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Costa-Riquetto AD, de Santana LS, Franco PC, Jr ACS, Martio AE, Lisboa HRK, Kohara SK, Teles MG. Genetic and clinical features of neonatal and early onset diabetes mellitus in a tertiary center cohort in Brazil. Clin Genet 2023; 103:434-447. [PMID: 36510364 DOI: 10.1111/cge.14279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022]
Abstract
Neonatal diabetes mellitus (NDM) is defined as the occurrence of severe hyperglycemia in infants under 6 months old and may be permanent (PNDM) or transient (TNDM). When diabetes is diagnosed at 6-12 months of age (early onset diabetes [EOD]), the etiology may be monogenic; however, most cases consist of type 1 diabetes mellitus (T1DM). Molecular diagnosis was determined in a cohort of 35 unrelated Brazilian patients with NDM or EOD based on targeted next-generation sequencing panel and/or chromosome 6q24 abnormalities. The impact of genetic testing on treatment and follow-up was evaluated. Overall, 24 patients had NDM: with 18 (75.0%) having PNDM, 5 TNDM (20.8%) and 1 case in which this information was unknown. Eleven patients had EOD. Genetic testing was positive in 20/24 patients with NDM (83.3%) and in 18.2% of cases of EOD. The commonest causes were ATP-sensitive potassium (KATP) channel genes, and GCK and IPEX mutations (37.1%, 11.4% and 5.7%, respectively). Patients with PNDM due to KCNJ11 and ABCC8 mutations transitioned successfully to sulfonylureas in almost 60% of cases, reinforcing the benefit of performing genetic testing in NDM as early as possible. This report refers to the largest series of cases of NDM (TNDM and PNDM) and EOD in Brazil in which patients were submitted to molecular investigation and in which the clinical impact of genetic diagnosis was also evaluated.
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Affiliation(s)
- Aline Dantas Costa-Riquetto
- Grupo de Diabetes Monogênico (Monogenic Diabetes Group), Unidade de Endocrinologia Genética (LIM25), Unidade de Diabetes, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (HCFMUSP), São Paulo, Brazil
| | - Lucas Santos de Santana
- Grupo de Diabetes Monogênico (Monogenic Diabetes Group), Unidade de Endocrinologia Genética (LIM25), Unidade de Diabetes, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (HCFMUSP), São Paulo, Brazil
| | - Pedro Campos Franco
- Grupo de Diabetes Monogênico (Monogenic Diabetes Group), Unidade de Endocrinologia Genética (LIM25), Unidade de Diabetes, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (HCFMUSP), São Paulo, Brazil
| | - Augusto Cezar Santomauro Jr
- Grupo de Diabetes Monogênico (Monogenic Diabetes Group), Unidade de Endocrinologia Genética (LIM25), Unidade de Diabetes, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (HCFMUSP), São Paulo, Brazil
| | | | | | | | - Milena G Teles
- Grupo de Diabetes Monogênico (Monogenic Diabetes Group), Unidade de Endocrinologia Genética (LIM25), Unidade de Diabetes, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (HCFMUSP), São Paulo, Brazil
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2
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Role of Actionable Genes in Pursuing a True Approach of Precision Medicine in Monogenic Diabetes. Genes (Basel) 2022; 13:genes13010117. [PMID: 35052457 PMCID: PMC8774614 DOI: 10.3390/genes13010117] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 12/16/2022] Open
Abstract
Monogenic diabetes is a genetic disorder caused by one or more variations in a single gene. It encompasses a broad spectrum of heterogeneous conditions, including neonatal diabetes, maturity onset diabetes of the young (MODY) and syndromic diabetes, affecting 1-5% of patients with diabetes. Some of these variants are harbored by genes whose altered function can be tackled by specific actions ("actionable genes"). In suspected patients, molecular diagnosis allows the implementation of effective approaches of precision medicine so as to allow individual interventions aimed to prevent, mitigate or delay clinical outcomes. This review will almost exclusively concentrate on the clinical strategy that can be specifically pursued in carriers of mutations in "actionable genes", including ABCC8, KCNJ11, GCK, HNF1A, HNF4A, HNF1B, PPARG, GATA4 and GATA6. For each of them we will provide a short background on what is known about gene function and dysfunction. Then, we will discuss how the identification of their mutations in individuals with this form of diabetes, can be used in daily clinical practice to implement specific monitoring and treatments. We hope this article will help clinical diabetologists carefully consider who of their patients deserves timely genetic testing for monogenic diabetes.
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3
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Abstract
Although type 1 diabetes mellitus and, to a lesser extent, type 2 diabetes mellitus, are the prevailing forms of diabetes in youth, atypical forms of diabetes are not uncommon and may require etiology-specific therapies. By some estimates, up to 6.5% of children with diabetes have monogenic forms. Mitochondrial diabetes and cystic fibrosis related diabetes are less common but often noted in the underlying disease. Atypical diabetes should be considered in patients with a known disorder associated with diabetes, aged less than 25 years with nonautoimmune diabetes and without typical characteristics of type 2 diabetes mellitus, and/or with comorbidities associated with atypical diabetes.
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Affiliation(s)
- Jaclyn Tamaroff
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3500 Civic Center Boulevard, 12th Floor, Philadelphia, PA 19104, USA.
| | - Marissa Kilberg
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3500 Civic Center Boulevard, 12th Floor, Philadelphia, PA 19104, USA
| | - Sara E Pinney
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3500 Civic Center Boulevard, 12th Floor, Philadelphia, PA 19104, USA
| | - Shana McCormack
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, 3500 Civic Center Boulevard, 12th Floor, Philadelphia, PA 19104, USA
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4
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Abstract
Diabetes mellitus is a chronic heterogeneous metabolic disorder with complex pathogenesis. It is characterized by elevated blood glucose levels or hyperglycemia, which results from abnormalities in either insulin secretion or insulin action or both. Hyperglycemia manifests in various forms with a varied presentation and results in carbohydrate, fat, and protein metabolic dysfunctions. Long-term hyperglycemia often leads to various microvascular and macrovascular diabetic complications, which are mainly responsible for diabetes-associated morbidity and mortality. Hyperglycemia serves as the primary biomarker for the diagnosis of diabetes as well. In this review, we would be focusing on the classification of diabetes and its pathophysiology including that of its various types.
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Affiliation(s)
- Mujeeb Z Banday
- Department of Biochemistry, Government Medical College and Associated Shri Maharaja Hari Singh Hospital, Srinagar, Kashmir, India
| | - Aga S Sameer
- Department of Basic Medical Sciences, College of Medicine, King Saud Bin Abdul Aziz University for Health Sciences, King Abdullah International Medical Research Centre, National Guard Health Affairs, Jeddah, Saudi Arabia
| | - Saniya Nissar
- Department of Biochemistry, Government Medical College and Associated Shri Maharaja Hari Singh Hospital, Srinagar, Kashmir, India
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5
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De Franco E, Saint-Martin C, Brusgaard K, Knight Johnson AE, Aguilar-Bryan L, Bowman P, Arnoux JB, Larsen AR, Sanyoura M, Greeley SAW, Calzada-León R, Harman B, Houghton JAL, Nishimura-Meguro E, Laver TW, Ellard S, Del Gaudio D, Christesen HT, Bellanné-Chantelot C, Flanagan SE. Update of variants identified in the pancreatic β-cell K ATP channel genes KCNJ11 and ABCC8 in individuals with congenital hyperinsulinism and diabetes. Hum Mutat 2020; 41:884-905. [PMID: 32027066 PMCID: PMC7187370 DOI: 10.1002/humu.23995] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 01/08/2020] [Accepted: 02/04/2020] [Indexed: 01/03/2023]
Abstract
The most common genetic cause of neonatal diabetes and hyperinsulinism is pathogenic variants in ABCC8 and KCNJ11. These genes encode the subunits of the β-cell ATP-sensitive potassium channel, a key component of the glucose-stimulated insulin secretion pathway. Mutations in the two genes cause dysregulated insulin secretion; inactivating mutations cause an oversecretion of insulin, leading to congenital hyperinsulinism, whereas activating mutations cause the opposing phenotype, diabetes. This review focuses on variants identified in ABCC8 and KCNJ11, the phenotypic spectrum and the treatment implications for individuals with pathogenic variants.
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Affiliation(s)
- Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Cécile Saint-Martin
- Department of Genetics, Pitié-Salpêtrière Hospital, AP-HP, Sorbonne University, Paris, France
| | - Klaus Brusgaard
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Amy E Knight Johnson
- Department of Human Genetics, University of Chicago Genetic Services Laboratory, The University of Chicago, Chicago, Illinois
| | | | - Pamela Bowman
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Jean-Baptiste Arnoux
- Reference Center for Inherited Metabolic Diseases, Necker-Enfants Malades Hospital, Paris, France
| | - Annette Rønholt Larsen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark
| | - May Sanyoura
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, Kovler Diabetes Center, University of Chicago, Chicago, Illinois
| | - Siri Atma W Greeley
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, Kovler Diabetes Center, University of Chicago, Chicago, Illinois
| | - Raúl Calzada-León
- Pediatric Endocrinology, Endocrine Service, National Institute for Pediatrics, Mexico City, Mexico
| | - Bradley Harman
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Jayne A L Houghton
- Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Elisa Nishimura-Meguro
- Department of Pediatric Endocrinology, Children's Hospital, National Medical Center XXI Century, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Thomas W Laver
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.,Department of Molecular Genetics, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Daniela Del Gaudio
- Department of Human Genetics, University of Chicago Genetic Services Laboratory, The University of Chicago, Chicago, Illinois
| | - Henrik Thybo Christesen
- Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark.,Odense Pancreas Center, Odense University Hospital, Odense, Denmark
| | | | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK
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Ang SF, Tan CSH, Fong JCW, Lim SC. Precision medicine for a man presented with diabetes at 2-month old. Eur J Hum Genet 2019; 27:989-993. [PMID: 30890782 DOI: 10.1038/s41431-019-0371-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 01/31/2019] [Accepted: 02/16/2019] [Indexed: 10/27/2022] Open
Abstract
A 22-year-old man was referred for continuation of diabetes mellitus treatment. He was first diagnosed with diabetes mellitus 2 months after birth, when he failed to thrive and showed symptoms of diabetic ketoacidosis. There was no family history of diabetes mellitus. The patient did not exhibit the full set of features to be qualified for any developmental delay, epilepsy and neonatal diabetes mellitus (DEND) syndrome. Insulin replacement therapy was initiated; however, management was challenged by wide glycemic excursion, hypoglycemic unawareness and insulin-associated cutaneous lipo-hypertrophy. Re-evaluation, including genetic testing, revealed a heterozygous missense p.Arg201Cys variation in the KCNJ11 gene encoding the potassium channel subunit Kir6.2. Successful treatment conversion from insulin to glibenclamide was achieved over an extended period of 2 months (up-titrating to a dose of 1.0 mg/kg) in this patient despite his long diabetes duration of 27 years with elimination of hypoglycemia unawareness and achievement of excellent glycemic control sustained over more than 5 years. This case highlights the importance of after having secured a firm genetic diagnosis, to undertake conversion to sulphonylurea with careful dose titration and perseverance over months. Confirmation of variants with functional implications by genetic testing in patients suspected of neonatal diabetes is important for accurate molecular diagnosis and precision-treatment strategy with optimal outcome.
