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Larsen AR, Brusgaard K, Christesen HT, Detlefsen S. Genotype-histotype-phenotype correlations in hyperinsulinemic hypoglycemia. Histol Histopathol 2024; 39:817-844. [PMID: 38305063 DOI: 10.14670/hh-18-709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Hyperinsulinemic hypoglycemia (HH) of pancreatic origin includes congenital hyperinsulinism (CHI), insulinoma, insulinomatosis, and adult-onset non-insulinoma persistent hyperinsulinemic hypoglycemia syndrome (NI-PHHS). In this review, we describe the genotype-histotype-phenotype correlations in HH and their therapeutic implications. CHI can occur from birth or later on in life. Histologically, diffuse CHI shows diffuse beta cell hypertrophy with a few giant nuclei per islet of Langerhans, most frequently caused by loss-of-function mutations in ABCC8 or KCNJ11. Focal CHI is histologically characterized by focal adenomatous hyperplasia consisting of confluent hyperplastic islets, caused by a paternal ABCC8/KCNJ11 mutation combined with paternal uniparental disomy of 11p15. CHI in Beckwith-Wiedemann syndrome is caused by mosaic changes in the imprinting region 11p15.4-11p15.5, leading to segmental or diffuse overgrowth of endocrine tissue in the pancreas. Morphological mosaicism of pancreatic islets is characterized by occurence of hyperplastic (type 1) islets in one or a few lobules and small (type 2) islets in the entire pancreas. Other rare genetic causes of CHI show less characteristic or unspecific histology. HH with a predominant adult onset includes insulinomas, which are pancreatic insulin-producing endocrine neoplasms, in some cases with metastatic potential. Insulinomas occur sporadically or as part of multiple endocrine neoplasia type 1 due to MEN1 mutations. MAFA mutations may histologically lead to insulinomatosis with insulin-producing neuroendocrine microadenomas or neuroendocrine neoplasms. NI-PHHS is mainly seen in adults and shows slight histological changes in some patients, which have been defined as major and minor criteria. The genetic cause is unknown in most cases. The diagnosis of HH, as defined by genetic, histological, and phenotypic features, has important implications for patient management and outcome.
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Affiliation(s)
- Annette Rønholt Larsen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
- Steno Diabetes Center, Odense University Hospital, Odense, Denmark
| | - Klaus Brusgaard
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
- Steno Diabetes Center, Odense University Hospital, Odense, Denmark
| | - Henrik Thybo Christesen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Steno Diabetes Center, Odense University Hospital, Odense, Denmark
| | - Sönke Detlefsen
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
- Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
- Department of Pathology, Odense University Hospital, Odense, Denmark.
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Demiral M, Çelebi H, Cander S, Yerci O, Eren E, Demirbilek H. TWO OPPOSITE PHENOTYPES OF GLUCOSE DISORDERS IN A FAMILY WITH HETEROZYGOUS P.SER453LEU (C.1358C> T) MUTATION IN THE GLUCOKINASE (GCK) GENE: MATURITY ONSET DIABETES IN YOUNG AND INSULINOMA. ACTA ENDOCRINOLOGICA (BUCHAREST, ROMANIA : 2005) 2022; 18:458-465. [PMID: 37152879 PMCID: PMC10162830 DOI: 10.4183/aeb.2022.458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Background Heterozygous gain-of-function mutations in the glucokinase (GCK) gene cause hyperinsulinaemic hypoglycaemia (GCK-HI), while loss-of-function mutations lead to a monogenic type of diabetes (GCK-MODY). We, herein, report a heterozygous GCK gene mutation in a large family with GCK-MODY and insulinoma in one individual from the same family. Patients and methods The proband, an 11-year-old male, was referred for asymptomatic mild hyperglycemia (fasting glucose:121 mg/dL) and HbA1c of 6.1%. Segregation analysis of the family revealed multiplex members with asymptomatic fasting hyperglycaemia or non-insulin-dependent diabetes and 33-year-old maternal uncle of the proband case had a history of distal pancreatectomy due to the diagnosis of insulinoma. His preoperative investigations were revealed fasting glucose of 31 mg/dL, insulin: 7µU/mL, C-peptide: 2.6 mg/dL, and a low HbA1c(4.0%) which was suggestive for recurring hypoglycaemia episodes. Post-pancreatectomy he developed mild fasting hyperglycemia (115-136 mg/dL). Results Genetic analysis revealed heterozygous p.Ser453Leu(c.1358C> T) mutation in the GCK gene in the proband. In segregation analysis, the identical heterozygous p.Ser453Leu(c.1358C> T) GCK gene mutation was detected in all of the other affected family members for whom a DNA analysis was applicable. The maternal uncle was first diagnosed with insulinoma and underwent a pancreatectomy. He also had an identical mutation in a heterozygous state. Conclusion We, to the best of our knowledge, firstly identified these two entirely distinct phenotypes of glucose metabolism, GCK-MODY and GCK-HI, due to an identical heterozygous p.Ser453Leu (c.1358C> T) mutation in the GCK. Further studies required to elucidate this new phenomenon and understanding the genotype-phenotype relationship of GCK gene mutations.
