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Speck SL, Wei X, Semenkovich CF. Depalmitoylation and cell physiology: APT1 as a mediator of metabolic signals. Am J Physiol Cell Physiol 2024; 326:C1034-C1041. [PMID: 38344800 PMCID: PMC11193526 DOI: 10.1152/ajpcell.00542.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 03/13/2024]
Abstract
More than half of the global population is obese or overweight, especially in Western countries, and this excess adiposity disrupts normal physiology to cause chronic diseases. Diabetes, an adiposity-associated epidemic disease, affects >500 million people, and cases are projected to exceed 1 billion before 2050. Lipid excess can impact physiology through the posttranslational modification of proteins, including the reversible process of S-palmitoylation. Dynamic palmitoylation cycling requires the S-acylation of proteins by acyltransferases and the depalmitoylation of these proteins mediated in part by acyl-protein thioesterases (APTs) such as APT1. Emerging evidence points to tissue-specific roles for the depalmitoylase APT1 in maintaining homeostasis in the vasculature, pancreatic islets, and liver. These recent findings raise the possibility that APT1 substrates can be therapeutically targeted to treat the complications of metabolic diseases.
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Affiliation(s)
- Sarah L Speck
- Division of Endocrinology, Metabolism and Lipid Research, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Xiaochao Wei
- Division of Endocrinology, Metabolism and Lipid Research, Washington University in St. Louis, St. Louis, Missouri, United States
| | - Clay F Semenkovich
- Division of Endocrinology, Metabolism and Lipid Research, Washington University in St. Louis, St. Louis, Missouri, United States
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Treatment of HMG-CoA Lyase Deficiency-Longitudinal Data on Clinical and Nutritional Management of 10 Australian Cases. Nutrients 2023; 15:nu15030531. [PMID: 36771238 PMCID: PMC9920477 DOI: 10.3390/nu15030531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 01/09/2023] [Accepted: 01/11/2023] [Indexed: 01/20/2023] Open
Abstract
3-Hydroxy-3-Methylglutaryl-CoA Lyase (HMGCL) deficiency can be a very severe disorder that typically presents with acute metabolic decompensation with features of hypoketotic hypoglycemia, hyperammonemia, and metabolic acidosis. A retrospective chart and literature review of Australian patients over their lifespan, incorporating acute and long-term dietary management, was performed. Data from 10 patients contributed to this study. The index case of this disorder was lost to follow-up, but there is 100% survival in the remainder of the cases despite several having experienced life-threatening episodes. In the acute setting, five of nine patients have used 900 mg/kg/day of sodium D,L 3-hydroxybutyrate in combination with intravenous dextrose-containing fluids (delivering glucose above estimated basal utilization requirements). All patients have been on long-term protein restriction, and those diagnosed more recently have had additional fat restriction. Most patients take L-carnitine. Three children and none of the adults take nocturnal uncooked cornstarch. Of the cohort, there were two patients that presented atypically-one with fulminant liver failure and the other with isolated developmental delay. Dietary management in patients with HMGCL deficiency is well tolerated, and rapid institution of acute supportive metabolic treatment is imperative to optimizing survival and improve outcomes in this disorder.
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Holdar S, Rahbeeni Z, Ramzan K, Imtiaz F. Hepatic Manifestations of 3-Hydroxy-3-Methylglutaryl-Coenzyme-A Lyase Deficiency in Saudi Patients: Experience of a Tertiary Care Center. J Pediatr Genet 2020; 10:105-110. [PMID: 33996180 DOI: 10.1055/s-0040-1714698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 06/11/2020] [Indexed: 10/23/2022]
Abstract
3-Hydroxy-3-methylglutaryl-coenzyme-A lyase (HMGCL) deficiency, a rare autosomal recessive disorder, is caused by a homozygous or compound heterozygous mutation in the HMGCL gene (chromosome 1p36.11). HMGCL catalyzes the final step of leucine degradation and plays a key role in ketone body formation. Several studies have reported general hepatic findings (e.g., hepatomegaly) in patients with HMGCL deficiency, but currently, there are no available data regarding the incidence and epidemiology of liver involvement. The main objective of our study was to investigate the overall clinical manifestations, laboratory findings, genotype, and presence of hepatic involvement in Saudi patients with HMGCL deficiency. A retrospective chart review of patients with HMGCL deficiency including those with a documented hepatic manifestation was performed at the King Faisal Specialist Hospital & Research Centre in Riyadh, Saudi Arabia. We evaluated 50 cases of HMGCL deficiency. Hepatic findings were found in 17 patients at the time of diagnosis. The mean age of hepatic presentation was 135 days, and the median age was 56 days (range: 2-315 days). Hepatomegaly was found in 65%, abnormal biochemical profile in 47%, and an abnormal imaging in 53% of patients. The most frequent mutation in this cohort was the p.Arg41Gln founder mutation (59%). In comparison to data from the current literature, HMGCL deficiency can be considered as a diagnostic metabolite for hepatic manifestations and requires appropriate evaluation, including molecular genetic analysis.