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Affiliation(s)
- Su Fen Ang
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore, Singapore
| | - Clara Si Hua Tan
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore, Singapore
| | | | - Su Chi Lim
- Clinical Research Unit, Khoo Teck Puat Hospital (KTPH), Singapore, Singapore. .,Diabetes Centre, , Khoo Teck Puat Hospital (KTPH), Singapore, Singapore. .,Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore.
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Onaolapo AY, Onaolapo OJ. Circadian dysrhythmia-linked diabetes mellitus: Examining melatonin’s roles in prophylaxis and management. World J Diabetes 2018; 9:99-114. [PMID: 30079146 PMCID: PMC6068738 DOI: 10.4239/wjd.v9.i7.99] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 06/01/2018] [Accepted: 06/08/2018] [Indexed: 02/05/2023] Open
Abstract
Diabetes mellitus is a chronic, life-threatening metabolic disorder that occurs worldwide. Despite an increase in the knowledge of the risk factors that are associated with diabetes mellitus, its worldwide prevalence has continued to rise; thus, necessitating more research into its aetiology. Recent researches are beginning to link a dysregulation of the circadian rhythm to impairment of intermediary metabolism; with evidences that circadian rhythm dysfunction might play an important role in the aetiology, course or prognosis of some cases of diabetes mellitus. These evidences thereby suggest possible relationships between the circadian rhythm regulator melatonin, and diabetes mellitus. In this review, we discuss the roles of the circadian rhythm in the regulation of the metabolism of carbohydrates and other macronutrients; with emphasis on the importance of melatonin and the impacts of its deficiency on carbohydrate homeostasis. Also, the possibility of using melatonin and its analogs for the “prophylaxis” or management of diabetes mellitus is also considered.
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Affiliation(s)
- Adejoke Y Onaolapo
- Behavioural Neuroscience/Neurobiology Unit, Department of Anatomy, Ladoke Akintola University of Technology, Ogbomosho 210211, Oyo State, Nigeria
| | - Olakunle J Onaolapo
- Behavioural Neuroscience/Neuropharmacology Unit, Department of Pharmacology, Ladoke Akintola University of Technology, Osogbo 230263, Osun State, Nigeria
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Neonatal Diabetes Mellitus. MEDICAL BULLETIN OF SISLI ETFAL HOSPITAL 2018; 52:71-78. [PMID: 32595377 PMCID: PMC7315067 DOI: 10.14744/semb.2017.51422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 06/07/2017] [Indexed: 11/23/2022]
Abstract
Neonatal diabetes is a rare cause of hyperglycemia in the neonatal period. It is caused by mutations in genes that encode proteins playing critical roles in normal functions of pancreatic beta cells. Neonatal diabetes is divided into temporary and permanent subtypes. Treatment is based on the correction of fluid-electrolyte disturbances and hyperglycemia. Patients respond to insulin or sulfonylurea treatment according to the mutation type. Close glucose monitoring and education of caregivers about diabetes are vital.
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9
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Churbanov A, Abrahamyan L. Preventing Common Hereditary Disorders through Time-Separated Twinning. BIONANOSCIENCE 2018. [DOI: 10.1007/s12668-017-0488-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Dahl AR, Dhamija R, Nofal AA, Pittock ST, Schwenk WF, Kumar S. Transient Neonatal Diabetes due to a Mutation in KCNJ11 in a Child with Klinefelter Syndrome. J Clin Res Pediatr Endocrinol 2018; 10:79-82. [PMID: 28766502 PMCID: PMC5838377 DOI: 10.4274/jcrpe.4807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Klinefelter syndrome is the most frequent chromosomal aneuploidy in males occurring in about 1 in 660 males. Epidemiological studies have demonstrated increased risk of type 1 diabetes and type 2 diabetes in adults with Klinefelter syndrome. There is only one previous report of neonatal diabetes in a patient with Klinefelter syndrome. We report transient neonatal diabetes due to a pathogenic heterozygous variant in KCNJ11 in a male infant with Klinefelter syndrome. A 78-day old male infant was noted to have sustained hyperglycemia with serum glucose ranging between 148 mg/dL (8.2 mmol/L) and 381 mg/dL (21.2 mmol/L) three days after undergoing a complete repair of an atrioventricular defect. Hemoglobin A1c was 6.6%. The patient was born at term with a birth weight of 2.16 kg following a pregnancy complicated by gestational diabetes that was controlled with diet. The patient was initially started on a continuous intravenous insulin drip and subsequently placed on subcutaneous insulin (glargine, human isophane and regular insulin). Insulin was gradually decreased and eventually discontinued at seven months of age. Chromosomal microarray at 11 weeks of age showed XXY and a panel-based, molecular test for neonatal diabetes revealed a pathogenic heterozygous variant c.685G>A (p.Glu229Lys) in KCNJ11. The patient is now 34 months old and continues to have normal fasting and post-prandial glucose and HbA1C levels. The patient will need prospective follow up for assessment of his glycemic status. To our knowledge this is the second reported case of neonatal diabetes in an infant with Klinefelter syndrome and the first due to a mutation in the KCNJ11 in a patient with Klinefelter syndrome.
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Affiliation(s)
- Amanda R. Dahl
- Mayo Clinic, Department of Pediatric and Adolescent Medicine, Rochester, Minnesota, USA
| | - Radhika Dhamija
- Mayo Clinic, Department of Clinical Genomics, Phoenix, Arizona, USA
| | - Alaa Al Nofal
- University of South Dakota, Sanford Children Specialty Clinic, Division of Pediatric Endocrinology, Sioux Falls, South Dakota, USA
| | - Siobhan T. Pittock
- Mayo Clinic, Department of Pediatric and Adolescent Medicine, Division of Pediatric Endocrinology, Rochester, Minnesota, USA
| | - W. Frederick Schwenk
- Mayo Clinic, Department of Pediatric and Adolescent Medicine, Division of Pediatric Endocrinology, Rochester, Minnesota, USA
| | - Seema Kumar
- Mayo Clinic, Department of Pediatric and Adolescent Medicine, Division of Pediatric Endocrinology, Rochester, Minnesota, USA,* Address for Correspondence: Department of Pediatric and Adolescent Medicine, Division of Pediatric Endocrinology, Rochester, Minnesota, USA GSM: +507-284-3300 E-mail:
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11
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Firdous P, Nissar K, Ali S, Ganai BA, Shabir U, Hassan T, Masoodi SR. Genetic Testing of Maturity-Onset Diabetes of the Young Current Status and Future Perspectives. Front Endocrinol (Lausanne) 2018; 9:253. [PMID: 29867778 PMCID: PMC5966560 DOI: 10.3389/fendo.2018.00253] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 05/02/2018] [Indexed: 12/12/2022] Open
Abstract
Diabetes is a global epidemic problem growing exponentially in Asian countries posing a serious threat. Among diabetes, maturity-onset diabetes of the young (MODY) is a heterogeneous group of monogenic disorders that occurs due to β cell dysfunction. Genetic defects in the pancreatic β-cells result in the decrease of insulin production required for glucose utilization thereby lead to early-onset diabetes (often <25 years). It is generally considered as non-insulin dependent form of diabetes and comprises of 1-5% of total diabetes. Till date, 14 genes have been identified and mutation in them may lead to MODY. Different genetic testing methodologies like linkage analysis, restriction fragment length polymorphism, and DNA sequencing are used for the accurate and correct investigation of gene mutations associated with MODY. The next-generation sequencing has emerged as one of the most promising and effective tools to identify novel mutated genes related to MODY. Diagnosis of MODY is mainly relying on the sequential screening of the three marker genes like hepatocyte nuclear factor 1 alpha (HNF1α), hepatocyte nuclear factor 4 alpha (HNF4α), and glucokinase (GCK). Interestingly, MODY patients can be managed by diet alone for many years and may also require minimal doses of sulfonylureas. The primary objective of this article is to provide a review on current status of MODY, its prevalence, genetic testing/diagnosis, possible treatment, and future perspective.
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Affiliation(s)
- Parveena Firdous
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Kamran Nissar
- Department of Biochemistry, University of Kashmir, Srinagar, India
| | - Sajad Ali
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Bashir Ahmad Ganai
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
- *Correspondence: Bashir Ahmad Ganai,
| | - Uzma Shabir
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Toyeeba Hassan
- Centre of Research for Development (CORD), University of Kashmir, Srinagar, India
| | - Shariq Rashid Masoodi
- Department of Endocrinology, Sher-I-Kashmir Institute of Medical Sciences, Srinagar, India
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12
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Remedi MS, Thomas M, Nichols CG, Marshall BA. Sulfonylurea challenge test in subjects diagnosed with type 1 diabetes mellitus. Pediatr Diabetes 2017; 18:777-784. [PMID: 28111849 PMCID: PMC5522783 DOI: 10.1111/pedi.12489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/14/2016] [Accepted: 11/22/2016] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Patients with early onset diabetes because of defects in glucose-stimulated insulin secretion (GSIS) may respond better to sulfonylureas than insulin treatment. Such patients include those with monogenic disorders, who can be differentiated from autoimmune type 1 diabetes mellitus (T1DM) by genetic testing. Genetic testing is expensive and unknown defects in GSIS would not be diagnosed. AIMS We propose a sulfonylurea challenge test to identify patients who have been clinically diagnosed with T1DM, but those who maintain a preferentially sulfonylurea-responsive insulin secretion. MATERIALS & METHODS A total of 3 healthy controls, 2 neonatal diabetes mellitus (NDM) subjects, 3 antibody-positive (Ab+T1DM), and 12 antibody-negative (Ab-T1DM) subjects with type 1 diabetes, were given an intravenous bolus of glucose followed by an oral dose of glipizide. RESULTS Healthy controls showed a robust C-peptide increase after both glucose and glipizide, but NDM subjects showed a large increase in C-peptide only following glipizide. As expected, 2 of 3 Ab+T1DM, as well as 11 of 12 Ab-T1DM showed no response to either glucose or glipizide. However, 1 Ab-T1DM and 1 Ab+T1DM showed a small C-peptide response to glucose and a marked positive response to glipizide, suggesting defects in GSIS rather than typical autoimmune diabetes. DISCUSSION These data demonstrate the feasibility of the sulfonylurea challenge test, and suggest that responder individuals may be identified. CONCLUSIONS We propose that this sulfonylurea challenge test should be explored more extensively, as it may prove useful as a clinical and scientific tool.