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Affiliation(s)
- M. Demiral
- Balıkesir Atatürk City Hospital, Department of Paediatric Endocrinology, Balıkesir
| | - H.B.G. Çelebi
- Balıkesir Atatürk City Hospital, Department of Medical Genetic, Balıkesir
| | - S. Cander
- Uludağ University, Department of Endocrinology, Bursa
| | - O. Yerci
- Uludağ University, Department of Pathology, Bursa
| | - E. Eren
- Uludağ University, Department of Paediatric Endocrinology, Bursa
| | - H. Demirbilek
- Hacettepe University, Faculty of Medicine, Department of Paediatric Endocrinology, Ankara, Turkey
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Langer S, Waterstradt R, Hillebrand G, Santer R, Baltrusch S. The novel GCK variant p.Val455Leu associated with hyperinsulinism is susceptible to allosteric activation and is conducive to weight gain and the development of diabetes. Diabetologia 2021; 64:2687-2700. [PMID: 34532767 PMCID: PMC8563668 DOI: 10.1007/s00125-021-05553-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/21/2021] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS The mammalian enzyme glucokinase (GK), expressed predominantly in liver and pancreas, plays an essential role in carbohydrate metabolism. Monogenic GK disorders emphasise the role of GK in determining the blood glucose set point. METHODS A family with congenital hyperinsulinism (CHI) was examined for GCK gene variants by Sanger sequencing. A combined approach, involving kinetic analysis (also using GK activators and inhibitors), intracellular translocation assays, insulin secretion measurements and structural modelling, was used to investigate the novel variant compared with known variants. RESULTS We report on the novel gain-of-function GCK variant p.Val455Leu (V455L), inherited as an autosomal dominant trait in a German family with CHI and concomitant obesity (fasting blood glucose 2.1 mmol/l, BMI 45.0 kg/m2, HOMA-IR 1.5 in an adult female family member); one male family member developed type 2 diabetes until age 35 years (with fasting glucose 2.8-3.7 mmol/l, BMI 38.9 kg/m2, HOMA-IR 4.6). Kinetic characterisation of the V455L variant revealed a significant increase in glucose affinity (glucose concentration at which reaction rate is half its maximum rate [S0.5]: mutant 2.4 ± 0.3 mmol/l vs wild-type 7.6 ± 1.0 mmol/l), accompanied by a distinct additive susceptibility to both the endogenous activator fructose 2,6-bisphosphatase and the synthetic allosteric activator RO-28-1675. The effect of RO-28-1675 was more pronounced when compared with the previously known GK variants V455M and V455E. Binding to the inhibitor glucokinase regulatory protein was unimpaired for V455L and V455E but was reduced for V455M, whereas mannoheptulose inhibited all GK variants and the wild-type enzyme. Structural analyses suggested a role for residue 455 in rearrangements between the inactive and active conformations of GK and also in allosteric activation. Comparison with V455M and V455E and an overview of activating GK variants provided a context for the novel sequence aberration in terms of altered GK enzyme characteristics caused by single amino acid changes. CONCLUSION/INTERPRETATION We provide new knowledge on the structure-function relationship of GK, with special emphasis on enzyme activation, potentially yielding fresh strategic insights into breaking the vicious circle of fluctuating blood glucose levels and the attendant risk of long-lasting metabolic changes in both CHI and type 2 diabetes.
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Affiliation(s)
- Sara Langer
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Rostock, Rostock, Germany
| | - Rica Waterstradt
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Rostock, Rostock, Germany
| | - Georg Hillebrand
- Department of Pediatrics, University Medical Center Eppendorf, Hamburg, Germany
- Department of Pediatrics, Medical Center Itzehoe, Itzehoe, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Eppendorf, Hamburg, Germany
| | - Simone Baltrusch
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Rostock, Rostock, Germany.
- Department Life, Light & Matter, University of Rostock, Rostock, Germany.
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Attie AD, Tang QQ, Bornfeldt KE. The insulin centennial-100 years of milestones in biochemistry. J Biol Chem 2021; 297:101278. [PMID: 34717954 PMCID: PMC8605089 DOI: 10.1016/j.jbc.2021.101278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2021] [Indexed: 11/21/2022] Open
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Attie AD, Tang QQ, Bornfeldt KE. The insulin centennial-100 years of milestones in biochemistry. J Lipid Res 2021; 62:100132. [PMID: 34717951 PMCID: PMC8721491 DOI: 10.1016/j.jlr.2021.100132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2021] [Indexed: 11/05/2022] Open
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Hyperinsulinemic Hypoglycemia in Three Generations of a Family with Glucokinase Activating Mutation, c.295T>C (p.Trp99Arg). Genes (Basel) 2021; 12:genes12101566. [PMID: 34680961 PMCID: PMC8535713 DOI: 10.3390/genes12101566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/26/2022] Open
Abstract
Familial Hyperinsulinemic Hypoglycemia (FHH) is a very rare disease with heterogeneous clinical manifestations. There are only a few reports of heterozygous activating mutations of glucokinase (GCK) attributable to FHH, with no reports describing effects in the course in pregnancy with affected mother/affected child. A large kindred with FHH and GCK:c.295T>C (p.Trp99Arg) pathogenic variant was identified in which four family members from three generations were affected. The clinical follow up in one clinical center lasted up to 30 years, with different times of diagnosis ranging from neonate period to adulthood. The severity of hypoglycemia was mild/severe and fasting was the trigger for hypoglycemia. Response to diazoxide varied from good, in the neonate, to moderate/poor, in childhood/adulthood; however, this was biased by poor compliance. Treatment with somatostatin analogues was discontinued due to side effects. Over time, patients developed clinical adaptation to very low glucose levels. During pregnancy, episodes of severe hypoglycemia in the first trimester were observed, which responded very well to steroids. The clinical course of the GCK:c.295T>C (p.Trp99Arg) mutation varied in the same family, with the development of clinical adaptation to very low glucose levels over time. Treatment with steroids might prevent hypoglycemia during pregnancy in an affected mother.
