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Bai R, He AL, Guo J, Li Z, Yu X, Zeng J, Mi Y, Wang L, Zhang J, Yang D. Novel pathogenic variant (c.2947C > T) of the carbamoyl phosphate synthetase 1 gene in neonatal-onset deficiency. Front Neurosci 2022; 16:1025572. [PMID: 36340787 PMCID: PMC9634248 DOI: 10.3389/fnins.2022.1025572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/06/2022] [Indexed: 11/13/2022] Open
Abstract
Background Carbamoyl phosphate synthetase 1 deficiency (CPS1D) is a rare autosomal recessive urea cycle disorder characterized by hyperammonaemia. The biochemical measurement of the intermediate metabolites is helpful for CPS1D diagnosis; it however cannot distinguish CPS1D from N-acetylglutamate synthetase deficiency. Therefore, next-generation sequencing (NGS) is often essential for the accurate diagnosis of CPS1D. Methods NGS was performed to identify candidate gene variants of CPS1D in a Asian neonatal patient presented with poor feeding, reduced activity, tachypnea, lethargy, and convulsions. The potential pathogenicity of the identified variants was predicted by various types of bioinformatical analyses, including evolution conservation, domain and 3D structure simulations. Results Compound heterozygosity of CPS1D were identified. One was in exon 24 with a novel heterozygous missense variant c.2947C > T (p.P983S), and another was previously reported in exon 20 with c.2548C > T (p.R850C). Both variants were predicted to be deleterious. Conservation analysis and structural modeling showed that the two substituted amino acids were highly evolutionarily conserved, resulting in potential decreases of the binding pocket stability and the partial loss of enzyme activity. Conclusion In this study, two pathogenic missense variants were identified with NGS, expanding the variants pectrum of the CPS1 gene. The variants and related structural knowledge of CPS enzyme demonstrate the applicability for the accurate diagnosis of CPS1D.
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Affiliation(s)
- Ruimiao Bai
- Department of Neonatology, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - ALing He
- Department of Neonatology, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - Jinzhen Guo
- Department of Neonatology, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - Zhankui Li
- Department of Neonatology, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - Xiping Yu
- Department of Neonatology, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - JunAn Zeng
- Department of Neonatology, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - Yang Mi
- Department of Obstetrics, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - Lin Wang
- Genetics Center, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - Jingjing Zhang
- Medical Imaging Center, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
| | - Dong Yang
- Department of Neonatology, Northwest Women’s and Children’s Hospital, Xi’an, Shaanxi, China
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Hanif S, Sethi SM. Hyperammonemia of unknown cause in a young postpartum woman: a case report. J Med Case Rep 2022; 16:96. [PMID: 35249549 PMCID: PMC8900310 DOI: 10.1186/s13256-022-03304-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 02/01/2022] [Indexed: 11/12/2022] Open
Abstract
Background Hyperammonemia is a medical condition described as increased or elevated serum ammonia levels. High serum levels of ammonia can cause neurotoxicity. Sudden onset severe hyperammonemia may cause severe encephalopathy with brain damage. It can result in cerebral edema, emesis, seizures, hypotonia, and death. We report a young postpartum woman who had a sudden rise in serum ammonia levels after vaginal delivery. Case presentation A 24-year-old, married, postpartum Pakistani woman was admitted to the intensive care unit through the emergency department, with complaints of fever, severe abdominal pain with distension, and altered levels of consciousness. The patient had a medical history of spontaneous vaginal delivery 2 weeks before this hospital admission, after which she gradually developed the above symptoms. However, the patient’s past medical history was unremarkable with no hepatic disease, but her investigations revealed a progressive rise in serum ammonia levels. In the intensive care unit, she developed generalized tonic–clonic seizures. This was followed by a coma, tonsillar herniation, and death. Conclusion Postpartum hyperammonemia is a rare entity. It is a critical illness and must be evaluated for underlying metabolic disorders. Early diagnosis and treatment may result in better outcomes and reduced mortality among postpartum women with hyperammonemia.
