-/beta-cell distribution within the islet, and TUNEL staining showed no evidence of apoptosis. CONCLUSIONS These results demonstrate that chronic glibenclamide treatment in vivo causes loss of insulin secretory capacity due to beta-cell hyperexcitability, but also reveal rapid reversibility of this secretory failure, arguing against beta-cell apoptosis or other cell death induced by sulfonylureas. These in vivo studies may help to explain why patients with type 2 diabetes can show long-term secondary failure to secrete insulin in response to sulfonylureas, but experience restoration of insulin secretion after a drug resting period, without permanent damage to beta-cells. This finding suggests that novel treatment regimens may succeed in prolonging pharmacological therapies in susceptible individuals.
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Pinney SE, MacMullen C, Becker S, Lin YW, Hanna C, Thornton P, Ganguly A, Shyng SL, Stanley CA. Clinical characteristics and biochemical mechanisms of congenital hyperinsulinism associated with dominant KATP channel mutations. J Clin Invest 2008; 118:2877-86. [PMID: 18596924 DOI: 10.1172/jci35414] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 05/19/2008] [Indexed: 11/17/2022] Open
Abstract
Congenital hyperinsulinism is a condition of dysregulated insulin secretion often caused by inactivating mutations of the ATP-sensitive K+ (KATP) channel in the pancreatic beta cell. Though most disease-causing mutations of the 2 genes encoding KATP subunits, ABCC8 (SUR1) and KCNJ11 (Kir6.2), are recessively inherited, some cases of dominantly inherited inactivating mutations have been reported. To better understand the differences between dominantly and recessively inherited inactivating KATP mutations, we have identified and characterized 16 families with 14 different dominantly inherited KATP mutations, including a total of 33 affected individuals. The 16 probands presented with hypoglycemia at ages from birth to 3.3 years, and 15 of 16 were well controlled on diazoxide, a KATP channel agonist. Of 29 adults with mutations, 14 were asymptomatic. In contrast to a previous report of increased diabetes risk in dominant KATP hyperinsulinism, only 4 of 29 adults had diabetes. Unlike recessive mutations, dominantly inherited KATP mutant subunits trafficked normally to the plasma membrane when expressed in COSm6 cells. Dominant mutations also resulted in different channel-gating defects, as dominant ABCC8 mutations diminished channel responses to magnesium adenosine diphosphate or diazoxide, while dominant KCNJ11 mutations impaired channel opening, even in the absence of nucleotides. These data highlight distinctive features of dominant KATP hyperinsulinism relative to the more common and more severe recessive form, including retention of normal subunit trafficking, impaired channel activity, and a milder hypoglycemia phenotype that may escape detection in infancy and is often responsive to diazoxide medical therapy, without the need for surgical pancreatectomy.
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Affiliation(s)
- Sara E Pinney
- Division of Endocrinology/Diabetes, The Children's Hospital of Philadelphia, Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Alsmadi O, Al-Rubeaan K, Wakil SM, Imtiaz F, Mohamed G, Al-Saud H, Al-Saud NA, Aldaghri N, Mohammad S, Meyer BF. Genetic study of Saudi diabetes (GSSD): significant association of the KCNJ11 E23K polymorphism with type 2 diabetes. Diabetes Metab Res Rev 2008; 24:137-40. [PMID: 17922473 DOI: 10.1002/dmrr.777] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND The E23K variant of KCNJ11 has been associated with type 2 diabetes (T2D) in several but not all populations studied. Thus far, despite a high incidence of T2D, the role of this variant in Arabs has not been established. METHODS We performed a case-control association study using 550 T2D Saudi patients (WHO criteria), and 335 controls (age>or=60; fasting plasma glucose<7 mmol/L). E23K genotyping was performed by using molecular beacon-based real time PCR assays. RESULTS The difference in K or risk allele frequency of cases and controls was significant with an OR of 1.7 (p=0.0001). The K allele is more common among T2D patients (21%) than in the age and sex matched controls (13.6%). This was consistent with a likely eventual conversion to T2D of younger normoglycemic individuals as they grow older. CONCLUSIONS Our results report for the first time a positive association of the E23K variant with T2D in an Arab population. Confirmation by a larger study is indicated.
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Affiliation(s)
- Osama Alsmadi
- Arabian Diagnostic Laboratory (ADL), Research Centre, King Faisal Specialist Hospital and Research Centre, and Diabetes Center, King Abdulaziz University Hospital, Riyadh, Saudi Arabia.
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Patch AM, Flanagan SE, Boustred C, Hattersley AT, Ellard S. Mutations in the ABCC8 gene encoding the SUR1 subunit of the KATP channel cause transient neonatal diabetes, permanent neonatal diabetes or permanent diabetes diagnosed outside the neonatal period. Diabetes Obes Metab 2007; 9 Suppl 2:28-39. [PMID: 17919176 PMCID: PMC7611803 DOI: 10.1111/j.1463-1326.2007.00772.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AIM Mutations in the ABCC8 gene encoding the SUR1 subunit of the pancreatic ATP-sensitive potassium channel cause permanent neonatal diabetes mellitus (PNDM) and transient neonatal diabetes mellitus (TNDM). We reviewed the existing literature, extended the number of cases and explored genotype-phenotype correlations. METHODS Mutations were identified by sequencing in patients diagnosed with diabetes before 6 months without a KCNJ11 mutation. RESULTS We identified ABCC8 mutations in an additional nine probands (including five novel mutations L135P, R306H, R1314H, L438F and M1290V), bringing the total of reported families to 48. Both dominant and recessive mutations were observed with recessive inheritance more common in PNDM than TNDM (9 vs. 1; p < 0.01). The remainder of the PNDM probands (n = 12) had de novo mutations. Seventeen of twenty-five children with TNDM inherited their heterozygous mutation from a parent. Nine of these parents had permanent diabetes (median age at diagnosis: 27.5 years, range: 13-35 years). Recurrent mutations of residues R1183 and R1380 were found only in TNDM probands and dominant mutations causing PNDM clustered within exons 2-5. CONCLUSIONS ABCC8 mutations cause PNDM, TNDM or permanent diabetes diagnosed outside the neonatal period. There is some evidence that the location of the mutation is correlated with the clinical phenotype.
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Affiliation(s)
- A M Patch
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Exeter, UK
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Abstract
Nutrient oxidation in beta cells generates a rise in [ATP]:[ADP] ratio. This reduces K(ATP) channel activity, leading to depolarization, activation of voltage-dependent Ca(2+) channels, Ca(2+) entry and insulin secretion. Consistent with this paradigm, loss-of-function mutations in the genes (KCNJ11 and ABCC8) that encode the two subunits (Kir6.2 and SUR1, respectively) of the ATP-sensitive K(+) (K(ATP)) channel underlie hyperinsulinism in humans, a genetic disorder characterized by dysregulated insulin secretion. In mice with genetic suppression of K(ATP) channel subunit expression, partial loss of K(ATP) channel conductance also causes hypersecretion, but unexpectedly, complete loss results in an undersecreting, mildly glucose-intolerant phenotype. When challenged by a high-fat diet, normal mice and mice with reduced K(ATP) channel density respond with hypersecretion, but mice with more significant or complete loss of K(ATP) channels cross over, or progress further, to an undersecreting, diabetic phenotype. It is our contention that in mice, and perhaps in humans, there is an inverse U-shaped response to hyperexcitabilty, leading first to hypersecretion but with further exacerbation to undersecretion and diabetes. The causes of the overcompensation and diabetic susceptibility are poorly understood but may have broader implications for the progression of hyperinsulinism and type 2 diabetes in humans.
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Affiliation(s)
- C G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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