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Sanchez Caballero L, Gorgogietas V, Arroyo MN, Igoillo-Esteve M. Molecular mechanisms of β-cell dysfunction and death in monogenic forms of diabetes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:139-256. [PMID: 33832649 DOI: 10.1016/bs.ircmb.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monogenetic forms of diabetes represent 1%-5% of all diabetes cases and are caused by mutations in a single gene. These mutations, that affect genes involved in pancreatic β-cell development, function and survival, or insulin regulation, may be dominant or recessive, inherited or de novo. Most patients with monogenic diabetes are very commonly misdiagnosed as having type 1 or type 2 diabetes. The severity of their symptoms depends on the nature of the mutation, the function of the affected gene and, in some cases, the influence of additional genetic or environmental factors that modulate severity and penetrance. In some patients, diabetes is accompanied by other syndromic features such as deafness, blindness, microcephaly, liver and intestinal defects, among others. The age of diabetes onset may also vary from neonatal until early adulthood manifestations. Since the different mutations result in diverse clinical presentations, patients usually need different treatments that range from just diet and exercise, to the requirement of exogenous insulin or other hypoglycemic drugs, e.g., sulfonylureas or glucagon-like peptide 1 analogs to control their glycemia. As a consequence, awareness and correct diagnosis are crucial for the proper management and treatment of monogenic diabetes patients. In this chapter, we describe mutations causing different monogenic forms of diabetes associated with inadequate pancreas development or impaired β-cell function and survival, and discuss the molecular mechanisms involved in β-cell demise.
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Affiliation(s)
- Laura Sanchez Caballero
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Vyron Gorgogietas
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Maria Nicol Arroyo
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/.
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Liang H, Zhang Y, Li M, Yan J, Yang D, Luo S, Zheng X, Yang G, Li Z, Xu W, Groop L, Weng J. Recognition of maturity-onset diabetes of the young in China. J Diabetes Investig 2020; 12:501-509. [PMID: 32741144 PMCID: PMC8015824 DOI: 10.1111/jdi.13378] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/14/2022] Open
Abstract
Aims/Introduction Given that mutations related to maturity‐onset diabetes of the young (MODY) are rarely found in Chinese populations, we aim to characterize the mutation spectrum of MODY pedigrees. Materials and Methods Maturity‐onset diabetes of the young candidate gene‐ or exome‐targeted capture sequencing was carried out in 76 probands from unrelated families fulfilling the clinical diagnostic criteria for MODY. MAF <0.01 in the GnomAD or ExAC database was used to filter significant variants. Sanger sequencing was then carried out to validate findings. Function prediction by SIFT, PolyPhen‐2 and PROVEAN or CADD was carried out in missense mutations. Results A total of 32 mutations in six genes were identified in 31 families, accounting for 40.79% of the potential MODY families. The MODY subtype detection rate was 18.42% for GCK, 15.79% for HNF1A, 2.63% for HNF4A, and 1.32% for KLF11, PAX4 and NEUROG3. Seven nonsense/frameshift mutations and four missense mutations with damaging prediction were newly identified novel mutations. The clinical features of MODY2, MODY3/1 and MODYX are similar to previous reports. Clinical phenotype of NEUROG3 p.Arg55Glufs*23 is characterized by hyperglycemia and mild intermittent abdominal pain. Conclusions This study adds to the emerging pattern of MODY epidemiology that the proportion of MODY explained by known pathogenic genes is higher than that previously reported, and found NEUROG3 as a new causative gene for MODY.
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Affiliation(s)
- Hua Liang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Yanan Zhang
- Department of Infertility and Sexual Medicine, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Maixinyue Li
- Department of Clinical Laboratory, Nanning Children's Hospital, Nanning, China
| | - Jinhua Yan
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Daizhi Yang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Sihui Luo
- Division of Life Sciences and Medicine, Department of Endocrinology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, China
| | - Xueying Zheng
- Division of Life Sciences and Medicine, Department of Endocrinology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, China
| | - Guoqing Yang
- Department of Endocrinology, Chinese PLA General Hospital, Beijing, China
| | - Zhuo Li
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Wen Xu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China
| | - Leif Groop
- Department of Clinical Sciences, Lund University Diabetes Center, Lund University, Malmö, Sweden
| | - Jianping Weng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China.,Division of Life Sciences and Medicine, Department of Endocrinology, The First Affiliated Hospital, University of Science and Technology of China, Hefei, China
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Ping F, Wang Z, Xiao X. Clinical and enzymatic phenotypes in congenital hyperinsulinemic hypoglycemia due to glucokinase-activating mutations: A report of two cases and a brief overview of the literature. J Diabetes Investig 2019; 10:1454-1462. [PMID: 31094068 PMCID: PMC6825936 DOI: 10.1111/jdi.13072] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 04/10/2019] [Accepted: 04/26/2019] [Indexed: 01/06/2023] Open
Abstract
AIMS/INTRODUCTION The principal aim of this study was to investigate the clinical, genetic and functional characteristics of two cases of congenital hyperinsulinism (CHI) caused by glucokinase (GCK) mutations in young patients. MATERIALS AND METHODS Novel mutations were detected by CHI next-generation sequencing, and the kinetic parameters and thermal stability of recombinant wild-type and mutant glucokinase were determined in vitro. In addition, 18 naturally occurring GCK-CHI mutations reported previously were also summarized. RESULTS A de novo mutation (M197V) was found in a 17-year-old male with an epilepsy history, whereas an autosomal dominant mutation (K90R) was found in a 20-year-old female with inherited asymptomatic hypoglycemia. Kinetic analysis showed increased enzyme activity for both mutants (RAI 4.7 for M197V and 1.6 for K90R) and enhanced thermal stability for the M197V mutant. However, of all the GCK-CHI mutants, the increase in enzyme activity (RAI between 1.6 and 130) did not correlate strongly with the severity of hypoglycemia. The de novo group (7/19) showed distinctive phenotypes from the autosomal dominant group (12/19), such as a higher proportion of diazoxide unresponsiveness (28.6% vs 0%), a higher incidence of macrosomia (85.7% vs 40%) and a rarer incidence of adulthood onset (0% vs 25%). CONCLUSIONS The clinical phenotypes of GCK-CHIs were highly heterogeneous. We have identified two novel GCK-CHI mutations in young patients and investigated their pathogenicity by enzyme kinetic analysis, which expanded the spectrum of this rare disease.