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3
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Zhou Y, Eid T, Hassel B, Danbolt NC. Novel aspects of glutamine synthetase in ammonia homeostasis. Neurochem Int 2020; 140:104809. [DOI: 10.1016/j.neuint.2020.104809] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023]
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4
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Phillips MR, Schwartz SP, Smith MM, Leung D, McLean SE, Clement KC. Neonatal ECMO for Cardiopulmonary Failure Due to Carbamoyl Phosphate Synthetase I Deficiency. Am Surg 2020; 88:306-307. [PMID: 32755389 DOI: 10.1177/0003134820940630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Michael R Phillips
- 214495 Department of Surgery, The University of North Carolina, Chapel Hill, NC, USA
| | - Stephanie P Schwartz
- 549964 Department of Pediatrics, The University of North Carolina, Chapel Hill, NC, USA
| | - Melissa M Smith
- 549964 Department of Pediatrics, The University of North Carolina, Chapel Hill, NC, USA
| | - Dennis Leung
- 549964 Department of Pediatrics, The University of North Carolina, Chapel Hill, NC, USA
| | - Sean E McLean
- 214495 Department of Surgery, The University of North Carolina, Chapel Hill, NC, USA
| | - Katherine C Clement
- 549964 Department of Pediatrics, The University of North Carolina, Chapel Hill, NC, USA
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5
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CPS1 T1405N polymorphism, HDL cholesterol, homocysteine and renal function are risk factors of VPA induced hyperammonemia among epilepsy patients. Epilepsy Res 2019; 154:139-143. [PMID: 31151073 DOI: 10.1016/j.eplepsyres.2019.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 05/07/2019] [Accepted: 05/17/2019] [Indexed: 01/15/2023]
Abstract
PURPOSE Valproic acid (VPA) is frequently used in the treatment of epilepsy. The adverse effects of VPA include hyperammonemia (HA) which is characterized by abnormally elevated blood ammonia level. Carbamoyl-Phosphate Synthase 1 (CPS1) is an enzyme catalyzing the initial step of removing ammonia from blood. Studies have demonstrated that the CPS1 polymorphism rs1047891-A allele carriers were susceptible to VPA-induced HA. However, the evidences remained controversial. In this study, we sought to validate the association between rs1047891 and VPA-induced HA by combining the association results from previous studies together. METHODS We first conducted a systematic meta-analysis to determine whether rs1047891 was statistically significant. Then, we further evaluated the pleiotropic effects of rs1047891 using published genome-wide association studies (GWAS) and UKBB results. A conditional analysis was conducted to investigate whether the association between rs1047891 and VPA-induced HA was mediated by cardiovascular or renal disease risk factors or vice versa. RESULTS The allelic, dominant and recessive ORs of rs1047891-A were all significant in our fixed-effect meta-analysis. In GWAS catalog and UKBB data, rs1047891 was associated with basal metabolic rate, adiposity and hematology traits, cardiovascular and renal disease risk factors. We further proved that plasma HDL cholesterol and homocysteine level, in addition to eGFR by serum creatinine, were associated with VPA-induced HA risk independently from rs1047891 polymorphism. CONCLUSION In conclusion, the SNP rs1047891 was associated with VPA-induce HA among epilepsy patients. Meanwhile, plasma HDL cholesterol and homocysteine level had independent effects from it.
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6
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Abstract
The immediate postpartum period is a time of acute vulnerability to mental illness, which presents unique challenges for the psychiatric consultant. Because the postpartum hospital stay is typically brief, the consultant must have a working knowledge of postpartum physiology and the myriad forms of mental illness that may emerge in this vulnerable time, in order to quickly make a diagnosis and formulate a treatment plan. This review aims to characterize the most common reasons for postpartum consultation, review postpartum physiology and psychiatric conditions, and propose an evidence-based, practical approach to treatment. A literature search using the terms "postpartum," "obstetric," "consultation," and "psychiatry" yielded six studies that identified reasons for psychiatric consultation to the obstetrics and gynecology services. These studies informed the structure of the article such that we review the most common reasons for consultation and how to approach each issue. The most common reason for consultation is past psychiatric history, often in the absence of current symptoms. For each clinical situation, including depression, adverse birth events, and psychosis, we present a differential diagnosis, as well as risk factors, clinical signs, and recommended treatment.