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Affiliation(s)
- Maria S. Remedi
- Department of Medicine, Washington University Medical School, St. Louis, MO,Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, MO,Department of Center for the Investigation of Membrane Excitability Diseases, Washington University Medical School, St. Louis, MO
| | - Mareen Thomas
- Department of Pediatrics, Washington University Medical School, St. Louis, MO
| | - Colin G. Nichols
- Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, MO,Department of Center for the Investigation of Membrane Excitability Diseases, Washington University Medical School, St. Louis, MO
| | - Bess A. Marshall
- Department of Pediatrics, Washington University Medical School, St. Louis, MO,Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, MO,Department of Center for the Investigation of Membrane Excitability Diseases, Washington University Medical School, St. Louis, MO,Correspondence should be addressed to: Bess A. Marshall. One Children’s Place, Box 8116, St. Louis, MO, 63110. Phone: (314) 454-6051, Fax: (314) 454-6225.
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13
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Remedi MS, Friedman JB, Nichols CG. Diabetes induced by gain-of-function mutations in the Kir6.1 subunit of the KATP channel. J Gen Physiol 2016; 149:75-84. [PMID: 27956473 PMCID: PMC5217086 DOI: 10.1085/jgp.201611653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022] Open
Abstract
Kir6.2-containing KATP channels are prominent in pancreatic β cells, and gain-of-function mutations in these channels are the most common cause of human neonatal diabetes mellitus. Remedi et al. find that Kir6.1 subunits are also present in pancreatic KATP channels and that gain-of-function mutations can also cause impaired glucose tolerance and insulin secretion. Gain-of-function (GOF) mutations in the pore-forming (Kir6.2) and regulatory (SUR1) subunits of KATP channels have been identified as the most common cause of human neonatal diabetes mellitus. The critical effect of these mutations is confirmed in mice expressing Kir6.2-GOF mutations in pancreatic β cells. A second KATP channel pore-forming subunit, Kir6.1, was originally cloned from the pancreas. Although the prominence of this subunit in the vascular system is well documented, a potential role in pancreatic β cells has not been considered. Here, we show that mice expressing Kir6.1-GOF mutations (Kir6.1[G343D] or Kir6.1[G343D,Q53R]) in pancreatic β cells (under rat-insulin-promoter [Rip] control) develop glucose intolerance and diabetes caused by reduced insulin secretion. We also generated transgenic mice in which a bacterial artificial chromosome (BAC) containing Kir6.1[G343D] is incorporated such that the transgene is only expressed in tissues where Kir6.1 is normally present. Strikingly, BAC-Kir6.1[G343D] mice also show impaired glucose tolerance, as well as reduced glucose- and sulfonylurea-dependent insulin secretion. However, the response to K+ depolarization is intact in Kir6.1-GOF mice compared with control islets. The presence of native Kir6.1 transcripts was demonstrated in both human and wild-type mouse islets using quantitative real-time PCR. Together, these results implicate the incorporation of native Kir6.1 subunits into pancreatic KATP channels and a contributory role for these subunits in the control of insulin secretion.
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Affiliation(s)
- Maria S Remedi
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110 .,Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110.,Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110
| | - Jonathan B Friedman
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110.,Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110
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14
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Modeling K,ATP--dependent excitability in pancreatic islets. Biophys J 2015; 107:2016-26. [PMID: 25418087 DOI: 10.1016/j.bpj.2014.09.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 09/22/2014] [Accepted: 09/30/2014] [Indexed: 11/23/2022] Open
Abstract
In pancreatic ?-cells, K,ATP channels respond to changes in glucose to regulate cell excitability and insulin release. Confirming a high sensitivity of electrical activity to K,ATP activity, mutations that cause gain of K,ATP function cause neonatal diabetes. Our aim was to quantitatively assess the contribution of K,ATP current to the regulation of glucose-dependent bursting by reproducing experimentally observed changes in excitability when K,ATP conductance is altered by genetic manipulation. A recent detailed computational model of single cell pancreatic ?-cell excitability reproduces the ?-cell response to varying glucose concentrations. However, initial simulations showed that the model underrepresents the significance of K,ATP activity and was unable to reproduce K,ATP conductance-dependent changes in excitability. By altering the ATP and glucose dependence of the L-type Ca(2+) channel and the Na-K ATPase to better fit experiment, appropriate dependence of excitability on K,ATP conductance was reproduced. Because experiments were conducted in islets, which contain cell-to-cell variability, we extended the model from a single cell to a three-dimensional model (10×10×10 cell) islet with 1000 cells. For each cell, the conductance of the major currents was allowed to vary as was the gap junction conductance between cells. This showed that single cell glucose-dependent behavior was then highly variable, but was uniform in coupled islets. The study highlights the importance of parameterization of detailed models of ?-cell excitability and suggests future experiments that will lead to improved characterization of ?-cell excitability and the control of insulin secretion.
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Prasad RB, Groop L. Genetics of type 2 diabetes-pitfalls and possibilities. Genes (Basel) 2015; 6:87-123. [PMID: 25774817 PMCID: PMC4377835 DOI: 10.3390/genes6010087] [Citation(s) in RCA: 275] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/28/2015] [Accepted: 02/27/2015] [Indexed: 12/11/2022] Open
Abstract
Type 2 diabetes (T2D) is a complex disease that is caused by a complex interplay between genetic, epigenetic and environmental factors. While the major environmental factors, diet and activity level, are well known, identification of the genetic factors has been a challenge. However, recent years have seen an explosion of genetic variants in risk and protection of T2D due to the technical development that has allowed genome-wide association studies and next-generation sequencing. Today, more than 120 variants have been convincingly replicated for association with T2D and many more with diabetes-related traits. Still, these variants only explain a small proportion of the total heritability of T2D. In this review, we address the possibilities to elucidate the genetic landscape of T2D as well as discuss pitfalls with current strategies to identify the elusive unknown heritability including the possibility that our definition of diabetes and its subgroups is imprecise and thereby makes the identification of genetic causes difficult.
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Affiliation(s)
- Rashmi B Prasad
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University Diabetes Centre, Lund University, CRC, Skåne University Hospital SUS, SE-205 02 Malmö, Sweden.
| | - Leif Groop
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University Diabetes Centre, Lund University, CRC, Skåne University Hospital SUS, SE-205 02 Malmö, Sweden.
- Finnish Institute of Molecular Medicine (FIMM), Helsinki University, Helsinki 00014, Finland.
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Marshall BA, Green RP, Wambach J, White NH, Remedi MS, Nichols CG. Remission of severe neonatal diabetes with very early sulfonylurea treatment. Diabetes Care 2015; 38:e38-9. [PMID: 25715421 PMCID: PMC4876698 DOI: 10.2337/dc14-2124] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Bess A Marshall
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO Department of Cell Biology, Washington University School of Medicine, St. Louis, MO
| | | | - Jennifer Wambach
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
| | - Neil H White
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
| | - Maria S Remedi
- Department of Cell Biology, Washington University School of Medicine, St. Louis, MO
| | - Colin G Nichols
- Department of Cell Biology, Washington University School of Medicine, St. Louis, MO
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17
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Chan KHK, Chacko SA, Song Y, Cho M, Eaton CB, Wu WCH, Liu S. Genetic variations in magnesium-related ion channels may affect diabetes risk among African American and Hispanic American women. J Nutr 2015; 145:418-24. [PMID: 25733456 PMCID: PMC4336527 DOI: 10.3945/jn.114.203489] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Prospective studies consistently link low magnesium intake to higher type 2 diabetes (T2D) risk. OBJECTIVE We examined the association of common genetic variants [single nucleotide polymorphisms (SNPs)] in genes related to magnesium homeostasis with T2D risk and potential interactions with magnesium intake. METHODS Using the Women's Health Initiative-SNP Health Association Resource (WHI-SHARe) study, we identified 17 magnesium-related ion channel genes (583 SNPs) and examined their associations with T2D risk in 7287 African-American (AA; n = 1949 T2D cases) and 3285 Hispanic-American (HA; n = 611 T2D cases) postmenopausal women. We performed both single- and multiple-locus haplotype analyses. RESULTS Among AA women, carriers of each additional copy of SNP rs6584273 in cyclin mediator 1 (CNNM1) had 16% lower T2D risk [OR: 0.84; false discovery rate (FDR)-adjusted P = 0.02]. Among HA women, several variants were significantly associated with T2D risk, including rs10861279 in solute carrier family 41 (anion exchanger), member 2 (SLC41A2) (OR: 0.54; FDR-adjusted P = 0.04), rs7174119 in nonimprinted in Prader-Willi/Angelman syndrome 1 (NIPA1) (OR: 1.27; FDR-adjusted P = 0.04), and 2 SNPs in mitochondrial RNA splicing 2 (MRS2) (rs7738943: OR = 1.55, FDR-adjusted P = 0.01; rs1056285: OR = 1.48, FDR-adjusted P = 0.02). Even with the most conservative Bonferroni adjustment, two 2-SNP-haplotypes in SLC41A2 and MRS2 region were significantly associated with T2D risk (rs12582312-rs10861279: P = 0.0006; rs1056285-rs7738943: P = 0.002). Among women with magnesium intake in the lowest 30% (AA: ≤0.164 g/d; HA: ≤0.185 g/d), 4 SNP signals were strengthened [rs11590362 in claudin 19 (CLDN19), rs823154 in SLC41A1, rs5929706 and rs5930817 in membra; HA: ≥0.313 g/d), rs6584273 in CNNM1 (OR: 0.71; FDR-adjusted P = 0.04) and rs1800467 in potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11) (OR: 2.50; FDR-adjusted P = 0.01) were significantly associated with T2D risk. CONCLUSIONS Our findings suggest important associations between genetic variations in magnesium-related ion channel genes and T2D risk in AA and HA women that vary by amount of magnesium intake.
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Affiliation(s)
| | - Sara A Chacko
- Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Yiqing Song
- Department of Epidemiology, Indiana University Richard M. Fairbanks School of Public Health, Indianapolis, IN; Departments of
| | - Michele Cho
- Medicine and,Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA
| | - Charles B Eaton
- Family Medicine,,Epidemiology, and,Center for Primary Care and Prevention, Memorial Hospital of Rhode Island, Pawtucket, RI
| | - Wen-Chih H Wu
- Medicine, Warren Alpert Medical School, Brown University, Providence, RI;,Vascular Research Laboratory, Providence US Department of Veterans Affairs Medical Center, Providence, RI; and
| | - Simin Liu
- Department of Epidemiology, and Departments of Medicine, Warren Alpert Medical School, Brown University, Providence, RI; Medicine and Obstetrics and Gynecology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA; Division of Endocrinology, Rhode Island Hospital, Providence, RI
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18
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Bennett JT, Vasta V, Zhang M, Narayanan J, Gerrits P, Hahn SH. Molecular genetic testing of patients with monogenic diabetes and hyperinsulinism. Mol Genet Metab 2015; 114:451-8. [PMID: 25555642 PMCID: PMC7852340 DOI: 10.1016/j.ymgme.2014.12.304] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 12/13/2014] [Accepted: 12/13/2014] [Indexed: 02/06/2023]
Abstract
Genetic sequencing has become a critical part of the diagnosis of certain forms of pancreatic beta cell dysfunction. Despite great advances in the speed and cost of DNA sequencing, determining the pathogenicity of variants remains a challenge, and requires sharing of sequence and phenotypic data between laboratories. We reviewed all diabetes and hyperinsulinism-associated molecular testing done at the Seattle Children's Molecular Genetics Laboratory from 2009 to 2013. 331 probands were referred to us for molecular genetic sequencing for Neonatal Diabetes (NDM), Maturity-Onset Diabetes of the Young (MODY), or Congenital Hyperinsulinism (CHI) during this period. Reportable variants were identified in 115 (35%) patients with 91 variants in one of 6 genes: HNF1A, GCK, HNF4A, ABCC8, KCNJ11, or INS. In addition to identifying 23 novel variants, we identified unusual mechanisms of inheritance, including mosaic and digenic MODY presentations. Re-analysis of all reported variants using more recently available databases led to a change in variant interpretation from the original report in 30% of cases. These results represent a resource for molecular testing of monogenic forms of diabetes and hyperinsulinism, providing a mutation spectrum for these disorders in a large North American cohort. In addition, they highlight the importance of periodic review of molecular testing results.