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Affiliation(s)
- Fan Ping
- NHC Key Laboratory of EndocrinologyDepartment of EndocrinologyPeking Union Medical College HospitalChinese Academy of Medical Science and Peking UnionBeijingChina
| | - Zhixin Wang
- Department of EndocrinologyBeijing Jishuitan HospitalBeijingChina
| | - Xinhua Xiao
- NHC Key Laboratory of EndocrinologyDepartment of EndocrinologyPeking Union Medical College HospitalChinese Academy of Medical Science and Peking UnionBeijingChina
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Lu B, Tonne JM, Munoz-Gomez M, Ikeda Y. Hyperinsulinemic hypoglycemia subtype glucokinase V91L mutant induces necrosis in β-cells via ATP depletion. Biochem Biophys Rep 2019; 17:108-113. [PMID: 30623114 PMCID: PMC6304456 DOI: 10.1016/j.bbrep.2018.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/09/2018] [Accepted: 12/06/2018] [Indexed: 12/24/2022] Open
Abstract
Hyperinsulinemic hypoglycemia subtype glucokinase (GCK-HH) is caused by an activating mutation in glucokinase (GCK) and has been shown to increase β-cell death. However, the mechanism of β-cell death in GCK-HH remains poorly understood. Here, we expressed the GCK-HH V91L GCK mutant in INS-1 832/13 cells to determine the effect of the mutation on β-cell viability and the mechanisms of β-cell death. We showed that expression of the V91L GCK mutant in INS-1 832/13 cells resulted in a rapid glucose concentration-dependent loss of cell viability. At 11 mM D-glucose, INS-1 832/13 cells expressing V91L GCK showed increased cell permeability without significant increases in Annexin V staining or caspase 3/7 activation, indicating that these cells are primarily undergoing cell death via necrosis. Over-expression of SV40 large T antigen, which inhibits the p53 pathway, did not affect the V91L GCK-induced cell death. We also found that non-phosphorylatable L-glucose did not induce rapid cell death. Of note, glucose phosphorylation coincided with a 90% loss of intracellular ATP content. Thus, our data suggest that the GCK V91L mutant induces rapid necrosis in INS-1 cells through accelerated glucose phosphorylation, ATP depletion, and increased cell permeability. V91L glucokinase mutant induces glucose-dependent death in rat INS-1 832/13 cells. Glucose induces necrosis in INS-1 832/13 cells expressing V91L glucokinase mutant. V91L glucokinase mutant depletes adenosine triphosphate in INS-1 832/13 cells.
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Affiliation(s)
- Brian Lu
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA.,Virology and Gene Therapy Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | - Jason M Tonne
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Yasuhiro Ikeda
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA.,Virology and Gene Therapy Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
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First evidence of changes in enzyme kinetics and stability of glucokinase affected by somatic cancer-associated variations. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1867:213-218. [PMID: 30590153 DOI: 10.1016/j.bbapap.2018.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/07/2018] [Accepted: 12/20/2018] [Indexed: 12/27/2022]
Abstract
Recent investigation of somatic variations of allosterically regulated proteins in cancer genomes suggested that variations in glucokinase (GCK) might play a role in tumorigenesis. We hypothesized that somatic cancer-associated GCK variations include in part those with activating and/or stabilizing effects. We analyzed the enzyme kinetics and thermostability of recombinant proteins possessing the likely activating variations and the variations present in the connecting loop I and provided the first experimental evidence of the effects of somatic cancer-associated GCK variations. Activating and/or stabilizing variations were common among the analyzed cancer-associated variations, which was in strong contrast to their low frequency among germinal variations. The activating and stabilizing variations displayed focal distribution with respect to the tertiary structure, and were present in the surroundings of the heterotropic allosteric activator site, including but not limited to the connecting loop I and in the active site region subject to extensive rearrangements upon glucose binding. Activating somatic cancer-associated variations induced a reduction of GCK's cooperativity and an increase in the affinity to glucose (a decline in the S0.5 values). The hotspot-associated variations, which decreased cooperativity, also increased the half-maximal inhibitory concentrations of the competitive GCK inhibitor, N-acetylglucosamine. Concluded, we have provided the first convincing biochemical evidence establishing GCK as a previously unrecognized enzyme that contributes to the reprogramming of energy metabolism in cancer cells. Activating GCK variations substantially increase affinity of GCK to glucose, disrupt the otherwise characteristic sigmoidal response to glucose and/or prolong the enzyme half-life. This, combined, facilitates glucose phosphorylation, thus supporting glycolysis and associated pathways.