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Affiliation(s)
- Eleanor A Anderson
- Patient and Family Services, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, 1st Floor South Pavilion, Philadelphia, PA, 19104, USA,
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7
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Häberle J, Boddaert N, Burlina A, Chakrapani A, Dixon M, Huemer M, Karall D, Martinelli D, Crespo PS, Santer R, Servais A, Valayannopoulos V, Lindner M, Rubio V, Dionisi-Vici C. Suggested guidelines for the diagnosis and management of urea cycle disorders. Orphanet J Rare Dis 2012; 7:32. [PMID: 22642880 PMCID: PMC3488504 DOI: 10.1186/1750-1172-7-32] [Citation(s) in RCA: 357] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 04/06/2012] [Indexed: 12/11/2022] Open
Abstract
Urea cycle disorders (UCDs) are inborn errors of ammonia detoxification/arginine synthesis due to defects affecting the catalysts of the Krebs-Henseleit cycle (five core enzymes, one activating enzyme and one mitochondrial ornithine/citrulline antiporter) with an estimated incidence of 1:8.000. Patients present with hyperammonemia either shortly after birth (~50%) or, later at any age, leading to death or to severe neurological handicap in many survivors. Despite the existence of effective therapy with alternative pathway therapy and liver transplantation, outcomes remain poor. This may be related to underrecognition and delayed diagnosis due to the nonspecific clinical presentation and insufficient awareness of health care professionals because of disease rarity. These guidelines aim at providing a trans-European consensus to: guide practitioners, set standards of care and help awareness campaigns. To achieve these goals, the guidelines were developed using a Delphi methodology, by having professionals on UCDs across seven European countries to gather all the existing evidence, score it according to the SIGN evidence level system and draw a series of statements supported by an associated level of evidence. The guidelines were revised by external specialist consultants, unrelated authorities in the field of UCDs and practicing pediatricians in training. Although the evidence degree did hardly ever exceed level C (evidence from non-analytical studies like case reports and series), it was sufficient to guide practice on both acute and chronic presentations, address diagnosis, management, monitoring, outcomes, and psychosocial and ethical issues. Also, it identified knowledge voids that must be filled by future research. We believe these guidelines will help to: harmonise practice, set common standards and spread good practices with a positive impact on the outcomes of UCD patients.
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Affiliation(s)
- Johannes Häberle
- University Children’s Hospital Zurich and Children’s Research Centre, Zurich, 8032, Switzerland
| | - Nathalie Boddaert
- Radiologie Hopital Necker, Service Radiologie Pediatrique, 149 Rue De Sevres, Paris 15, 75015, France
| | - Alberto Burlina
- Department of Pediatrics, Division of Inborn Metabolic Disease, University Hospital Padua, Via Giustiniani 3, Padova, 35128, Italy
| | - Anupam Chakrapani
- Birmingham Children’s Hospital NHS Foundation Trust, Steelhouse Lane, Birmingham, B4 6NH, United Kingdom
| | - Marjorie Dixon
- Dietetic Department, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, WC1N 3JH, United Kingdom
| | - Martina Huemer
- Kinderabteilung, LKH Bregenz, Carl-Pedenz-Strasse 2, Bregenz, A-6900, Austria
| | - Daniela Karall
- University Children’s Hospital, Medical University Innsbruck, Anichstrasse 35, Innsbruck, 6020, Austria
| | - Diego Martinelli
- Division of Metabolism, Bambino Gesù Children’s Hospital, IRCCS, Piazza S. Onofrio 4, Rome, I-00165, Italy
| | | | - René Santer