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Affiliation(s)
- James T Bennett
- Department of Pediatrics, University of Washington School of Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Valeria Vasta
- Department of Pediatrics, University of Washington School of Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Min Zhang
- Department of Pediatrics, University of Washington School of Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Jaya Narayanan
- Department of Pediatrics, University of Washington School of Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Peter Gerrits
- Department of Pediatric Endocrinology, Beaumont Children's Hospital, Royal Oak, MI 48073, USA
| | - Si Houn Hahn
- Department of Pediatrics, University of Washington School of Medicine, Seattle Children's Hospital, Seattle, WA 98105, USA.
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Brue T, Quentien MH, Khetchoumian K, Bensa M, Capo-Chichi JM, Delemer B, Balsalobre A, Nassif C, Papadimitriou DT, Pagnier A, Hasselmann C, Patry L, Schwartzentruber J, Souchon PF, Takayasu S, Enjalbert A, Van Vliet G, Majewski J, Drouin J, Samuels ME. Mutations in NFKB2 and potential genetic heterogeneity in patients with DAVID syndrome, having variable endocrine and immune deficiencies. BMC MEDICAL GENETICS 2014; 15:139. [PMID: 25524009 PMCID: PMC4411703 DOI: 10.1186/s12881-014-0139-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 12/11/2014] [Indexed: 01/09/2023]
Abstract
Background DAVID syndrome is a rare condition combining anterior pituitary hormone deficiency with common variable immunodeficiency. NFKB2 mutations have recently been identified in patients with ACTH and variable immunodeficiency. A similar mutation was previously found in Nfkb2 in the immunodeficient Lym1 mouse strain, but the effect of the mutation on endocrine function was not evaluated. Methods We ascertained six unrelated DAVID syndrome families. We performed whole exome and traditional Sanger sequencing to search for causal genes. Lym1 mice were examined for endocrine developmental anomalies. Results Mutations in the NFKB2 gene were identified in three of our families through whole exome sequencing, and in a fourth by direct Sanger sequencing. De novo origin of the mutations could be demonstrated in three of the families. All mutations lie near the C-terminus of the protein-coding region, near signals required for processing of NFΚB2 protein by the alternative pathway. Two of the probands had anatomical pituitary anomalies, and one had growth and thyroid hormone as well as ACTH deficiency; these findings have not been previously reported. Two children of one of the probands carried the mutation and have to date exhibited only an immune phenotype. No mutations were found near the C-terminus of NFKB2 in the remaining two probands; whole exome sequencing has been performed for one of these. Lym1 mice, carrying a similar Nfkb2 C-terminal mutation, showed normal pituitary anatomy and expression of proopiomelanocortin (POMC). Conclusions We confirm previous findings that mutations near the C-terminus of NFKB2 cause combined endocrine and immunodeficiencies. De novo status of the mutations was confirmed in all cases for which both parents were available. The mutations are consistent with a dominant gain-of-function effect, generating an unprocessed NFKB2 super-repressor protein. We expand the potential phenotype of such NFKB2 mutations to include additional pituitary hormone deficiencies as well as anatomical pituitary anomalies. The lack of an observable endocrine phenotype in Lym1 mice suggests that the endocrine component of DAVID syndrome is either not due to a direct role of NFKB pathways on pituitary development, or else that human and mouse pituitary development differ in its requirements for NFKB pathway function. Electronic supplementary material The online version of this article (doi:10.1186/s12881-014-0139-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Thierry Brue
- Aix-Marseille University, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M), Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7286, Faculté de Médecine de Marseille, 13344, Marseille, France. .,Assistance Publique-Hôpitaux de Marseille (APHM), Department of Endocrinology, Centre de Référence des Maladies Rares d'Origine Hypophysaire, Hôpital de la Timone, 13005, Marseille, France.
| | - Marie-Hélène Quentien
- Aix-Marseille University, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M), Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7286, Faculté de Médecine de Marseille, 13344, Marseille, France. .,Assistance Publique-Hôpitaux de Marseille (APHM), Department of Endocrinology, Centre de Référence des Maladies Rares d'Origine Hypophysaire, Hôpital de la Timone, 13005, Marseille, France.
| | - Konstantin Khetchoumian
- Laboratoire de Génétique moléculaire, Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada.
| | - Marco Bensa
- Ospedale Bufalini, Department of Paediatrics, Cesena, FC, Italy.
| | | | - Brigitte Delemer
- Departments of Endocrinology and of Pediatrics, Centre Hospitalier Robert Debré, 51092, Reims, France.
| | - Aurelio Balsalobre
- Laboratoire de Génétique moléculaire, Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada.
| | - Christina Nassif
- Centre de Recherche du CHU Ste-Justine, 3175 Cote Ste-Catherine, Montreal, QC, Canada.
| | - Dimitris T Papadimitriou
- Department of Pediatric-Adolescent Endocrinology and Diabetes, Athens Medical Center, Athens, Greece.
| | - Anne Pagnier
- Clinique universitaire de pédiatrie, CHU de Grenoble, Grenoble, France.
| | - Caroline Hasselmann
- Centre de Recherche du CHU Ste-Justine, 3175 Cote Ste-Catherine, Montreal, QC, Canada.
| | - Lysanne Patry
- Centre de Recherche du CHU Ste-Justine, 3175 Cote Ste-Catherine, Montreal, QC, Canada.
| | | | - Pierre-François Souchon
- Departments of Endocrinology and of Pediatrics, Centre Hospitalier Robert Debré, 51092, Reims, France.
| | - Shinobu Takayasu
- Laboratoire de Génétique moléculaire, Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada.
| | - Alain Enjalbert
- Aix-Marseille University, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M), Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7286, Faculté de Médecine de Marseille, 13344, Marseille, France. .,Assistance Publique-Hôpitaux de Marseille (APHM), Department of Endocrinology, Centre de Référence des Maladies Rares d'Origine Hypophysaire, Hôpital de la Timone, 13005, Marseille, France.
| | - Guy Van Vliet
- Endocrinology Service and Research Center, Department of Pediatrics, CHU Ste-Justine, University of Montreal, Montreal, QC, Canada.
| | - Jacek Majewski
- Department of Human Genetics, McGill University, Montreal, QC, Canada.
| | - Jacques Drouin
- Laboratoire de Génétique moléculaire, Institut de recherches cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, QC, H2W 1R7, Canada.
| | - Mark E Samuels
- Centre de Recherche du CHU Ste-Justine, 3175 Cote Ste-Catherine, Montreal, QC, Canada. .,Department of Medicine, University of Montreal, Montreal, QC, Canada.
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Craig ME, Jefferies C, Dabelea D, Balde N, Seth A, Donaghue KC. ISPAD Clinical Practice Consensus Guidelines 2014. Definition, epidemiology, and classification of diabetes in children and adolescents. Pediatr Diabetes 2014; 15 Suppl 20:4-17. [PMID: 25182305 DOI: 10.1111/pedi.12186] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 06/16/2014] [Indexed: 12/20/2022] Open
Affiliation(s)
- Maria E Craig
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead and University of Sydney, Sydney, Australia; School of Women's and Children's Health, University of New South Wales, Sydney, Australia
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Hassanali N, De Silva NMG, Robertson N, Rayner NW, Barrett A, Bennett AJ, Groves CJ, Matthews DR, Katulanda P, Frayling TM, McCarthy MI. Evaluation of common type 2 diabetes risk variants in a South Asian population of Sri Lankan descent. PLoS One 2014; 9:e98608. [PMID: 24926958 PMCID: PMC4057178 DOI: 10.1371/journal.pone.0098608] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 05/05/2014] [Indexed: 01/11/2023] Open
Abstract
INTRODUCTION Most studies seeking common variant associations with type 2 diabetes (T2D) have focused on individuals of European ancestry. These discoveries need to be evaluated in other major ancestral groups, to understand ethnic differences in predisposition, and establish whether these contribute to variation in T2D prevalence and presentation. This study aims to establish whether common variants conferring T2D-risk in Europeans contribute to T2D-susceptibility in the South Asian population of Sri Lanka. METHODOLOGY Lead single nucleotide polymorphism (SNPs) at 37 T2D-risk loci attaining genome-wide significance in Europeans were genotyped in 878 T2D cases and 1523 normoglycaemic controls from Sri Lanka. Association testing was performed by logistic regression adjusting for age and sex and by the Cochran-Mantel-Haenszel test after stratifying according to self-identified ethnolinguistic subgroup. A weighted genetic risk score was generated to examine the combined effect of these SNPs on T2D-risk in the Sri Lankan population. RESULTS Of the 36 SNPs passing quality control, sixteen showed nominal (p<0.05) association in Sri Lankan samples, fifteen of those directionally-consistent with the original signal. Overall, these association findings were robust to analyses that accounted for membership of ethnolinguistic subgroups. Overall, the odds ratios for 31 of the 36 SNPs were directionally-consistent with those observed in Europeans (p = 3.2×10(-6)). Allelic odds ratios and risk allele frequencies in Sri Lankan subjects were not systematically different to those reported in Europeans. Genetic risk score and risk of T2D were strongly related in Sri Lankans (per allele OR 1.10 [95%CI 1.08-1.13], p = 1.2×10(-17)). CONCLUSION Our data indicate that most T2D-risk variants identified in Europeans have similar effects in South Asians from Sri Lanka, and that systematic difference in common variant associations are unlikely to explain inter-ethnic differences in prevalence or presentation of T2D.