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Liu L, Liu Y, Ge X, Liu X, Chen C, Wang Y, Li M, Yin J, Zhang J, Chen Y, Zhang R, Jiang Y, Zhao W, Yang D, Zheng T, Lu M, Zhuang L, Jiang M. Insights into pathogenesis of five novel GCK mutations identified in Chinese MODY patients. Metabolism 2018; 89:8-17. [PMID: 30257192 DOI: 10.1016/j.metabol.2018.09.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/29/2018] [Accepted: 09/19/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Heterozygous inactivating mutations in GCK are associated with defects in pancreatic insulin secretion and/or hepatic glycogen synthesis leading to mild chronic hyperglycaemia of maturity onset diabetes of young type 2 (MODY2). However, the effect of naturally occurring GCK mutations on the pathogenesis for MODY2 hyperglycaemia remains largely unclear, especially in the Asian population. The aim of this study is to explore the potential pathogenicity of novel GCK mutations related to MODY2. METHODS Genetic screening for GCK mutations from 96 classical MODY families was performed, and structure-function characterization and clinical profile of identified GCK mutations were conducted. RESULTS Five novel (F195S, I211T, V222D, E236G and K458R) and five known (T49N, I159V, R186X, A188T and M381T) mutations were identified and co-segregated with hyperglycaemia in their pedigrees. R186X generates non-functional truncated form and V222D and E236G fully inactivate glucokinase due to severe structure disruptions. The other seven GCK mutations exhibited marked reductions in catalytic efficiency and thermo-stability; notably, the interaction with GKRP was significantly enhanced in I211T, I159V, T49N and K458R, reduced in F195S and M381T, and completely lost with A188T. 31% (17/55) of MODY2 patients showed signs of insulin resistance. Conventional hypoglycaemia treatment did not improve the HbA1C in MODY2 patients when insulin resistance is not present. CONCLUSIONS Five novel GCK mutations have been identified in Chinese MODY. The defects in enzymatic activity and protein stability, together with alteration of GKRP binding on GCK mutants may synergistically contribute to the development of MODY2 hyperglycaemia. No treatment should be prescribed to MODY2 patients when insulin resistance is not present.
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Affiliation(s)
- Limei Liu
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China.
| | - Yanjun Liu
- Department of Internal Medicine, Charles R. Drew University, USA; David Geffen School of Medicine at University of California, USA
| | - Xiaoxu Ge
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Xipeng Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dong-Chuan Road, Shanghai 200240, China
| | - Chen Chen
- Department of Molecular Cell and Biology, University of California at Berkeley, USA
| | - Yanzhong Wang
- School of Population Health and Environmental Science, King's College London, UK
| | - Ming Li
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Jun Yin
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Juan Zhang
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Yating Chen
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Rong Zhang
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Yanyan Jiang
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Weijing Zhao
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Di Yang
- Department of Nutritional Sciences and Toxicology, University of California at Berkeley, USA
| | - Taishan Zheng
- Shanghai Diabetes Institute, Department of Endocrinology & Metabolism, Shanghai Key Clinical Center for Metabolic Disease, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, China
| | - Ming Lu
- Department of Endocrinology & Metabolism, Putuo Hospital Attached to Shanghai University of Traditional Chinese Medicine, 164 Lanxi Road, Shanghai 200000, China
| | - Langen Zhuang
- Department of Endocrinology, the First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233004, China
| | - Meisheng Jiang
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Martínez R, Gutierrez-Nogués Á, Fernández-Ramos C, Velayos T, Vela A, Navas MÁ, Castaño L. Heterogeneity in phenotype of hyperinsulinism caused by activating glucokinase mutations: a novel mutation and its functional characterization. Clin Endocrinol (Oxf) 2017; 86:778-783. [PMID: 28247534 DOI: 10.1111/cen.13318] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 12/12/2016] [Accepted: 02/23/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND Mutations in the GCK gene lead to different forms of glucokinase (GCK)-disease, activating mutations cause hyperinsulinaemic hypoglycaemia while inactivating mutations cause monogenic diabetes. Hyperinsulinism (HI) is a heterogeneous condition with a significant genetic component. The major causes are channelopathies, the other forms are rare and being caused by mutations in genes such as GCK. OBJECTIVE To describe the clinical and genetic presentation of four families with activating GCK mutations, and to explore the pathogenicity of the novel mutation identified through functional studies. RESULTS Four cases of HI with mutations in GCK were identified. These include one novel mutation (p.Trp99Cys). Functional analysis of the purified mutant fusion protein glutathione-S-transferase (GST)-GCK-p.Trp99Cys demonstrated that p.Trp99Cys is an activating mutation as it induces a higher affinity for glucose and increases the relative activity index more than 11 times. Moreover, the thermal stability of the mutant protein was similar to that of its wild type. All patients were responsive to diazoxide treatment. One of the mutations arose de novo, and two were dominantly inherited, although only one of them from an HI affected parent. The age of presentation in our cases varied widely from the neonatal period to adulthood. CONCLUSION The clinical phenotype of the GCK activating mutation carriers was heterogeneous, the severity of symptoms and age at presentation varied markedly between affected individuals, even within the same family. The novel activating GCK mutation (p.Trp99Cys) has a strong activating effect in vitro although it has been identified in one case of a milder and late-onset form of HI.