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Affiliation(s)
- Sinan Holdar
- Division of Pediatric Gastroenterology, Department of Pediatrics, Royal Commission Hospital, Jubail, Saudi Arabia
| | - Zuhair Rahbeeni
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Khushnooda Ramzan
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Faiqa Imtiaz
- Department of Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
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4
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Grünert SC, Sass JO. 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency: one disease - many faces. Orphanet J Rare Dis 2020; 15:48. [PMID: 32059735 PMCID: PMC7023732 DOI: 10.1186/s13023-020-1319-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/28/2020] [Indexed: 11/23/2022] Open
Abstract
Background 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMGCLD) is an autosomal recessive disorder of ketogenesis and leucine degradation due to mutations in HMGCL. Method We performed a systematic literature search to identify all published cases. Two hundred eleven patients of whom relevant clinical data were available were included in this analysis. Clinical course, biochemical findings and mutation data are highlighted and discussed. An overview on all published HMGCL variants is provided. Results More than 95% of patients presented with acute metabolic decompensation. Most patients manifested within the first year of life, 42.4% already neonatally. Very few individuals remained asymptomatic. The neurologic long-term outcome was favorable with 62.6% of patients showing normal development. Conclusion This comprehensive data analysis provides a systematic overview on all published cases with HMGCLD including a list of all known HMGCL mutations.
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Affiliation(s)
- Sarah C Grünert
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, Mathildenstr. 1, 79106, Freiburg, Germany.
| | - Jörn Oliver Sass
- Research Group Inborn Errors of Metabolism, Department of Natural Sciences & Institute for Functional Gene Analytics (IFGA), Bonn-Rhein-Sieg University of Applied Sciences, von-Liebig-Str. 20, 53359, Rheinbach, Germany.
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5
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Vargas CR, Ribas GS, da Silva JM, Sitta A, Deon M, de Moura Coelho D, Wajner M. Selective Screening of Fatty Acids Oxidation Defects and Organic Acidemias by Liquid Chromatography/tandem Mass Spectrometry Acylcarnitine Analysis in Brazilian Patients. Arch Med Res 2018; 49:205-212. [PMID: 30119976 DOI: 10.1016/j.arcmed.2018.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/08/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Inborn errors of metabolism (IEM) are diseases which can lead to accumulation of toxic metabolites in the organism. AIM OF THE STUDY To investigate, by selective screening, mitochondrial fatty acid oxidation defects (FAOD) and organic acidemias in Brazilian individuals with clinical suspicion of IEM. METHODS A total of 7,268 individuals, from different regions of Brazil, had whole blood samples impregnated on filter paper which were submitted to the acylcarnitines analysis by liquid chromatography/tandem mass spectrometry (LC/MS/MS) at the Medical Genetics Service of Hospital de Clínicas de Porto Alegre, Brazil, during July 2008-July 2016. RESULTS Our results showed that 68 patients (0.93%) were diagnosed with FAOD (19 cases) and organic acidemias (49 cases). The most prevalent FAOD was multiple acyl CoA dehydrogenase deficiency (MADD), whereas glutaric type I and 3-OH-3-methylglutaric acidemias were the most frequent disorders of organic acid metabolism. Neurologic symptoms and metabolic acidosis were the most common clinical and laboratory features, whereas the average age of the patients at diagnosis was 2.3 years. CONCLUSIONS Results demonstrated a high incidence of glutaric acidemia type I and 3-OH-3- methylglutaric acidemia in Brazil and an unexpectedly low incidence of FAOD, particularly medium-chain acyl-CoA dehydrogenase deficiency (MCADD).
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Affiliation(s)
- Carmen Regla Vargas
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil; Faculdade de Farmácia, UFRGS, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Biológicas, Bioquímica, Faculdade de Farmácia, UFRGS, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, UFRGS, Porto Alegre, RS, Brazil.
| | - Graziela Schmitt Ribas
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Janine Machado da Silva
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil; Faculdade de Farmácia, UFRGS, Porto Alegre, RS, Brazil
| | - Angela Sitta
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | - Marion Deon
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil
| | | | - Moacir Wajner
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil; Programa de Pós-Graduação em Ciências Biológicas, Bioquímica, Faculdade de Farmácia, UFRGS, Porto Alegre, RS, Brazil
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6
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Postmortem genetic analysis of sudden unexpected death in infancy: neonatal genetic screening may enable the prevention of sudden infant death. J Hum Genet 2017; 62:989-995. [DOI: 10.1038/jhg.2017.79] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/27/2017] [Accepted: 06/27/2017] [Indexed: 11/08/2022]
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Grünert SC, Schlatter SM, Schmitt RN, Gemperle-Britschgi C, Mrázová L, Balcı MC, Bischof F, Çoker M, Das AM, Demirkol M, de Vries M, Gökçay G, Häberle J, Uçar SK, Lotz-Havla AS, Lücke T, Roland D, Rutsch F, Santer R, Schlune A, Staufner C, Schwab KO, Mitchell GA, Sass JO. 3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency: Clinical presentation and outcome in a series of 37 patients. Mol Genet Metab 2017; 121:206-215. [PMID: 28583327 DOI: 10.1016/j.ymgme.2017.05.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 05/20/2017] [Indexed: 11/28/2022]
Abstract
3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (HMGCLD) is a rare inborn error of ketone body synthesis and leucine degradation, caused by mutations in the HMGCL gene. In order to obtain a comprehensive view on this disease, we have collected clinical and biochemical data as well as information on HMGCL mutations of 37 patients (35 families) from metabolic centers in Belgium, Germany, The Netherlands, Switzerland, and Turkey. All patients were symptomatic at some stage with 94% presenting with an acute metabolic decompensation. In 50% of the patients, the disorder manifested neonatally, mostly within the first days of life. Only 8% of patients presented after one year of age. Six patients died prior to data collection. Long-term neurological complications were common. Half of the patients had a normal cognitive development while the remainder showed psychomotor deficits. We identified seven novel HMGCL mutations. In agreement with previous reports, no clear genotype-phenotype correlation could be found. This is the largest cohort of HMGCLD patients reported so far, demonstrating that HMGCLD is a potentially life-threatening disease with variable clinical outcome. Our findings suggest that the clinical course of HMGCLD cannot be predicted accurately from HMGCL genotype. The overall outcome in HMGCLD appears limited, thus rendering early diagnosis and strict avoidance of metabolic crises important.