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Affiliation(s)
- Neelam Hassanali
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - N. Maneka G. De Silva
- Genetics of Complex Traits, University of Exeter Medical School, Exeter, United Kingdom
| | - Neil Robertson
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - N. William Rayner
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Amy Barrett
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Amanda J. Bennett
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - Christopher J. Groves
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
| | - David R. Matthews
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Harris Manchester College, University of Oxford, Oxford, United Kingdom
| | - Prasad Katulanda
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Timothy M. Frayling
- Genetics of Complex Traits, University of Exeter Medical School, Exeter, United Kingdom
| | - Mark I. McCarthy
- Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford National Institute for Health Research Biomedical Research Centre, Churchill Hospital, Oxford, United Kingdom
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Bee YM, Zhao Y, Ellard S, Hattersley AT, Yap F. Permanent neonatal diabetes in siblings with novel C109Y INS mutation transmitted by an unaffected parent with somatic mosaicism. Pediatr Diabetes 2014; 15:324-8. [PMID: 24279684 DOI: 10.1111/pedi.12104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/14/2013] [Accepted: 10/23/2013] [Indexed: 11/29/2022] Open
Abstract
Mutations involving the insulin (INS) gene are a common cause of permanent neonatal diabetes (PND). Although INS mutations typically occur de novo and germline INS mutations transmitted to offspring by unaffected parents has been described, somatic mosaicism in a parent with an INS mutation has not been previously reported. We describe two siblings (one brother and one sister) with PND (26- and 19-yr old diagnosed at 3 and 7 months old, respectively), whose parents were unaffected. We performed genetic analysis of leukocyte DNA for this family. Both patients were found to carry the novel heterozygous c.326G>A substitution in exon 3 of INS, resulting in a p.C109Y change of the insulin protein. Analyses of leukocyte DNA from the parents revealed low level mutation in the sequencing trace of the father, raising the possibility of somatic mosaicism. Real-time polymerase chain reaction (PCR) analysis showed he had approximately 73% of the mutant allele relative to his affected son. This first report of somatic mosaicism in an unaffected parent with an INS mutation suggests that parental mosaicism may be responsible for the transmission of PND in patients with de novo INS mutations. As such, appropriate counseling for recurrent risks should be considered and we recommend that molecular genetic testing for future siblings at birth should be offered to the parents of children with INS mutation.
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Affiliation(s)
- Yong Mong Bee
- Department of Endocrinology, Singapore General Hospital, Singapore, Singapore
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23
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Fraser CS, Rubio-Cabezas O, Littlechild JA, Ellard S, Hattersley AT, Flanagan SE. Amino acid properties may be useful in predicting clinical outcome in patients with Kir6.2 neonatal diabetes. Eur J Endocrinol 2012; 167:417-21. [PMID: 22648966 DOI: 10.1530/eje-12-0227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Mutations in the KCNJ11 gene, which encodes the Kir6.2 subunit of the β-cell K(ATP) channel, are a common cause of neonatal diabetes. The diabetes may be permanent neonatal diabetes mellitus (PNDM) or transient neonatal diabetes mellitus (TNDM), and in ≈ 20% of patients, neurological features are observed. A correlation between the position of the mutation in the protein and the clinical phenotype has previously been described; however, recently, this association has become less distinct with different mutations at the same residues now reported in patients with different diabetic and/or neurological phenotypes. METHODS We identified from the literature, and our unpublished series, KCNJ11 mutations that affected residues harbouring various amino acid substitutions (AAS) causing differences in diabetic or neurological status. Using the Grantham amino acid scoring system, we investigated whether the difference in properties between the wild-type and the different AAS at the same residue could predict phenotypic severity. RESULTS Pair-wise analysis demonstrated higher Grantham scores for mutations causing PNDM or diabetes with neurological features when compared with mutations affecting the same residue that causes TNDM (P=0.013) or diabetes without neurological features (P=0.016) respectively. In just five of the 25 pair-wise analyses, a lower Grantham score was observed for the more severe phenotype. In each case, the wild-type residue was glycine, the simplest amino acid. CONCLUSION This study demonstrates the importance of the specific AAS in determining phenotype and highlights the potential utility of the Grantham score for predicting phenotypic severity for novel KCNJ11 mutations affecting previously mutated residues.
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Affiliation(s)
- Clementine S Fraser
- Department of Molecular Genetics, Institute of Biomedical and Clinical Science, Peninsula Medical School, University of Exeter, Barrack Road, Exeter EX2 5DW, UK
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Detection of KCNJ11 gene mutations in a family with neonatal diabetes mellitus: implications for therapeutic management of family members with long-standing disease. Mol Diagn Ther 2012; 16:109-14. [PMID: 22471336 DOI: 10.1007/bf03256435] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND Activating mutations of potassium inwardly-rectifying channel, subfamily J, member 11 (KCNJ11), which encodes Kir6.2 (beta-cell adenosine triphosphate-sensitive potassium [K(ATP)] channel subunit), have been associated with neonatal diabetes mellitus (NDM) in different studies. Treatment with oral sulfonylureas in place of exogenous insulin injections results in improved glycemic control in most patients carrying these mutations. Exploration of genetic causes of NDM occurring before the age of 6 months has been proposed as an important issue in identification of monogenic forms of diabetes, which might be critical in their therapeutic management, as a consequence. METHODS Mutation screening of the KCNJ11 gene was carried out using PCR amplification followed by direct sequencing in three family members: the proband, ND1, diagnosed at 40 days of age (current age 7 years); his sibling, ND2, diagnosed at 2 years of age (current age 14 years); and their father, ND3, diagnosed at 15 years of age (current age 35 years), who had been exclusively treated with insulin. The effect of the E227K mutation was also examined in a homology model of Kir6.2. RESULTS Our results revealed the presence of the heterozygous missense mutation c. 679 G/A (E227K) in all three patients, who were all able to successfully transfer from insulin injections to an oral sulfonylurea, with improved glycemic control. CONCLUSION We found that three members of a family with highly variable age of onset of insulin-treated diabetes, diagnosed at 40 days, 2 years, and 15 years of age, all carried the E227K mutation in KCNJ11 and could switch to an oral sulfonylurea. This mutation has been previously reported in patients with permanent and transient NDM, as well as later-onset diabetes; this report adds to the variability in phenotypic presentation and further supports genetic testing in all diabetic members of any family affected by NDM.
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Mıhçı E, Türkkahraman D, Ellard S, Akçurin S, Bircan İ. Wolcott-Rallison syndrome due to a novel mutation (R491X) in EIF2AK3 gene. J Clin Res Pediatr Endocrinol 2012; 4:101-3. [PMID: 22672868 PMCID: PMC3386768 DOI: 10.4274/jcrpe.619] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [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
Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by early-onset diabetes, spondyloepiphyseal dysplasia, tendency to skeletal fractures secondary to osteopenia, and growth retardation. Mutations in the eukaryotic translation initiation factor 2α kinase (EIF2AK3) gene are responsible for this disorder. Here, we describe a boy with neonatal diabetes, diagnosed at 2 months of age, who developed severe growth retardation and a skeletal fracture during the follow-up period. The patient's skeletal X-ray revealed findings of skeletal dysplasia. A clinical diagnosis of WRS was confirmed by the identification of a novel homozygous nonsense mutation (R491X) in exon 9 of the EIF2AK3 gene. The aim of this report is to raise the awareness for Wolcott-Rallison syndrome in cases presenting with isolated neonatal diabetes. This patient demonstrates that the other findings of this syndrome might be obscured by a diagnosis of isolated neonatal diabetes.
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Affiliation(s)
- Ercan Mıhçı
- Akdeniz University School of Medicine, Department of Pediatrics, Division of Clinical Genetics, Antalya, Turkey
| | - Doğa Türkkahraman
- Antalya Education and Research Hospital, Department of Pediatric Endocrinology, Antalya, Turkey
| | - Sian Ellard
- Institute of Biomedical Science, Peninsula Medical School, University of Exeter, UK
| | - Sema Akçurin
- Akdeniz University School of Medicine, Department of Pediatric Endocrinology, Antalya, Turkey
| | - İffet Bircan
- Akdeniz University School of Medicine, Department of Pediatric Endocrinology, Antalya, Turkey
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Abstract
Neonatal diabetes mellitus (NDM) is the term commonly used to describe diabetes with onset before 6 months-of-age. It occurs in approximately one out of every 100,000-300,000 live births. Although this term encompasses diabetes of any etiology, it is recognized that NDM diagnosed before 6 months-of-age is most often monogenic in nature. Clinically, NDM subgroups include transient (TNDM) and permanent NDM (PNDM), as well as syndromic cases of NDM. TNDM often develops within the first few weeks of life and remits by a few months of age. However, relapse occurs in 50% of cases, typically in adolescence or adulthood. TNDM is most frequently caused by abnormalities in the imprinted region of chromosome 6q24, leading to overexpression of paternally derived genes. Mutations in KCNJ11 and ABCC8, encoding the two subunits of the adenosine triphosphate-sensitive potassium channel on the β-cell membrane, can cause TNDM, but more often result in PNDM. NDM as a result of mutations in KCNJ11 and ABCC8 often responds to sulfonylureas, allowing transition from insulin therapy. Mutations in other genes important to β-cell function and regulation, and in the insulin gene itself, also cause NDM. In 40% of NDM cases, the genetic cause remains unknown. Correctly identifying monogenic NDM has important implications for appropriate treatment, expected disease course and associated conditions, and genetic testing for at-risk family members. Early recognition of monogenic NDM allows for the implementation of appropriate therapy, leading to improved outcomes and potential societal cost savings. (J Diabetes Invest, doi:10.1111/j.2040-1124.2011.00106.x, 2011).
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Affiliation(s)
| | | | - Graeme I Bell
- Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, Chicago, Illinois, USA
| | - Louis H Philipson
- Departments of Pediatrics
- Medicine, Section of Adult and Pediatric Endocrinology, Diabetes and Metabolism, The University of Chicago, Chicago, Illinois, USA
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Quan Y, Barszczyk A, Feng ZP, Sun HS. Current understanding of K ATP channels in neonatal diseases: focus on insulin secretion disorders. Acta Pharmacol Sin 2011; 32:765-80. [PMID: 21602835 PMCID: PMC4009965 DOI: 10.1038/aps.2011.57] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/13/2011] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (K(ATP)) channels are cell metabolic sensors that couple cell metabolic status to electric activity, thus regulating many cellular functions. In pancreatic beta cells, K(ATP) channels modulate insulin secretion in response to fluctuations in plasma glucose level, and play an important role in glucose homeostasis. Recent studies show that gain-of-function and loss-of-function mutations in K(ATP) channel subunits cause neonatal diabetes mellitus and congenital hyperinsulinism respectively. These findings lead to significant changes in the diagnosis and treatment for neonatal insulin secretion disorders. This review describes the physiological and pathophysiological functions of K(ATP) channels in glucose homeostasis, their specific roles in neonatal diabetes mellitus and congenital hyperinsulinism, as well as future perspectives of K(ATP) channels in neonatal diseases.