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Affiliation(s)
- Rosa Martínez
- Endocrinology and Diabetes Research Group, BioCruces Health Research Institute, UPV-EHU, CIBERDEM, CIBERER, Cruces University Hospital, Barakaldo, Spain
| | - Ángel Gutierrez-Nogués
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, CIBERDEM and Hospital Clínico San Carlos Health Research Institute, Complutense University of Madrid, Madrid, Spain
| | - Concepción Fernández-Ramos
- Pediatric Endocrinology Section, BioCruces Health Research Institute, UPV/EHU, Basurto University Hospital, Bilbao, Spain
| | - Teresa Velayos
- Endocrinology and Diabetes Research Group, BioCruces Health Research Institute, UPV-EHU, CIBERDEM, CIBERER, Cruces University Hospital, Barakaldo, Spain
| | - Amaia Vela
- Pediatric Endocrinology Section, BioCruces Health Research Institute, UPV/EHU, Cruces University Hospital, CIBERDEM, CIBERER, Barakaldo, Bizkaia, Spain
| | - María-Ángeles Navas
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, CIBERDEM and Hospital Clínico San Carlos Health Research Institute, Complutense University of Madrid, Madrid, Spain
| | - Luis Castaño
- Endocrinology and Diabetes Research Group, BioCruces Health Research Institute, UPV-EHU, CIBERDEM, CIBERER, Cruces University Hospital, Barakaldo, Spain
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14
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Ajala ON, Huffman DM, Ghobrial II. Glucokinase mutation-a rare cause of recurrent hypoglycemia in adults: a case report and literature review. J Community Hosp Intern Med Perspect 2016; 6:32983. [PMID: 27802864 PMCID: PMC5089152 DOI: 10.3402/jchimp.v6.32983] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/30/2016] [Indexed: 02/02/2023] Open
Abstract
Background Hypoglycemia occurs frequently in patients both in the inpatient and outpatient settings. While most hypoglycemia unrelated to diabetes treatment results from excessive endogenous insulin action, rare cases involve functional and congenital mutations in glycolytic enzymes of insulin regulation. Case A 21-year-old obese woman presented to the emergency department with complaints of repeated episodes of lethargy, syncope, dizziness, and sweating. She was referred from an outside facility on suspicion of insulinoma, with severe hypoglycemia unresponsive to repeated dextrose infusions. Her plasma glucose was 20 mg/dl at presentation, 44 mg/dl on arrival at our facility, and remained low in spite of multiple dextrose infusions. The patient had been treated for persistent hyperinsulinemic hypoglycemia of infancy at our neonatal facility and 4 years ago was diagnosed as having an activating glucokinase (GCK) mutation. She was then treated with octreotide and diazoxide with improvement in symptoms and blood glucose levels. Conclusion Improved diagnostication and management of uncommon genetic mutations as typified in this patient with an activating mutation of the GCK gene has expanded the spectrum of disease in adult medicine. This calls for improved patient information dissemination across different levels and aspects of the health care delivery system to ensure cost-effective and timely health care.
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Affiliation(s)
- Oluremi N Ajala
- Department of Internal Medicine, University of Pittsburgh Medical Center, McKeesport, PA, USA;
| | - David M Huffman
- Department of Internal Medicine, University of Tennessee College of Medicine, Chattanooga, TN, USA
| | - Ibrahim I Ghobrial
- Department of Internal Medicine, University of Pittsburgh Medical Center, McKeesport, PA, USA
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15
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Challis BG, Harris J, Sleigh A, Isaac I, Orme SM, Seevaratnam N, Dhatariya K, Simpson HL, Semple RK. Familial adult onset hyperinsulinism due to an activating glucokinase mutation: implications for pharmacological glucokinase activation. Clin Endocrinol (Oxf) 2014; 81:855-61. [PMID: 24890200 PMCID: PMC4735948 DOI: 10.1111/cen.12517] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 05/11/2014] [Accepted: 05/27/2014] [Indexed: 01/13/2023]
Abstract
CONTEXT Glucokinase (GCK) phosphorylates and thereby "traps" glucose in cells, thus serving as a gatekeeper for cellular glucose metabolism, particularly in hepatocytes and pancreatic beta cells. In humans, activating GCK mutations cause familial hyperinsulinaemic hypoglycaemia (GCK-HH), leading to keen interest in the potential of small-molecule glucokinase activators (GKAs) as treatments for diabetes mellitus. Many such agents have been developed; however, observation of side effects including hypertriglyceridaemia and hepatic steatosis has delayed their clinical development. OBJECTIVE To describe the clinical presentation and metabolic profiles of affected family members in a kindred with familial hyperinsulinism of adult presentation due to a known activating mutation in GCK. DESIGN Clinical, biochemical and metabolic assessment, and GCK sequencing in affected family members. RESULTS In the 60-year-old female proband, hyperinsulinaemic hypoglycaemia (blood glucose 2·1 mmol/mol, insulin 18 pm) was confirmed following 34 h of fasting; however, abdominal computed tomography (CT), pancreatic MRI, endoscopic ultrasound, octreotide scintigraphy and selective arterial calcium stimulation failed to localize an insulinoma. A prolonged OGTT revealed fasting hypoglycaemia that was exacerbated after glucose challenge, consistent with dysregulated glucose-stimulated insulin release. A heterozygous activating mutation, p.Val389Leu, in the glucokinase gene (GCK) was found in the proband and four other family members. Of these, two had been investigated elsewhere for recurrent hypoglycaemia in adulthood, while the other two adult relatives were asymptomatic despite profound hypoglycaemia. All three of the available family members with the p.Val389Leu mutation had normal serum lipid profiles, normal rates of fasting hepatic de novo lipogenesis and had hepatic triglyceride levels commensurate with their degree of adiposity. CONCLUSION Activating GCK mutations may present in late adulthood with hyperinsulinaemic hypoglycaemia and should be considered even in older patients being investigated for insulinoma. Normal circulating lipids, rates of hepatic de novo lipogenesis and appropriate hepatic triglyceride content for degree of adiposity in the patients we describe suggest that even lifelong GCK activation in isolation is insufficient to produce fatty liver and metabolic dyslipidaemia.