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Affiliation(s)
- Sarah Catharina Grünert
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Sonja Marina Schlatter
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Robert Niklas Schmitt
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Corinne Gemperle-Britschgi
- Division of Clinical Chemistry & Biochemistry and Children's Research Center, University Children's Hospital, Zürich, Switzerland
| | - Lenka Mrázová
- Institute of Inherited Metabolic Disorders, Charles University in Prague - 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Mehmet Cihan Balcı
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Medical Faculty, Istanbul, Turkey
| | - Felix Bischof
- Department of Neurology, University of Tübingen, Germany
| | - Mahmut Çoker
- Division of Metabolism and Nutrition, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Anibh M Das
- Department of Pediatrics, Hannover Medical School, Hannover, Germany
| | - Mübeccel Demirkol
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Medical Faculty, Istanbul, Turkey
| | - Maaike de Vries
- Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gülden Gökçay
- Division of Pediatric Nutrition and Metabolism, Department of Pediatrics, Istanbul Medical Faculty, Istanbul, Turkey
| | - Johannes Häberle
- Division of Metabolism and Children's Research Center, University Children's Hospital, Zürich, Switzerland
| | - Sema Kalkan Uçar
- Division of Metabolism and Nutrition, Department of Pediatrics, Faculty of Medicine, Ege University, Izmir, Turkey
| | - Amelie Sophia Lotz-Havla
- Department of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, Ludwig-Maximilians University, Munich, Germany
| | - Thomas Lücke
- Department of Neuropediatrics, University Children's Hospital, Ruhr-University Bochum, Bochum, Germany
| | - Dominique Roland
- Inborn Errors of Metabolism Unit, Institute of Pathology and Genetics, Charleroi, Gosselies, Belgium
| | - Frank Rutsch
- Department of General Pediatrics, Münster University Children's Hospital, Münster, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andrea Schlune
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University, Düsseldorf, Germany
| | - Christian Staufner
- Department of General Pediatrics, Division of Neuropediatrics and Pediatric Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Karl Otfried Schwab
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Grant A Mitchell
- Centre de Recherche and Département de Pédiatrie, CHU Sainte-Justine, Université de Montréal, Montréal, Québec, Canada; Département de Biochimie, Université de Montréal, Montréal, Québec, Canada
| | - Jörn Oliver Sass
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany; Division of Clinical Chemistry & Biochemistry and Children's Research Center, University Children's Hospital, Zürich, Switzerland; Bioanalytics & Biochemistry, Department of Natural Sciences, University of Applied Sciences, Rheinbach, Germany.
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8
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Roland D, Jissendi-Tchofo P, Briand G, Vamecq J, Fontaine M, Ultré V, Acquaviva-Bourdain C, Mention K, Dobbelaere D. Coupled brain and urine spectroscopy - in vivo metabolomic characterization of HMG-CoA lyase deficiency in 5 patients. Mol Genet Metab 2017; 121:111-118. [PMID: 28396157 DOI: 10.1016/j.ymgme.2017.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/24/2017] [Accepted: 03/24/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND 3-Hydroxy-3-Methylglutaryl-Coenzyme A (HMG-CoA) lyase deficiency is a rare inborn error of leucine metabolism and ketogenesis. Despite recurrent hypoglycemia and metabolic decompensations, most patients have a good clinical and neurological outcome contrasting with abnormal brain magnetic resonance imaging (MRI) signals and consistent abnormal brain proton magnetic resonance spectroscopy (1H-MRS) metabolite peaks. Identifying these metabolites could provide surrogate markers of the disease and improve understanding of MRI-clinical discrepancy and follow-up of affected patients. METHODS Urine samples, brain MRI and 1H-MRS in 5 patients with HMG-CoA lyase deficiency (4 boys and 1 girl aged from 25days to 10years) were, for each patient, obtained on the same day. Brain and urine spectroscopy were performed at the same pH by studying urine at pH 7.4. Due to pH-induced modifications in chemical shifts and because reference 1H NMR spectra are obtained at pH 2.5, spectroscopy of normal urine added with the suspected metabolite was further performed at this pH to validate the correct identification of compounds. RESULTS Mild to extended abnormal white matter MRI signals were observed in all cases. Brain spectroscopy abnormal peaks at 0.8-1.1ppm, 1.2-1.4ppm and 2.4ppm were also detected by urine spectroscopy at pH 7.4. Taking into account pH-induced changes in chemical shifts, brain abnormal peaks in patients were formally identified to be those of 3-hydroxyisovaleric, 3-methylglutaconic, 3-methylglutaric and 3-hydroxy-3-methylglutaric acids. CONCLUSION 3-Methylglutaric, 3-hydroxyisovaleric and 3-hydroxy-3-methylglutaric acids identified on urine 1H-NMR spectra of 5 patients with HMG-CoA lyase deficiency are responsible for the cerebral spectroscopy signature seen in these patients, validating their local involvement in brain and putative contribution to brain neuropathology.