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Affiliation(s)
- Yi Quan
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Andrew Barszczyk
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Zhong-ping Feng
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
| | - Hong-shuo Sun
- Departments of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Surgery, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Departments of Pharmacology, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
- Institute of Medical Science, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada, M5S 1A8
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Rubio-Cabezas O, Klupa T, Malecki MT. Permanent neonatal diabetes mellitus--the importance of diabetes differential diagnosis in neonates and infants. Eur J Clin Invest 2011; 41:323-33. [PMID: 21054355 DOI: 10.1111/j.1365-2362.2010.02409.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND The differential diagnosis of various types and forms of diabetes is of great practical importance. This is particularly true for monogenic disease forms, where some spectacular applications of pharmacogenetics have recently been described. DESIGN For many years the distinct character of diabetes diagnosed in the first weeks and months of life remained unnoticed. The results of the search for type 1 diabetes-related autoantibodies, description of the HLA haplotypes distribution and analysis of clinical features in patients diagnosed in the first 6 months of life provided the initial evidence that the etiology of their disease might be different from that of autoimmune diabetes. RESULTS Over the last decade, mutations in about a dozen of genes have been linked to the development of Permanent Neonatal Diabetes Mellitus (PNDM). The most frequent causes of PNDM are heterozygous mutations in the KCNJ11, INS and ABCC8 genes. Although PNDM is a rare phenomenon (one case in about 200,000 live births), this discovery has had a large impact on clinical practice as most carriers of KCNJ11 and ABCC8 gene mutations have been switched from insulin to oral sulphonylureas with an improvement in glycemic control. In this review we summarize the practical aspects of diabetes differential diagnosis in neonates and infants. CONCLUSIONS Genetic testing should be advised in all subjects with PNDM as it may influence medical care in subjects with these monogenic forms of early onset diabetes.
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Affiliation(s)
- Oscar Rubio-Cabezas
- Institute of Biomedical and Clinical Science, Peninsula Medical School, Universities of Exeter & Plymouth, Exeter, UK
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29
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Ioannou YS, Ellard S, Hattersley A, Skordis N. KCNJ11 activating mutations cause both transient and permanent neonatal diabetes mellitus in Cypriot patients. Pediatr Diabetes 2011; 12:133-7. [PMID: 21352428 DOI: 10.1111/j.1399-5448.2010.00743.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Heterozygous mutations of the KCNJ11 gene encoding the Kir6.2 subunit of the ATP-sensitive potassium channel (K(ATP) channel) of the pancreatic β-cell cause diabetes in about 30-60% of all permanent neonatal diabetes mellitus cases diagnosed before 6 months of age. The K(ATP) channel plays an essential role in the regulation of the electrical status of the membrane through which the secretion of insulin is activated. Transient neonatal diabetes mellitus due to KCNJ11 mutations is less frequent than abnormalities affecting the imprinted region of chromosome 6q24. We studied the genetic basis of two Cypriot patients who developed diabetes before 6 months of age. They both carried mutations of the KCNJ11 gene. The R201H mutation was identified in a patient who developed hyperglycemia and ketoacidosis at the age of 40 d and was successfully transferred to sulphonylureas which activate the channel through an ATP independent route. The R50Q mutation was identified in a child diagnosed at day 45 after birth with remission of his diabetes at 9 months of age. The same defect was identified both in his asymptomatic mother and the recently diagnosed 'type 2' diabetic maternal grandmother. The remission-relapse mechanism in cases of transient neonatal diabetes is not known. Nevertheless, it is possible that the residue of the mutation within the Kir6.2 molecule is associated with the sensitivity to ATP reflecting to the severity of the diabetic phenotype.
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30
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Sang Y, Ni G, Gu Y, Liu M. AV59M KCNJ11 gene mutation leading to intermediate DEND syndrome in a Chinese child. J Pediatr Endocrinol Metab 2011; 24:763-6. [PMID: 22145471 DOI: 10.1515/jpem.2011.258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Heterozygous activating mutations in the KCNJ11 gene can cause permanent and transient neonatal diabetes. In the present study, we sequenced the KCNJ11 gene in a Chinese boy diagnosed with permanent neonatal diabetes mellitus (PNDM) and also in his parents. A heterozygous 175G > A (V59M) mutation was identified in the patient, while no KCNJ11 gene mutations were found in his parents, indicating that this mutation is de novo. The patient with the V59M mutation successfully switched from insulin injections to oral glibenclamide; 2 years of follow-up revealed that the patient had intermediate developmental delay, epilepsy and neonatal diabetes (DEND) syndrome. This is the first patient who is reported to have iDEND syndrome due to KCNJ11 V59M mutation in China.
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Affiliation(s)
- Yanmei Sang
- Department of Endocrinology, National Key Discipline of Pediatrics (Capital Medical University), Ministry of Education, Beijing Children's Hospital, Capital Medical University, Beijing 100045, China.
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31
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Lang V, Light PE. The molecular mechanisms and pharmacotherapy of ATP-sensitive potassium channel gene mutations underlying neonatal diabetes. Pharmgenomics Pers Med 2010; 3:145-61. [PMID: 23226049 PMCID: PMC3513215 DOI: 10.2147/pgpm.s6969] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Indexed: 12/14/2022] Open
Abstract
Neonatal diabetes mellitus (NDM) is a monogenic disorder caused by mutations in genes involved in regulation of insulin secretion from pancreatic β-cells. Mutations in the KCNJ11 and ABCC8 genes, encoding the adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channel Kir6.2 and SUR1 subunits, respectively, are found in ∼50% of NDM patients. In the pancreatic β-cell, K(ATP) channel activity couples glucose metabolism to insulin secretion via cellular excitability and mutations in either KCNJ11 or ABCC8 genes alter K(ATP) channel activity, leading to faulty insulin secretion. Inactivation mutations decrease K(ATP) channel activity and stimulate excessive insulin secretion, leading to hyperinsulinism of infancy. In direct contrast, activation mutations increase K(ATP) channel activity, resulting in impaired insulin secretion, NDM, and in severe cases, developmental delay and epilepsy. Many NDM patients with KCNJ11 and ABCC8 mutations can be successfully treated with sulfonylureas (SUs) that inhibit the K(ATP) channel, thus replacing the need for daily insulin injections. There is also strong evidence indicating that SU therapy ameliorates some of the neurological defects observed in patients with more severe forms of NDM. This review focuses on the molecular and cellular mechanisms of mutations in the K(ATP) channel that underlie NDM. SU pharmacogenomics is also discussed with respect to evaluating whether patients with certain K(ATP) channel activation mutations can be successfully switched to SU therapy.
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Affiliation(s)
- Veronica Lang
- Department of Pharmacology and Alberta Diabetes Institute, Faculty of Medicine and Dentistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Peter E Light
- Department of Pharmacology and Alberta Diabetes Institute, Faculty of Medicine and Dentistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada
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32
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Edghill EL, Flanagan SE, Ellard S. Permanent neonatal diabetes due to activating mutations in ABCC8 and KCNJ11. Rev Endocr Metab Disord 2010; 11:193-8. [PMID: 20922570 DOI: 10.1007/s11154-010-9149-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The ATP-sensitive potassium (K(ATP)) channel is composed of two subunits SUR1 and Kir6.2. The channel is key for glucose stimulated insulin release from the pancreatic beta cell. Activating mutations have been identified in the genes encoding these subunits, ABCC8 and KCNJ11, and account for approximately 40% of permanent neonatal diabetes cases. The majority of patients with a K(ATP) mutation present with isolated diabetes however some have presented with the Developmental delay, Epilepsy and Neonatal Diabetes syndrome. This review focuses on mutations in the K(ATP) channel which result in permanent neonatal diabetes, we review the clinical and functional effects as well as the implications for treatment.
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MESH Headings
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- ATP-Binding Cassette Transporters/physiology
- Diabetes Mellitus/congenital
- Diabetes Mellitus/genetics
- Diabetes Mellitus/therapy
- Genetic Association Studies
- Humans
- Infant, Newborn
- Infant, Newborn, Diseases/genetics
- Infant, Newborn, Diseases/therapy
- KATP Channels/genetics
- KATP Channels/metabolism
- KATP Channels/physiology
- Models, Biological
- Mutation/physiology
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Potassium Channels, Inwardly Rectifying/physiology
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Receptors, Drug/physiology
- Sulfonylurea Receptors
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Affiliation(s)
- Emma L Edghill
- Institute of Biomedical and Clinical Science, Peninsula College of Medicine and Dentistry, University of Exeter, Barrack Road, Exeter, UK
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33
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Abstract
Transient Neonatal Diabetes (type 1) is the commonest cause of diabetes presenting in the first week of life. The majority of infants recover by 3 months of age but are predisposed to developing type 2 diabetes in later life. It is associated with low birth weight but rapid catch up by 1 year of life. The condition is usually due to genetic or epigenetic aberrations at an imprinted locus on chromosome 6q24 and can be sporadic or inherited. Early diagnosis alters medical treatment strategies and differentiates it from other types of early onset diabetes. In some individuals, diabetes may be the initial presentation of a more complex imprinting disorder due to recessive mutations in the gene ZFP57 and may be associated with other developmental problems.
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MESH Headings
- Chromosome Disorders/complications
- Chromosome Disorders/diagnosis
- Chromosome Disorders/therapy
- Chromosomes, Human, Pair 6
- Diabetes Mellitus, Type 1/congenital
- Diabetes Mellitus, Type 1/diagnosis
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/therapy
- Epigenesis, Genetic/physiology
- Humans
- Infant, Newborn
- Infant, Newborn, Diseases/diagnosis
- Infant, Newborn, Diseases/etiology
- Infant, Newborn, Diseases/genetics
- Infant, Newborn, Diseases/therapy
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Affiliation(s)
- I Karen Temple
- Academic Unit of Genetic Medicine, Princess Anne Hospital, Coxford Road, Southampton, SO16 5YA, UK.
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34
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Chang B, Momoi N, Shan L, Mitomo M, Aoyagi Y, Endo K, Takeda I, Chen R, Xing Y, Yu X, Watanabe S, Yoshida T, Kanegane H, Tsubata S, Bowles NE, Ichida F, Miyawaki T. Gonadal mosaicism of a TAZ (G4.5) mutation in a Japanese family with Barth syndrome and left ventricular noncompaction. Mol Genet Metab 2010; 100:198-203. [PMID: 20303308 DOI: 10.1016/j.ymgme.2010.02.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 02/24/2010] [Accepted: 02/25/2010] [Indexed: 11/18/2022]
Abstract
TAZ (G4.5) was initially identified as the gene associated with Barth syndrome and left ventricular noncompaction (LVNC). The purpose of this study was to investigate patients with LVNC for disease-causing mutations in TAZ. In 124 Japanese patients, including 50 families, mutation analysis of TAZ was performed using DNA sequencing. A splice donor mutation was identified in two brothers with Barth syndrome and LVNC, and a sister who was asymptomatic. However, the variant was not identified in either parent or the maternal grandparents, all of whom were asymptomatic. Due to the recurrent inheritance of this variant by each of the children we concluded that this was evidence of gonadal mosaicism in the obligate carrier mother, the first reported occurrence of this in Barth syndrome.