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Affiliation(s)
- Benjamin G Challis
- University of Cambridge Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
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16
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Costantini S, Malerba G, Contreas G, Corradi M, Marin Vargas S, Giorgetti A, Maffeis C. Genetic and bioinformatics analysis of four novelGCKmissense variants detected in Caucasian families with GCK-MODY phenotype. Clin Genet 2014; 87:440-7. [DOI: 10.1111/cge.12406] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 04/10/2014] [Accepted: 04/14/2014] [Indexed: 01/19/2023]
Affiliation(s)
- S. Costantini
- Regional Center for Pediatric Diabetes; Clinical Nutrition and Obesity, Department of Life and Reproduction Sciences
| | - G. Malerba
- Section of Biology and Genetics; Department of Life and Reproduction Sciences
| | - G. Contreas
- Regional Center for Pediatric Diabetes; Clinical Nutrition and Obesity, Department of Life and Reproduction Sciences
| | - M. Corradi
- Regional Center for Pediatric Diabetes; Clinical Nutrition and Obesity, Department of Life and Reproduction Sciences
| | - S.P. Marin Vargas
- Applied Bioinformatics Lab., Department of Biotechnology; University of Verona; Verona Italy
| | - A. Giorgetti
- Applied Bioinformatics Lab., Department of Biotechnology; University of Verona; Verona Italy
| | - C. Maffeis
- Regional Center for Pediatric Diabetes; Clinical Nutrition and Obesity, Department of Life and Reproduction Sciences
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17
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Kavvoura FK, Raimondo A, Thanabalasingham G, Barrett A, Webster AL, Shears D, Mann NP, Ellard S, Gloyn AL, Owen KR. Reclassification of diabetes etiology in a family with multiple diabetes phenotypes. J Clin Endocrinol Metab 2014; 99:E1067-71. [PMID: 24606082 PMCID: PMC4186945 DOI: 10.1210/jc.2013-3641] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Maturity-onset diabetes of the young (MODY) is uncommon; however, accurate diagnosis facilitates personalized management and informs prognosis in probands and relatives. OBJECTIVE The objective of the study was to highlight that the appropriate use of genetic and nongenetic investigations leads to the correct classification of diabetes etiology. CASE DISCUSSION A 30-year-old European female was diagnosed with insulin-treated gestational diabetes. She discontinued insulin after delivery; however, her fasting hyperglycemia persisted. β-Cell antibodies were negative and C-peptide was 0.79 nmol/L. Glucokinase (GCK)-MODY was suspected and confirmed by the identification of a GCK mutation (p.T206M). METHODS Systematic clinical and biochemical characterization and GCK mutational analysis were implemented to determine the diabetes etiology in five relatives. Functional characterization of GCK mutations was performed. RESULTS Identification of the p.T206M mutation in the proband's sister confirmed a diagnosis of GCK-MODY. Her daughter was diagnosed at 16 weeks with permanent neonatal diabetes (PNDM). Mutation analysis identified two GCK mutations that were inherited in trans-p. [(R43P);(T206M)], confirming a diagnosis of GCK-PNDM. Both mutations were shown to be kinetically inactivating. The proband's mother, other sister, and daughter all had a clinical diagnosis of type 1 diabetes, confirmed by undetectable C-peptide levels and β-cell antibody positivity. GCK mutations were not detected. CONCLUSIONS Two previously misclassified family members were shown to have GCK-MODY, whereas another was shown to have GCK-PNDM. A diagnosis of type 1 diabetes was confirmed in three relatives. This family exemplifies the importance of careful phenotyping and systematic evaluation of relatives after discovering monogenic diabetes in an individual.
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Affiliation(s)
- Fotini K Kavvoura
- Oxford Centre for Diabetes, Endocrinology, and Metabolism (F.K.K., A.R., G.T., A.B., A.L.W., A.L.G., K.R.O.), University of Oxford, Oxford OX3 7LE, United Kingdom; Oxford National Institute for Health Research Biomedical Centre (F.K.K., G.T., A.L.G., K.R.O.), Churchill Hospital, Oxford OX3 7LJ, United Kingdom; Department of Clinical Genetics (D.S.), Oxford University Hospitals National Health Service Trust, Oxford OX3 9DU, United Kingdom; Department of Pediatrics (N.P.M.), Royal Berkshire National Health Service Foundation Trust, Reading RG1 5AN, United Kingdom; and Institute of Biomedical and Clinical Science (S.E.), University of Exeter Medical School, Exeter EX4 4PY, United Kingdom
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18
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Barros CC, Haro A, Russo FJ, Schadock I, Almeida SS, Reis FC, Moraes MR, Haidar A, Hirata AE, Mori M, Bacurau RFP, Würtele M, Bader M, Pesquero JB, Araujo RC. Bradykinin inhibits hepatic gluconeogenesis in obese mice. J Transl Med 2012; 92:1419-27. [PMID: 22868909 DOI: 10.1038/labinvest.2012.105] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The kallikrein-kinin system (KKS) has been previously linked to glucose homeostasis. In isolated muscle or fat cells, acute bradykinin (BK) stimulation was shown to improve insulin action and increase glucose uptake by promoting glucose transporter 4 translocation to plasma membrane. However, the role for BK in the pathophysiology of obesity and type 2 diabetes remains largely unknown. To address this, we generated genetically obese mice (ob/ob) lacking the BK B2 receptor (obB2KO). Despite similar body weight or fat accumulation, obB2KO mice showed increased fasting glycemia (162.3 ± 28.2 mg/dl vs 85.3 ± 13.3 mg/dl), hyperinsulinemia (7.71 ± 1.75 ng/ml vs 4.09 ± 0.51 ng/ml) and impaired glucose tolerance when compared with ob/ob control mice (obWT), indicating insulin resistance and impaired glucose homeostasis. This was corroborated by increased glucose production in response to a pyruvate challenge. Increased gluconeogenesis was accompanied by increased hepatic mRNA expression of forkhead box protein O1 (FoxO1, four-fold), peroxisome proliferator-activated receptor gamma co-activator 1-alpha (seven-fold), phosphoenolpyruvate carboxykinase (PEPCK, three-fold) and glucose-6-phosphatase (eight-fold). FoxO1 nuclear exclusion was also impaired, as the obB2KO mice showed increased levels of this transcription factor in the nucleus fraction of liver homogenates during random feeding. Intraportal injection of BK in lean mice was able to decrease the hepatic mRNA expression of FoxO1 and PEPCK. In conclusion, BK modulates glucose homeostasis by affecting hepatic glucose production in obWT. These results point to a protective role of the KKS in the pathophysiology of type 2 diabetes mellitus.