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Affiliation(s)
- Dominique Roland
- Centre Agréé des Maladies Héréditaires du Métabolisme, Centre de Génétique Humaine, Institute of Pathology and Genetics, Gosselies (Charleroi), Belgium.
| | | | - Gilbert Briand
- Department of Biochemistry and Molecular Biology, Laboratory of Endocrinology, Metabolism-Nutrition, Oncology, Pathology Center, CHRU Lille, France
| | - Joseph Vamecq
- Inserm, Biochemistry and Molecular Biology, HMNO, Center of Biology and Pathology Pierre Marie Degand, CHRU Lille, France
| | - Monique Fontaine
- Biochemistry and Molecular Biology, HMNO, Center of Biology and Pathology Pierre Marie Degand, CHRU Lille, France
| | - Vincent Ultré
- UDSL, Laboratoire de RMN, UFR Pharmacie, CHRU Lille, France
| | - Cécile Acquaviva-Bourdain
- Hereditary Metabolic Diseases Service, East Center for Biology and Pathology, Lyon Civil Hospices 69677 Bron cedex, France
| | - Karine Mention
- Centre de Référence Maladies Héréditaires du Métabolisme de l'Enfant et de l'Adulte, Jeanne de Flandre Hospital, CHRU Lille, and RADEME EA 7364, Faculty of Medicine, University Lille 2, Lille 59037, France
| | - Dries Dobbelaere
- Centre de Référence Maladies Héréditaires du Métabolisme de l'Enfant et de l'Adulte, Jeanne de Flandre Hospital, CHRU Lille, and RADEME EA 7364, Faculty of Medicine, University Lille 2, Lille 59037, France.
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9
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3-HMG Coenzyme A Lyase Deficiency: Macrocephaly and Left Ventricular Noncompaction with a Novel Mutation. Indian J Pediatr 2015; 82:645-8. [PMID: 25708061 DOI: 10.1007/s12098-015-1722-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 02/02/2015] [Indexed: 10/24/2022]
Abstract
3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase deficiency, an inborn error of ketone body synthesis and leucine degradation, is a rare autosomal recessive disease. There are a few reports demonstrating clinical and neuroradiologic findings of this condition. The authors report case of an 8-mo-old infant with HMG-CoA lyase deficiency, who presented with macrocephaly, left ventricular noncompaction, recurrent pulmonary infections, nonketotic hypoglycemia, seizure and metabolic acidosis. There was no significant difference in brain magnetic resonance imaging after leucine-restricted diet and carnitine therapy and neurologic deterioration was not observed. Left ventricular noncompaction is an interesting finding for HMG-CoA lyase deficiency which has not been reported in the literature. The genetic analysis revealed a novel homozygote deletion in exon 3 and 4 in HMGCL gene. HMG-CoA lyase deficiency should be thought in the patients with hypoketotic hypoglycemia, hyperammonemia, elevated liver function tests, noncompaction left ventricle and characteristic white matter changes and in the differential diagnosis of macrocephaly.
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10
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Puisac B, Teresa-Rodrigo ME, Arnedo M, Gil-Rodríguez MC, Pérez-Cerdá C, Ribes A, Pié A, Bueno G, Gómez-Puertas P, Pié J. Analysis of aberrant splicing and nonsense-mediated decay of the stop codon mutations c.109G>T and c.504_505delCT in 7 patients with HMG-CoA lyase deficiency. Mol Genet Metab 2013; 108:232-40. [PMID: 23465862 DOI: 10.1016/j.ymgme.2013.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 01/25/2013] [Indexed: 12/13/2022]
Abstract
Eukaryotic cells can be protected against mutations that generate stop codons by nonsense-mediated mRNA decay (NMD) and/or nonsense-associated altered splicing (NAS). However, the processes are only partially understood and do not always occur. In this work, we study these phenomena in the stop codon mutations c.109G>T (p.Glu37*) and c.504_505delCT; the second and third most frequent mutations in HMG-CoA lyase deficiency (MIM #246450). The deficiency affects the synthesis of ketone bodies and produces severe disorders during early childhood. We used a minigene approach, real-time quantitative PCR and the inhibition of NMD by puromycin treatment, to study the effect of stop codons on splicing (NAS) and NMD in seven patients. Surprisingly, none of the stop codons studied appears to be the direct cause of aberrant splicing. In the mutation c.109G>T, the splicing is due to the base change G>T at position 109, which is critical and cannot be explained by disruption of exonic splicing enhancer (ESE) elements, by the appearance of exonic splicing silencer (ESS) elements which were predicted by bioinformatic tools or by the stop codons. Moreover, the mutation c.504_505delCT produces two mRNA transcripts both with stop codons that generate simultaneous NMD phenomena. The effects of the mutations studied on splicing seemed to be similar in all the patients. Furthermore, we report a Spanish patient with 3-hydroxy-3-methylglutaric aciduria and a novel missense mutation: c.825C>G (p.Asn275Lys).