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Affiliation(s)
- Bo Chang
- Department of Pediatrics, Toyama University, Sugitani, Toyama, Japan
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35
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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: 1074] [Impact Index Per Article: 76.7] [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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36
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Abstract
PURPOSE OF REVIEW Here we give context to new data on neonatal diabetes mellitus, a rare group of insulin-requiring monogenic forms of diabetes presenting at birth or shortly thereafter. Genetic studies are critical in the diagnosis and treatment of these patients. The most common causes of neonatal diabetes are activating mutations in the two protein subunits of the ATP-sensitive potassium channel. These are responsible for about half of all cases of permanent neonatal diabetes and some cases of transient neonatal diabetes. Identification of these mutations allows patients treated with insulin to be transferred to sulfonylureas, but associated conditions and other causes must be considered. RECENT FINDINGS Recent data suggest that neonatal diabetes is more common than previously thought, with variable presentations. Continued studies provide further evidence for amelioration of developmental and neurological dysfunction exhibited by a significant proportion of patients. Abnormalities of chromosome 6q24 remain the most common cause of transient neonatal diabetes. Other causes of neonatal diabetes being studied include mutations in proinsulin, FOXP3 mutations in immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, homozygous glucokinase mutations, and Wolcott-Rallinson/EIF2AK3 diabetes. SUMMARY We still have much to learn about the different forms of neonatal diabetes, their associated clinical features, and the optimization of therapy using a growing number of available therapeutic agents.
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Affiliation(s)
- Siri Atma W Greeley
- Department of Medicine, The University of Chicago, Chicago, Illinois 60637, USA
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37
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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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38
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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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39
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Remedi MS, Kurata HT, Scott A, Wunderlich FT, Rother E, Kleinridders A, Tong A, Brüning JC, Koster JC, Nichols CG. Secondary consequences of beta cell inexcitability: identification and prevention in a murine model of K(ATP)-induced neonatal diabetes mellitus. Cell Metab 2009; 9:140-51. [PMID: 19187772 PMCID: PMC4793729 DOI: 10.1016/j.cmet.2008.12.005] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 11/09/2008] [Accepted: 12/05/2008] [Indexed: 10/21/2022]
Abstract
ATP-insensitive K(ATP) channel mutations cause neonatal diabetes mellitus (NDM). To explore the mechanistic etiology, we generated transgenic mice carrying an ATP-insensitive mutant K(ATP) channel subunit. Constitutive expression in pancreatic beta cells caused neonatal hyperglycemia and progression to severe diabetes and growth retardation, with loss of islet insulin content and beta cell architecture. Tamoxifen-induced expression in adult beta cells led to diabetes within 2 weeks, with similar secondary consequences. Diabetes was prevented by transplantation of normal islets under the kidney capsule. Moreover, the endogenous islets maintained normal insulin content and secretion in response to sulfonylureas, but not glucose, consistent with reduced ATP sensitivity of beta cell K(ATP) channels. In NDM, transfer to sulfonylurea therapy is less effective in older patients. This may stem from poor glycemic control or lack of insulin because glibenclamide treatment prior to tamoxifen induction prevented diabetes and secondary complications in mice but failed to halt disease progression after diabetes had developed.
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Affiliation(s)
- Maria Sara Remedi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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40
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Støy J, Greeley SAW, Paz VP, Ye H, Pastore AN, Skowron KB, Lipton RB, Cogen FR, Bell GI, Philipson LH. Diagnosis and treatment of neonatal diabetes: a United States experience. Pediatr Diabetes 2008; 9:450-9. [PMID: 18662362 PMCID: PMC2574846 DOI: 10.1111/j.1399-5448.2008.00433.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND/OBJECTIVE Mutations in KCNJ11, ABCC8, or INS are the cause of permanent neonatal diabetes mellitus in about 50% of patients diagnosed with diabetes before 6 months of age and in a small fraction of those diagnosed between 6 and 12 months. The aim of this study was to identify the genetic cause of diabetes in 77 consecutive patients referred to the University of Chicago with diabetes diagnosed before 1 yr of age. METHODS We used Oragene DNA Self-Collection kit to obtain a saliva sample for DNA. We sequenced the protein-coding regions of KCNJ11, ABCC8, and INS using standard methods. RESULTS We enrolled 32 patients diagnosed with diabetes before 6 months of age and 45 patients diagnosed between 6 and 12 months. We identified a mutation in KCNJ11 in 14 patients from 12 families and in INS in 7 patients from 4 families. Three of the patients with an INS mutation were diagnosed with diabetes between 6 and 12 months of age. Finally, we found that two patients had an abnormality of chromosome 6q24 associated with transient neonatal diabetes mellitus. CONCLUSIONS We were able to establish a genetic cause of diabetes in 63% of patients diagnosed with diabetes before 6 months of age and in 7% of patients diagnosed between 6 and 12 months. Genetic testing, which is critical for guiding appropriate management, should be considered in patients diagnosed with diabetes before 1 yr of age, especially if they are autoantibody negative, although the presence of autoantibodies does not rule out a monogenic cause.
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Affiliation(s)
- Julie Støy
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
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41
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Waterfield T, Gloyn AL. Monogenic β-cell dysfunction in children: clinical phenotypes, genetic etiology and mutational pathways. ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17455111.2.4.517] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Monogenic diabetes accounts for 1–2% of all cases of diabetes mellitus and presentation is often in childhood. Recognizing the clinical features of monogenic β-cell dysfunction prevents misdiagnosis and allows for more effective management and genetic counseling. Monogenic β-cell dysfunction is a diverse collection of clinical phenotypes underpinned by common mutational pathways. Mutations affecting the glycolytic glucokinase enzyme, the mitochondria, the KATP channels and transcription factors have been known for some time. Until recently, the role of endoplasmic reticulum stress was underestimated in the pathogenesis of diabetes. It is becoming increasingly clear that endoplasmic reticulum stress is an important etiological factor in the development of monogenic and polygenic diabetes. In this article, we aim to define the etiology of pediatric monogenic β-cell dysfunction and provide guidance on the investigation and management of children presenting with monogenic β-cell dysfunction.
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Affiliation(s)
- Thomas Waterfield
- Diabetes Research Laboratories, Oxford Centre for Diabetes Endocrinology & Metabolism, Churchill Hospital, Old Road, Headington, Oxford, OX3 7LJ, UK
| | - Anna L Gloyn
- Diabetes Research Laboratories, Oxford Centre for Diabetes Endocrinology & Metabolism, Churchill Hospital, Old Road, Headington, Oxford, OX3 7LJ, UK
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Murphy R, Ellard S, Hattersley AT. Clinical implications of a molecular genetic classification of monogenic beta-cell diabetes. ACTA ACUST UNITED AC 2008; 4:200-13. [PMID: 18301398 DOI: 10.1038/ncpendmet0778] [Citation(s) in RCA: 388] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 12/14/2007] [Indexed: 02/06/2023]
Abstract
Monogenic diabetes resulting from mutations that primarily reduce beta-cell function accounts for 1-2% of diabetes cases, although it is often misdiagnosed as either type 1 or type 2 diabetes. Knowledge of the genetic etiology of diabetes enables more-appropriate treatment, better prediction of disease progression, screening of family members and genetic counseling. We propose that the old clinical classifications of maturity-onset diabetes of the young and neonatal diabetes are obsolete and that specific genetic etiologies should be sought in four broad clinical situations because of their specific treatment implications. Firstly, diabetes diagnosed before 6 months of age frequently results from mutation of genes that encode Kir6.2 (ATP-sensitive inward rectifier potassium channel) or sulfonylurea receptor 1 subunits of an ATP-sensitive potassium channel, and improved glycemic control can be achieved by treatment with high-dose sulfonylureas rather than insulin. Secondly, patients with stable, mild fasting hyperglycemia detected particularly when they are young could have a glucokinase mutation and might not require specific treatment. Thirdly, individuals with familial, young-onset diabetes that does not fit with either type 1 or type 2 diabetes might have mutations in the transcription factors HNF-1alpha (hepatocyte nuclear factor 1-alpha) or HNF-4alpha, and can be treated with low-dose sulfonylureas. Finally, extrapancreatic features, such as renal disease (caused by mutations in HNF-1beta) or deafness (caused by a mitochondrial m.3243A>G mutation), usually require early treatment with insulin.
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Flechtner I, Vaxillaire M, Cavé H, Scharfmann R, Froguel P, Polak M. Neonatal hyperglycaemia and abnormal development of the pancreas. Best Pract Res Clin Endocrinol Metab 2008; 22:17-40. [PMID: 18279778 DOI: 10.1016/j.beem.2007.08.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Transient and permanent neonatal diabetes mellitus (TNDM and PNDM) are rare conditions occurring in around 1 per 300,000 live births. In TNDM, growth-retarded infants develop diabetes in the first few weeks of life, only to go into remission after a few months with possible relapse to permanent diabetes usually around adolescence or in adulthood. In PNDM, insulin secretory failure occurs in the late fetal or early postnatal period. The very recently elucidated mutations in KCNJ11 and ABCC8 genes, encoding the Kir6.2 and SUR1 subunits of the pancreatic K(ATP) channel involved in regulation of insulin secretion, account for a third to a half of the PNDM cases. Molecular analysis of chromosome 6 anomalies and the KCNJ11 and ABCC8 genes encoding Kir6.2 and SUR1 provides a tool for distinguishing transient from permanent neonatal diabetes mellitus in the neonatal period. Some patients (those with mutations in KCNJ11 and ABCC8) may be transferred from insulin therapy to sulphonylureas.
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MESH Headings
- Chromosome Aberrations
- Chromosomes, Human, Pair 6
- Diabetes Mellitus/drug therapy
- Diabetes Mellitus/epidemiology
- Diabetes Mellitus/genetics
- Diabetes Mellitus/metabolism
- Gene Expression Regulation, Developmental
- Genetic Counseling
- Humans
- Hyperglycemia/drug therapy
- Hyperglycemia/genetics
- Infant
- Infant, Newborn
- Infant, Newborn, Diseases/drug therapy
- Infant, Newborn, Diseases/epidemiology
- Infant, Newborn, Diseases/genetics
- Infant, Newborn, Diseases/metabolism
- Male
- Pancreas/abnormalities
- Pancreas/growth & development
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
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Affiliation(s)
- Isabelle Flechtner
- Clinique des Maladies du Développement, Unité d'Endocrinologie, Diabétologie et Gynécologie Pédiatrique, Hôpital Necker-Enfants Malades, Paris, France
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Abstract
The beta-cell ATP-sensitive potassium channel is a key component of stimulus -secretion coupling in the pancreatic beta-cell. The channel consists of four subunits of the inwardly rectifying potassium channel Kir6.2 and four subunits of the sulfonylurea receptor 1. Loss of function mutations in the KCNJ11 and ABCC8 genes that encode for Kir6.2 and SUR1 can cause over-secretion of insulin and result in hyperinsulinism of infancy, while gain of function mutations in KCNJ11 and ABCC8 have recently been described that result in the opposite phenotype of diabetes.Genetic testing is important for patients with hyperinsulinism or neonatal diabetes, as identification of a K(ATP) channel mutation confirms a diagnosis of their disorder. This genetic information may direct the clinical management; for example, patients with neonatal diabetes may transfer from insulin to sulfonylu-reas with an improvement in glycaemic control. The genetic diagnosis can also help to predict the likely course of the disease and may allow accurate counselling in terms of recurrence risk for these families.This chapter focuses on the methodology used for the analysis of the KCNJ11 gene by direct sequencing. The same principles can be employed for ABCC8 analysis although the polymerase chain reaction (PCR) primers will differ. Details on DNA extraction from peripheral blood leukocytes, amplification of the KCNJ11 gene by the PCR, sequencing, and mutation detection are provided.