- Universitätsklinikum Hamburg Eppendorf, Klinik für Kinder- und Jugendmedizin, Martinistr. 52, Hamburg, 20246, Germany
| | - Aude Servais
- Service de Néphrologie et maladies métaboliques adulte Hôpital Necker 149, rue de Sèvres, Paris, 75015, France
| | - Vassili Valayannopoulos
- Reference Center for Inherited Metabolic Disorders (MaMEA), Hopital Necker-Enfants Malades, 149 Rue de Sevres, Paris, 75015, France
| | - Martin Lindner
- University Children’s Hospital, Im Neuenheimer Feld 430, Heidelberg, 69120, Germany
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas (IBV-CSIC) and Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER), C/ Jaume Roig 11, Valencia, 46010, Spain
| | - Carlo Dionisi-Vici
- Division of Metabolism, Bambino Gesù Children’s Hospital, IRCCS, Piazza S. Onofrio 4, Rome, I-00165, Italy
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8
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Langendonk JG, Roos JCP, Angus L, Williams M, Karstens FPJ, de Klerk JBC, Maritz C, Ben-Omran T, Williamson C, Lachmann RH, Murphy E. A series of pregnancies in women with inherited metabolic disease. J Inherit Metab Dis 2012; 35:419-24. [PMID: 21918856 DOI: 10.1007/s10545-011-9389-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/07/2011] [Accepted: 08/18/2011] [Indexed: 12/17/2022]
Abstract
In this case series we report 12 pregnancies, in women treated at four centres, illustrating some of the issues that may be encountered during pregnancy by women with inherited metabolic disease. We discuss how specific pregnancy, labour and delivery issues for mothers with methylmalonic acidemia, homocystinuria, propionic acidemia, glutaric acidemia type 1, ornithine transcarbamylase (OTC) deficiency and 3-hydroxy-3-methylglutaric(HMG)-CoA lyase deficiency were managed and the outcome for the mother and child in each case. Eight of the 12 pregnancies resulted in the successful delivery of a liveborn infant. Several women experienced decompensation of their condition during pregnancy or the post-partum period. There was one maternal death in a women with 3-hydroxy-3-methylglutaric(HMG)-CoA lyase deficiency. Pre-pregnancy counselling and co-management of high risk medical patients by obstetricians and specialist physicians with an understanding of the relationship between pregnancy and inherited metabolic disease is essential.
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Affiliation(s)
- Janneke G Langendonk
- Centre for Lysosomal and Metabolic diseases, Departments of Internal Medicine and Pediatrics, Erasmus MC, Rotterdam, The Netherlands
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9
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Bates TR, Lewis BD, Burnett JR, So K, Mitchell A, Delriviere L, Jeffrey GP. Late-onset carbamoyl phosphate synthetase 1 deficiency in an adult cured by liver transplantation. Liver Transpl 2011; 17:1481-4. [PMID: 21837743 DOI: 10.1002/lt.22407] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Urea cycle disorders (UCDs) are rare causes of hyperammonemic encephalopathy in adults. Most UCDs present in childhood and, if unrecognized, are rapidly fatal. Affected individuals who survive to adulthood may remain undiagnosed because of clinicians' unawareness of the condition or atypical presentations. We describe the case of a 49-year-old man who initially presented with a stroke and developed hyperammonemic encephalopathy over a period of 8 months. A diagnosis of carbamoyl phosphate synthetase type 1 deficiency was made, and the patient was referred for liver transplantation. One year after liver transplantation, the patient had normal plasma ammonia concentrations and had returned to work.
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Affiliation(s)
- Timothy R Bates
- Department of Internal Medicine, Swan District Hospital, Middle Swan, Western Australia, Australia.