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Affiliation(s)
- Beatriz Puisac
- Unit of Clinical Genetics and Functional Genomics, Department of Pharmacology-Physiology, School of Medicine, University of Zaragoza, E-50009 Zaragoza, Spain
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11
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Reimão S, Morgado C, Almeida IT, Silva M, Corte Real H, Campos J. 3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency: initial presentation in a young adult. J Inherit Metab Dis 2009; 32 Suppl 1:S49-52. [PMID: 19242819 DOI: 10.1007/s10545-009-1048-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Revised: 11/20/2008] [Accepted: 01/04/2009] [Indexed: 10/21/2022]
Abstract
3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase deficiency is a rare inborn error affecting leucine catabolism and ketogenesis, usually presenting in the neonatal period. Late forms of the disease have been detected in infancy and childhood, but not in adults. We report a case of HMG-CoA lyase deficiency with initial presentation in a 29-year-old adult with no prior history of the disease, which to our knowledge is the first case described with presentation at this age.
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Affiliation(s)
- S Reimão
- Department of Neurological Imaging, Sta. Maria Hospital, University of Lisbon, Lisbon, Portugal.
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12
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[Late onset 3-HMG-CoA lyase deficiency: a rare but treatable disorder]. Arch Pediatr 2009; 17:10-3. [PMID: 19932602 DOI: 10.1016/j.arcped.2009.09.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 02/03/2009] [Accepted: 09/30/2009] [Indexed: 11/22/2022]
Abstract
3-Hydroxy-3-methylglutaric aciduria is a rare autosomal recessive genetic disorder due to a deficiency of the 3-hydroxy-3-methylglutarylCoA lyase (HMG-CoA lyase), a mitochondrial enzyme involved in ketogenesis and in the final step of l-leucine catabolism. HMG-CoA lyase deficiency can lead, in particular circumstances, such as fever, prolonged fasting or digestive disorders, to brutal and severe hypoglycemia with metabolic acidosis and sometimes fatal coma. We report on a new case of 3-hydroxy-3-methylglutaric aciduria particular by its late onset in a 3-year-old patient. Molecular investigation identified two new sequence modifications in the HMGCL gene: c.494G>A (p.Arg165Gln) and c.820G>A (p.Gly274Arg). We remind about this case report that the therapeutical is mainly preventive and allows a very good prognosis for this disease. Long-term treatment consists in limited fasting time, continuous low protein diet and l-carnitine supplementation. Preventive measures are essential: prevention of fasting and emergency treatment during intercurrent infections.
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Selective screening for organic acidemias by urine organic acid GC–MS analysis in Brazil: Fifteen-year experience. Clin Chim Acta 2009; 400:77-81. [DOI: 10.1016/j.cca.2008.10.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 09/15/2008] [Accepted: 10/11/2008] [Indexed: 11/18/2022]
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Vargas CR, Sitta A, Schmitt G, Ferreira GC, Cardoso ML, Coelho D, Gibson KM, Wajner M. Incidence of 3-hydroxy-3-methylglutaryl-coenzyme A lyase (HL) deficiency in Brazil, South America. J Inherit Metab Dis 2008; 31 Suppl 3:511-5. [PMID: 18080783 DOI: 10.1007/s10545-007-0756-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 11/05/2007] [Accepted: 11/12/2007] [Indexed: 10/22/2022]
Abstract
3-Hydroxy-3-methylglutaryl-CoA lyase (HL) deficiency (3-hydroxy-3-methylglutaric aciduria, 3-HMG) is a rare autosomal recessive inborn error of metabolism involving the final step of leucine degradation. HL is the key enzyme for the production of glucose-sparing ketone bodies for brain. Positive biochemical findings are metabolic acidosis, hyperammonaemia, and hypoketotic hypoglycaemia in the neonatal period or infancy. In the present study we report 15 Brazilian patients with HL deficiency and present their clinical and biochemical findings. Urine from all patients contained large amounts of 3-hydroxy-3-methylglutaric, 3-methylglutaconic, 3-hydroxyisovaleric and 3-methylglutaric acids, and 3-methylcrotonylglycine was also observed in 13 patients. The main features at clinical presentation were hypoglycaemia (12 patients), seizures (10 patients), metabolic acidosis (9 patients), vomiting (6 patients), and hepatomegaly (5 patients). All but two patients were of Portuguese ancestry. HL deficiency comprised 7.3% of total organic acidurias detected in our laboratory during a 13-year time span, indicating a high incidence of this disorder in Brazil. Limited molecular characterization (4/15 patients only) revealed two mutations common for individuals of Portuguese/Spanish (Iberian Peninsula) ancestry (E37X and V168fs(-2)). Our findings increase the number of HL-deficient patients and reinforce the characteristic phenotypic picture of the disease. Effective dietary interventions based on mild protein restriction and avoidance of fasting and possibly alternative C5 ketone body generating therapy for this disorder may provide further impetus and rationale for expanded newborn screening of HL deficiency.