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MESH Headings
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/physiopathology
- Diabetes Mellitus, Type 1/therapy
- Humans
- Infant, Newborn
- Infant, Newborn, Diseases/genetics
- Infant, Newborn, Diseases/physiopathology
- Infant, Newborn, Diseases/therapy
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Abstract
Permanent neonatal diabetes mellitus (PNDM) is characterized by the onset of diabetes within the first six months of life and insulin dependence life long. It has been recently discovered that mutation in KCNJ11 gene encoding Kir6.2, the pore forming subunit of ATP sensitive potassium channel (K ATP) is the most common cause and such patients may respond better to oral sulphonylurea drugs than insulin. Here is a rare case of permanent neonatal diabetes due to R20IC mutation in KCNJ11 gene.
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van de Bunt M, Gloyn AL. Monogenic disorders of the pancreatic β-cell: personalizing treatment for rare forms of diabetes and hypoglycemia. Per Med 2007; 4:247-259. [DOI: 10.2217/17410541.4.3.247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Over the past 10–20 years, our understanding of the genetic etiology of monogenic disorders of the pancreatic β-cell has greatly improved. This has enabled clinicians to provide patients with more accurate information regarding prognosis and inheritance and has influenced treatment. Maturity-onset diabetes of the young and neonatal diabetes are two such examples. Patients with maturity-onset diabetes of the young due to glucokinase mutations can usually be managed by diet alone, while those affected by HNF-1α and HNF-4α mutations respond well to low doses of sulfonylureas. The identification of mutations in the ATP-dependent potassium channel genes KCNJ11 and ABCC8 as the most common cause of permanent neonatal diabetes has improved treatment regimes for affected children. In addition to enabling patients to stop insulin injections, their glycemic control has also improved. These advances show the importance of unravelling the genetics of a disease to achieve the best individualized treatment for the patients affected.
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Affiliation(s)
- Martijn van de Bunt
- Oxford University, Diabetes Research Laboratories, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Old Road, Headington, Oxford, OX3 7LJ, UK
| | - Anna L Gloyn
- Oxford University, Diabetes Research Laboratories, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Old Road, Headington, Oxford, OX3 7LJ, UK
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Edghill EL, Gloyn AL, Goriely A, Harries LW, Flanagan SE, Rankin J, Hattersley AT, Ellard S. Origin of de novo KCNJ11 mutations and risk of neonatal diabetes for subsequent siblings. J Clin Endocrinol Metab 2007; 92:1773-7. [PMID: 17327377 PMCID: PMC7611879 DOI: 10.1210/jc.2006-2817] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Activating mutations in the KCNJ11 gene, which encodes the Kir6.2 subunit of the pancreatic beta-cell K(ATP) channel, result in permanent and transient neonatal diabetes. The majority of KCNJ11 mutations are spontaneous, but the parental origin of these mutations is not known. OBJECTIVE Our objective was to determine the parental origin of de novo KCNJ11 mutations and investigate the possibility of mosaicism in transmitting parents. DESIGN We identified 68 index cases with a KCNJ11 mutation where neither parent was known to be affected. DNA was available from both parents of 41 probands. The parental origin of the mutation was determined in 18 families by examination of pedigrees, microsatellite analysis, or allele-specific PCR. RESULTS A nonsignificant excess of paternally derived mutations was found with 13 of 18 (72%) shown to have arisen on the paternal allele. There was no evidence to suggest an association with increased age at conception. In two families, there were half-siblings with permanent neonatal diabetes born to an unaffected father, suggesting germline mosaicism that was confirmed by the presence of the R201C mutation in one father's semen. Somatic mosaicism was detected in one unaffected mother, and this mutation will also be present in her germ cells. CONCLUSION De novo KCNJ11 mutations can arise either during gametogenesis or embryogenesis. The possibility of germline mosaicism means that future siblings are at increased risk of neonatal diabetes, and we recommend that molecular genetic testing is routinely offered at birth for subsequent siblings of children with de novo KCNJ11 mutations.
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Affiliation(s)
- Emma L Edghill
- Department of Molecular Genetics, Royal Devon and Exeter National Health Service Foundation Trust, Barrack Road, Exeter, United Kingdom
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Flechtner I, de Lonlay P, Polak M. Diabetes and hypoglycaemia in young children and mutations in the Kir6.2 subunit of the potassium channel: therapeutic consequences. DIABETES & METABOLISM 2007; 32:569-80. [PMID: 17296510 DOI: 10.1016/s1262-3636(07)70311-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Accepted: 10/09/2006] [Indexed: 02/05/2023]
Abstract
ATP-sensitive potassium channels (K(ATP)) couple cell metabolism to electrical activity by regulating potassium movement across the membrane. These channels are octameric complex with two kind of subunits: four regulatory sulfonylurea receptor (SUR) embracing four poreforming inwardly rectifying potassium channel (Kir). Several isoforms exist for each type of subunits: SUR1 is found in the pancreatic beta-cell and neurons, whereas SUR2A is in heart cells and SUR2B in smooth muscle; Kir6.2 is in the majority of tissues as pancreatic beta-cells, brain, heart and skeletal muscle, and Kir6.1 can be found in smooth vascular muscle and astrocytes. The K(ATP) channels play multiple physiological roles in the glucose metabolism regulation, especially in beta-cells where it regulates insulin secretion, in response to an increase in ATP concentration. They also seem to be critical metabolic sensors in protection against metabolic stress as hypo or hyperglycemia, hypoxia, ischemia. Persistent hyperinsulinemic hypoglycaemia (HI) of infancy is a heterogeneous disorder which may be divided into two histopathological forms (diffuse and focal lesions). Different inactivating mutations have been implicated in both forms: the permanent inactivation of the K(ATP) channels provokes inappropriate insulin secretion, despite low ATP. Diazoxide, used efficiently in certain cases of HI, opens the K(ATP) channels and therefore overpass the mutation effect on the insulin secretion. Conversely, several studies reported sequencing of KCNJ11, coding for Kir6.2, in patients with permanent neonatal diabetes mellitus and found different mutations in 30 to 50% of the cases. More than 28 heterozygous activating mutations have now been identified, the most frequent mutation being in the aminoacid R201. These mutations result in reduced ATP-sensitivity of the K(ATP) channels compared with the wild-types and the level of channel block is responsible for different clinical features: the "mild" form confers isolated permanent neonatal diabetes whereas the severe form combines diabetes and neurological symptoms such as epilepsy, deve-lopmental delay, muscle weakness and mild dimorphic features. Sulfonylureas close K(ATP) channels by binding with high affinity to SUR suggesting they could replace insulin in these patients. Subsequently, more than 50 patients have been reported as successfully and safely switched from subcutaneous insulin injections to oral sulfonylurea therapy, with an improvement in their glycated hemoglobin. We therefore designed a protocol to transfer and evaluate children who have insulin treated neonatal diabetes due to KCNJ11 mutation, from insulin to sulfonylurea. The transfer from insulin injections to oral glibenclamide therapy seems highly effective for most patients and safe. This shows how the molecular understan-ding of some monogenic form of diabetes may lead to an unexpected change of the treatment in children. This is a spectacular example by which a pharmacogenomic approach improves the quality of life of our young diabetic patients in a tremendous way.
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Affiliation(s)
- I Flechtner
- Clinique des Maladies du Développement, Unité d'Endocrinologie, Diabétologie et Gynécologie Pédiatrique, Hôpital Necker-Enfants malades, 149, rue de Sèvres, Paris, France.
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Pearson ER, Boj SF, Steele AM, Barrett T, Stals K, Shield JP, Ellard S, Ferrer J, Hattersley AT. Macrosomia and hyperinsulinaemic hypoglycaemia in patients with heterozygous mutations in the HNF4A gene. PLoS Med 2007; 4:e118. [PMID: 17407387 PMCID: PMC1845156 DOI: 10.1371/journal.pmed.0040118] [Citation(s) in RCA: 267] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Accepted: 02/01/2007] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Macrosomia is associated with considerable neonatal and maternal morbidity. Factors that predict macrosomia are poorly understood. The increased rate of macrosomia in the offspring of pregnant women with diabetes and in congenital hyperinsulinaemia is mediated by increased foetal insulin secretion. We assessed the in utero and neonatal role of two key regulators of pancreatic insulin secretion by studying birthweight and the incidence of neonatal hypoglycaemia in patients with heterozygous mutations in the maturity-onset diabetes of the young (MODY) genes HNF4A (encoding HNF-4alpha) and HNF1A/TCF1 (encoding HNF-1alpha), and the effect of pancreatic deletion of Hnf4a on foetal and neonatal insulin secretion in mice. METHODS AND FINDINGS We examined birthweight and hypoglycaemia in 108 patients from families with diabetes due to HNF4A mutations, and 134 patients from families with HNF1A mutations. Birthweight was increased by a median of 790 g in HNF4A-mutation carriers compared to non-mutation family members (p < 0.001); 56% (30/54) of HNF4A-mutation carriers were macrosomic compared with 13% (7/54) of non-mutation family members (p < 0.001). Transient hypoglycaemia was reported in 8/54 infants with heterozygous HNF4A mutations, but was reported in none of 54 non-mutation carriers (p = 0.003). There was documented hyperinsulinaemia in three cases. Birthweight and prevalence of neonatal hypoglycaemia were not increased in HNF1A-mutation carriers. Mice with pancreatic beta-cell deletion of Hnf4a had hyperinsulinaemia in utero and hyperinsulinaemic hypoglycaemia at birth. CONCLUSIONS HNF4A mutations are associated with a considerable increase in birthweight and macrosomia, and are a novel cause of neonatal hypoglycaemia. This study establishes a key role for HNF4A in determining foetal birthweight, and uncovers an unanticipated feature of the natural history of HNF4A-deficient diabetes, with hyperinsulinaemia at birth evolving to decreased insulin secretion and diabetes later in life.
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Affiliation(s)
- Ewan R Pearson
- Peninsula Medical School, Exeter, United Kingdom
- Division of Medicine and Therapeutics, Ninewells Hospital and Medical School, University of Dundee, Dundee, United Kingdom
| | - Sylvia F Boj
- Department of Endocrinology, Hospital Clinic de Barcelona, Barcelona, Spain
- Genomic Programming of Beta Cells Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | | | | | - Karen Stals
- Peninsula Medical School, Exeter, United Kingdom
| | - Julian P Shield
- Bristol Royal Hospital for Children, Bristol, United Kingdom
- University of Bristol, Bristol, United Kingdom
| | - Sian Ellard
- Peninsula Medical School, Exeter, United Kingdom
| | - Jorge Ferrer
- Department of Endocrinology, Hospital Clinic de Barcelona, Barcelona, Spain
- Genomic Programming of Beta Cells Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Andrew T Hattersley
- Peninsula Medical School, Exeter, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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