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Beer NL, Osbak KK, van de Bunt M, Tribble ND, Steele AM, Wensley KJ, Edghill EL, Colcough K, Barrett A, Valentínová L, Rundle JK, Raimondo A, Grimsby J, Ellard S, Gloyn AL. Insights into the pathogenicity of rare missense GCK variants from the identification and functional characterization of compound heterozygous and double mutations inherited in cis. Diabetes Care 2012; 35:1482-4. [PMID: 22611063 PMCID: PMC3379612 DOI: 10.2337/dc11-2420] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 03/09/2012] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To demonstrate the importance of using a combined genetic and functional approach to correctly interpret a genetic test for monogenic diabetes. RESEARCH DESIGN AND METHODS We identified three probands with a phenotype consistent with maturity-onset diabetes of the young (MODY) subtype GCK-MODY, in whom two potential pathogenic mutations were identified: [R43H/G68D], [E248 K/I225M], or [G261R/D217N]. Allele-specific PCR and cosegregation were used to determine phase. Single and double mutations were kinetically characterized. RESULTS The mutations occurred in cis (double mutants) in two probands and in trans in one proband. Functional studies of all double mutants revealed inactivating kinetics. The previously reported GCK-MODY mutations R43H and G68D were inherited from an affected father and unaffected mother, respectively. Both our functional and genetic studies support R43H as the cause of GCK-MODY and G68D as a neutral rare variant. CONCLUSIONS These data highlight the need for family/functional studies, even for previously reported pathogenic mutations.
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Affiliation(s)
- Nicola L. Beer
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts
| | - Kara K. Osbak
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Martijn van de Bunt
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Nicholas D. Tribble
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Anna M. Steele
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Kirsty J. Wensley
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Emma L. Edghill
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
| | - Kevin Colcough
- Molecular Genetics Department, Royal Devon and Exeter NHS Trust, Exeter, U.K
| | - Amy Barrett
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Lucia Valentínová
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
- Institute of Experimental Endocrinology, Slovak Academy of Science, Bratislava, Slovakia
| | - Jana K. Rundle
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Anne Raimondo
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
| | - Joseph Grimsby
- Department of Metabolic Diseases, Hoffmann-La Roche Inc., Nutley, New Jersey
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Exeter, U.K
- Molecular Genetics Department, Royal Devon and Exeter NHS Trust, Exeter, U.K
| | - Anna L. Gloyn
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Oxford, U.K
- Oxford National Institute for Health Research, Churchill Hospital, Oxford, U.K
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Identification and functional characterisation of novel glucokinase mutations causing maturity-onset diabetes of the young in Slovakia. PLoS One 2012; 7:e34541. [PMID: 22493702 PMCID: PMC3321013 DOI: 10.1371/journal.pone.0034541] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/01/2012] [Indexed: 11/19/2022] Open
Abstract
Heterozygous glucokinase (GCK) mutations cause a subtype of maturity-onset diabetes of the young (GCK-MODY). Over 600 GCK mutations have been reported of which ∼65% are missense. In many cases co-segregation has not been established and despite the importance of functional studies in ascribing pathogenicity for missense variants these have only been performed for <10% of mutations. The aim of this study was to determine the minimum prevalence of GCK-MODY amongst diabetic subjects in Slovakia by sequencing GCK in 100 Slovakian probands with a phenotype consistent with GCK-MODY and to explore the pathogenicity of identified variants through family and functional studies. Twenty-two mutations were identified in 36 families (17 missense) of which 7 (I110N, V200A, N204D, G258R, F419S, c.580-2A>C, c.1113-1114delGC) were novel. Parental DNA was available for 22 probands (covering 14/22 mutations) and co-segregation established in all cases. Bioinformatic analysis predicted all missense mutations to be damaging. Nine (I110N, V200A, N204D, G223S, G258R, F419S, V244G, L315H, I436N) mutations were functionally evaluated. Basic kinetic analysis explained pathogenicity for 7 mutants which showed reduced glucokinase activity with relative activity indices (RAI) between 0.6 to <0.001 compared to wild-type GCK (1.0). For the remaining 2 mutants additional molecular mechanisms were investigated. Differences in glucokinase regulatory protein (GKRP) -mediated-inhibition of GCK were observed for both L315H & I436N when compared to wild type (IC(50) 14.6±0.1 mM & 20.3±1.6 mM vs.13.3±0.1 mM respectively [p<0.03]). Protein instability as assessed by thermal lability studies demonstrated that both L315H and I436N show marked thermal instability compared to wild-type GCK (RAI at 55°C 8.8±0.8% & 3.1±0.4% vs. 42.5±3.9% respectively [p<0.001]). The minimum prevalence of GCK-MODY amongst Slovakian patients with diabetes was 0.03%. In conclusion, we have identified 22 GCK mutations in 36 Slovakian probands and demonstrate that combining family, bioinformatic and functional studies can aid the interpretation of variants identified by molecular diagnostic screening.
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