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Affiliation(s)
- C R Vargas
- Medical Genetics Service, HCPA, Porto Alegre, RS, Brazil
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15
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Lin WD, Wang CH, Lai CC, Tsai Y, Wu JY, Chen CP, Tsai FJ. Molecular analysis of Taiwanese patients with 3-hydroxy-3-methylglutaryl CoA lyase deficiency. Clin Chim Acta 2008; 401:33-6. [PMID: 19036343 DOI: 10.1016/j.cca.2008.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Revised: 10/23/2008] [Accepted: 11/03/2008] [Indexed: 10/21/2022]
Abstract
BACKGROUND 3-Hydroxy-3-methylglutaryl CoA lyase deficiency (HL deficiency) is a rare autosomal recessive mitochondrial disease characterized by a deficiency in the enzyme 3-Hydroxy-3-methylglutaryl CoA lyase (HMGCL). Here, we report on novel mutations identified in the HMGCL gene in 2 Taiwanese patients with HL deficiency. METHODS Analysis of organic acids in urine was performed using gas chromatography-mass spectrometry to confirm HL deficiency in the two subjects. The mutations in their HMGCL genes then were determined by direct sequencing. In addition, the effect of a splice site mutation was determined using reverse transcription-polymerase chain reactions (RT-PCR). RESULTS A total of 3 novel mutations in the HMGCL gene were revealed by molecular analysis: one missense mutation (c.494G>T, p.Arg165Gln) and 2 splice site mutations (IVS3+1G>A, IVS6-1G>A). The results of RT-PCR revealed that an IVS3+1G>A mutation leads to skipping of exon3. We also calculated that the incidence of HL deficiency in Taiwan is <1 per 1,000,000 live births. CONCLUSIONS The results of this study suggest that unique HMGCL gene mutations exist in Taiwanese HL deficiency patients. Therefore, HMGCL gene profiling may be useful in genetic counseling for families affected by HL deficiency.
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Affiliation(s)
- Wei-De Lin
- Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
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16
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The fungus Ustilago maydis and humans share disease-related proteins that are not found in Saccharomyces cerevisiae. BMC Genomics 2007; 8:473. [PMID: 18096044 PMCID: PMC2262911 DOI: 10.1186/1471-2164-8-473] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 12/20/2007] [Indexed: 12/23/2022] Open
Abstract
Background The corn smut fungus Ustilago maydis is a well-established model system for molecular phytopathology. In addition, it recently became evident that U. maydis and humans share proteins and cellular processes that are not found in the standard fungal model Saccharomyces cerevisiae. This prompted us to do a comparative analysis of the predicted proteome of U. maydis, S. cerevisiae and humans. Results At a cut off at 20% identity over protein length, all three organisms share 1738 proteins, whereas both fungi share only 541 conserved proteins. Despite the evolutionary distance between U. maydis and humans, 777 proteins were shared. When applying a more stringent criterion (≥ 20% identity with a homologue in one organism over at least 50 amino acids and ≥ 10% less in the other organism), we found 681 proteins for the comparison of U. maydis and humans, whereas the both fungi share only 622 fungal specific proteins. Finally, we found that S. cerevisiae and humans shared 312 proteins. In the U. maydis to H. sapiens homology set 454 proteins are functionally classified and 42 proteins are related to serious human diseases. However, a large portion of 222 proteins are of unknown function. Conclusion The fungus U. maydis has a long history of being a model system for understanding DNA recombination and repair, as well as molecular plant pathology. The identification of functionally un-characterized genes that are conserved in humans and U. maydis opens the door for experimental work, which promises new insight in the cell biology of the mammalian cell.
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Carrasco P, Menao S, López-Viñas E, Santpere G, Clotet J, Sierra AY, Gratacós E, Puisac B, Gómez-Puertas P, Hegardt FG, Pie J, Casals N. C-terminal end and aminoacid Lys48 in HMG-CoA lyase are involved in substrate binding and enzyme activity. Mol Genet Metab 2007; 91:120-7. [PMID: 17459752 DOI: 10.1016/j.ymgme.2007.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 03/16/2007] [Accepted: 03/16/2007] [Indexed: 11/18/2022]
Abstract
3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase adopts a (betaalpha)(8) TIM barrel structure with an additional beta9, alpha11 and alpha12 helices. Location of HMG part of the substrate has been suggested but the binding mode for the CoA moiety remains to be resolved. As mutation F305 fs(-2), which involves the last 21 residues of the protein, and mutation K48N caused 3-hydroxy-3-methylglutaric aciduria in two patients, we examined the role of the C-terminal end and Lys(48) in enzyme activity. Expression studies of various C-terminal-end-deleted and K48N-mutated proteins revealed that residues 311-313 (localized in the loop between alpha11 and alpha12 helices) and Lys(48) are essential for enzyme activity. An in silico docking model locating HMG-CoA on the surface of the enzyme implicates Asn(311) and Lys(313) in substrate binding by establishing multiple polar contacts with phosphate and ribose groups of adenosine, and Lys(48) by contacting the carboxyl group of the panthotenic acid moiety.
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Affiliation(s)
- Patricia Carrasco
- Department of Biochemistry and Molecular Biology, School of Health Sciences, Universitat Internacional de Catalunya, E-08195 Sant Cugat, Barcelona, Spain
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18
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Almeida LS, Vilarinho L, Darmin PS, Rosenberg EH, Martinez-Muñoz C, Jakobs C, Salomons GS. A prevalent pathogenic GAMT mutation (c.59G>C) in Portugal. Mol Genet Metab 2007; 91:1-6. [PMID: 17336114 DOI: 10.1016/j.ymgme.2007.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 01/09/2007] [Accepted: 01/10/2007] [Indexed: 11/17/2022]
Abstract
Guanidinoacetate methyltransferase (GAMT) deficiency (MIM 601240), an autosomal recessive disorder of creatine biosynthesis, presents with mental retardation, extrapyramidal symptoms, autistic-like behavior and epilepsy. Other hallmarks are cerebral creatine deficiency, increased levels of guanidinoacetate in body fluids and mutations in the GAMT gene. Creatine supplementation partially restores cerebral creatine content. Worldwide, 29 patients have been identified and 15 different mutations have been reported in the GAMT gene. Ten out of these 29 patients are of Portuguese origin. Likely, a founder effect and a high carrier rate in Portugal exist, since in 17 out of the 20 Portuguese alleles the c.59G>C; p.Trp20Ser mutation was found. We investigated the carrier rate of the c.59G>C; p.Trp20Ser mutation in different regions of Portugal and confirmed the pathogenic nature of this missense mutation by transient transfections. Anonymous bloodspots (1002) were screened for the presence of the c.59G>C; p.Trp20Ser mutation by SNaPshot (Single Nucleotide Polymorphism Multiplex Kit). Eight carriers of c.59G>C; p.Trp20Ser were detected of which four are derived from the Archipelagos. This suggests that the carrier rate of the c.59G>C; p.Trp20Ser mutation is relatively high in these islands, as well as in other parts of Portugal. It also implies that newborn screening in these regions is warranted for this treatable disorder.
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Affiliation(s)
- L S Almeida
- Department of Clinical Chemistry, Metabolic Unit, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
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Al-Sayed M, Imtiaz F, Alsmadi OA, Rashed MS, Meyer BF. Mutations underlying 3-hydroxy-3-methylglutaryl CoA lyase deficiency in the Saudi population. BMC MEDICAL GENETICS 2006; 7:86. [PMID: 17173698 PMCID: PMC1764877 DOI: 10.1186/1471-2350-7-86] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2006] [Accepted: 12/16/2006] [Indexed: 11/10/2022]
Abstract
BACKGROUND 3-hydroxy-3-methylglutaric aciduria (3HMG, McKusick: 246450) is an autosomal recessive branched chain organic aciduria caused by deficiency of the enzyme 3-Hydroxy-3-Methylglutaryl CoA lyase (HL, HMGCL, EC 4.1.3.4). HL is encoded by HMGCL gene and many mutations have been reported. 3HMG is commonly observed in Saudi Arabia. METHODS We utilized Whole Genome Amplification (WGA), PCR and direct sequencing to identify mutations underlying 3HMG in the Saudi population. Two patients from two unrelated families and thirty-four 3HMG positive dried blood spots (DBS) were included. RESULTS We detected the common missense mutation R41Q in 89% of the tested alleles (64 alleles). 2 alleles carried the frame shift mutation F305fs (-2) and the last two alleles had a novel splice site donor IVS6+1G>A mutation which was confirmed by its absence in more than 100 chromosomes from the normal population. All mutations were present in a homozygous state, reflecting extensive consanguinity. The high frequency of R41Q is consistent with a founder effect. Together the three mutations described account for >94% of the pathogenic mutations underlying 3HMG in Saudi Arabia. CONCLUSION Our study provides the most extensive genotype analysis on 3HMG patients from Saudi Arabia. Our findings have direct implications on rapid molecular diagnosis, prenatal and pre-implantation diagnosis and population based prevention programs directed towards 3HMG.
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Affiliation(s)
- Moeenaldeen Al-Sayed
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
| | - Faiqa Imtiaz
- Arabian Diagnostics Laboratory, King Faisal Specialist Hospital & Research Centre, PO Box 3354, Riyadh 11211, Saudi Arabia
| | - Osama A Alsmadi
- Arabian Diagnostics Laboratory, King Faisal Specialist Hospital & Research Centre, PO Box 3354, Riyadh 11211, Saudi Arabia
| | - Mohammed S Rashed
- Department of Medical Genetics, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia
- National Laboratory for Newborn Screening, King Faisal Specialist Hospital & Research Centre, PO Box 3354, Riyadh 11211, Saudi Arabia
| | - Brian F Meyer
- Arabian Diagnostics Laboratory, King Faisal Specialist Hospital & Research Centre, PO Box 3354, Riyadh 11211, Saudi Arabia
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Mir C, Lopez-Viñas E, Aledo R, Puisac B, Rizzo C, Dionisi-Vici C, Deodato F, Pié J, Gomez-Puertas P, Hegardt FG, Casals N. A single-residue mutation, G203E, causes 3-hydroxy-3-methylglutaric aciduria by occluding the substrate channel in the 3D structural model of HMG-CoA lyase. J Inherit Metab Dis 2006; 29:64-70. [PMID: 16601870 DOI: 10.1007/s10545-006-0138-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Accepted: 06/03/2005] [Indexed: 11/24/2022]
Abstract
3-Hydroxy-3-methylglutaric aciduria is a rare autosomal recessive genetic disorder that affects ketogenesis and leucine metabolism. The disease is caused by mutations in the gene coding for 3-hydroxy-3-methylglutaryl-coenzyme A lyase (HL). To date 26 different mutations have been described. A (betaalpha)(8) TIM barrel structure has been proposed for the protein, and almost all missense mutations identified so far localize in the beta sheets that define the inside cavity. We report an Italian patient who bears homozygously a novel HL mutation, c.608G > A (p. G203E) in beta sheet six. A structural model of the mutated protein suggests that glutamic acid 203 impedes catalysis by blocking the entrance to the inner cavity of the enzyme. Loss of functionality has been confirmed in expression studies in E. coli, which demonstrate that the G203E mutation completely abolishes enzyme activity. Beta sheet six and beta sheet two are the two protein regions that accumulate most missense mutations, indicating their importance in enzyme functionality. A model for the mechanism of enzyme function is proposed.
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Affiliation(s)
- C Mir
- Department of Biochemistry and Molecular Biology, Faculty of Health Sciences, International University of Catalonia, C/ Josep Trueta s/n, E-08190 Sant Cugat del Valles, Barcelona, Spain
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Forouhar F, Hussain M, Farid R, Benach J, Abashidze M, Edstrom WC, Vorobiev SM, Xiao R, Acton TB, Fu Z, Kim JJP, Miziorko HM, Montelione GT, Hunt JF. Crystal structures of two bacterial 3-hydroxy-3-methylglutaryl-CoA lyases suggest a common catalytic mechanism among a family of TIM barrel metalloenzymes cleaving carbon-carbon bonds. J Biol Chem 2005; 281:7533-45. [PMID: 16330546 DOI: 10.1074/jbc.m507996200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase catalyzes the terminal steps in ketone body generation and leucine degradation. Mutations in this enzyme cause a human autosomal recessive disorder called primary metabolic aciduria, which typically kills victims because of an inability to tolerate hypoglycemia. Here we present crystal structures of the HMG-CoA lyases from Bacillus subtilis and Brucella melitensis at 2.7 and 2.3 A resolution, respectively. These enzymes share greater than 45% sequence identity with the human orthologue. Although the enzyme has the anticipated triose-phosphate isomerase (TIM) barrel fold, the catalytic center contains a divalent cation-binding site formed by a cluster of invariant residues that cap the core of the barrel, contrary to the predictions of homology models. Surprisingly, the residues forming this cation-binding site and most of their interaction partners are shared with three other TIM barrel enzymes that catalyze diverse carbon-carbon bond cleavage reactions believed to proceed through enolate intermediates (4-hydroxy-2-ketovalerate aldolase, 2-isopropylmalate synthase, and transcarboxylase 5S). We propose the name "DRE-TIM metallolyases" for this newly identified enzyme family likely to employ a common catalytic reaction mechanism involving an invariant Asp-Arg-Glu (DRE) triplet. The Asp ligates the divalent cation, while the Arg probably stabilizes charge accumulation in the enolate intermediate, and the Glu maintains the precise structural alignment of the Asp and Arg. We propose a detailed model for the catalytic reaction mechanism of HMG-CoA lyase based on the examination of previously reported product complexes of other DRE-TIM metallolyases and induced fit substrate docking studies conducted using the crystal structure of human HMG-CoA lyase (reported in the accompanying paper by Fu, et al. (2006) J. Biol. Chem. 281, 7526-7532). Our model is consistent with extensive mutagenesis results and can guide subsequent studies directed at definitive experimental elucidation of this enzyme's reaction mechanism.
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Affiliation(s)
- Farhad Forouhar
- Department of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, NY 10027, USA
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Puisac B, López-Viñas E, Moreno S, Mir C, Pérez-Cerdá C, Menao S, Lluch D, Pié A, Gómez-Puertas P, Casals N, Ugarte M, Hegardt F, Pié J. Skipping of exon 2 and exons 2 plus 3 of HMG-CoA lyase (HL) gene produces the loss of beta sheets 1 and 2 in the recently proposed (beta-alpha)8 TIM barrel model of HL. Biophys Chem 2005; 115:241-5. [PMID: 15752612 DOI: 10.1016/j.bpc.2004.12.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Revised: 11/25/2004] [Accepted: 12/10/2004] [Indexed: 10/26/2022]
Abstract
HMG-CoA lyase (HL) deficiency is a rare autosomal recessive genetic disorder that affects ketogenesis and leucine catabolism. We report a new Spanish patient who bears the frequent nonsense mutation G109T (Mediterranean mutation). This mutation can produce aberrant splicing with three mRNA variants: one of the expected size, the second with deletion of exon 2, and the third with deletion of exons 2 and 3. Recently our group proposed a 3D model for human HL containing a (beta-alpha)(8) (TIM) barrel structure. We have studied the effect of the deletions of exon 2 and exons 2 plus 3 on the proposed HL model. Exon 2 skipping led to the loss of beta-sheet 1, and the skipping of exons 2 and 3 caused the disappearance of alpha helix 1 and beta-sheets 1 and 2.-
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Affiliation(s)
- Beatriz Puisac
- Department of Pharmacology and Physiology, School of Medicine, University of Zaragoza, C/Domingo Miral s/n, E-50009 Zaragoza, Spain
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