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10
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Häberle J, Shchelochkov OA, Wang J, Katsonis P, Hall L, Reiss S, Eeds A, Willis A, Yadav M, Summar S, Lichtarge O, Rubio V, Wong LJ, Summar M. Molecular defects in human carbamoy phosphate synthetase I: mutational spectrum, diagnostic and protein structure considerations. Hum Mutat 2011; 32:579-89. [PMID: 21120950 DOI: 10.1002/humu.21406] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 10/27/2010] [Indexed: 11/09/2022]
Abstract
Deficiency of carbamoyl phosphate synthetase I (CPSI) results in hyperammonemia ranging from neonatally lethal to environmentally induced adult-onset disease. Over 24 years, analysis of tissue and DNA samples from 205 unrelated individuals diagnosed with CPSI deficiency (CPSID) detected 192 unique CPS1 gene changes, of which 130 are reported here for the first time. Pooled with the already reported mutations, they constitute a total of 222 changes, including 136 missense, 15 nonsense, 50 changes of other types resulting in enzyme truncation, and 21 other changes causing in-frame alterations. Only ∼10% of the mutations recur in unrelated families, predominantly affecting CpG dinucleotides, further complicating the diagnosis because of the "private" nature of such mutations. Missense changes are unevenly distributed along the gene, highlighting the existence of CPSI regions having greater functional importance than other regions. We exploit the crystal structure of the CPSI allosteric domain to rationalize the effects of mutations affecting it. Comparative modeling is used to create a structural model for the remainder of the enzyme. Missense changes are found to directly correlate, respectively, with the one-residue evolutionary importance and inversely correlate with solvent accessibility of the mutated residue. This is the first large-scale report of CPS1 mutations spanning a wide variety of molecular defects highlighting important regions in this protein.
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Affiliation(s)
- Johannes Häberle
- University Children's Hospital Zurich, Division of Metabolism, Zurich, Switzerland.
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11
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Martínez AI, Pérez-Arellano I, Pekkala S, Barcelona B, Cervera J. Genetic, structural and biochemical basis of carbamoyl phosphate synthetase 1 deficiency. Mol Genet Metab 2010; 101:311-23. [PMID: 20800523 DOI: 10.1016/j.ymgme.2010.08.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/02/2010] [Accepted: 08/02/2010] [Indexed: 01/28/2023]
Abstract
Carbamoyl phosphate synthetase 1 (CPS1) plays a paramount role in liver ureagenesis since it catalyzes the first and rate-limiting step of the urea cycle, the major pathway for nitrogen disposal in humans. CPS1 deficiency (CPS1D) is an autosomal recessive inborn error which leads to hyperammonemia due to mutations in the CPS1 gene, or is caused secondarily by lack of its allosteric activator NAG. Proteolytic, immunological and structural data indicate that human CPS1 resembles Escherichia coli CPS in structure, and a 3D model of CPS1 has been presented for elucidating the pathogenic role of missense mutations. Recent availability of CPS1 expression systems also can provide valuable tools for structure-function analysis and pathogenicity-testing of mutations in CPS1. In this paper, we provide a comprehensive compilation of clinical CPS1 mutations, and discuss how structural knowledge of CPS enzymes in combination with in vitro analyses can be a useful tool for diagnosis of CPS1D.
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Affiliation(s)
- Ana Isabel Martínez
- Molecular Recognition Laboratory, Centro de Investigación Príncipe Felipe (CIPF) Valencia, Spain
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12
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Kotani Y, Shiota M, Umemoto M, Tsuritani M, Hoshiai H. Carbamyl phosphate synthetase deficiency and postpartum hyperammonemia. Am J Obstet Gynecol 2010; 203:e10-1. [PMID: 20471629 DOI: 10.1016/j.ajog.2010.03.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 03/01/2010] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
Carbamyl phosphate synthetase (CPS) is an enzyme that converts ammonia to carbamyl phosphate in the urea cycle. CPS deficiency is a genetic disorder that causes hyperammonemia because of enzyme activity deficiency. It is primarily diagnosed in neonates and infants and has a poor prognosis. We report an adult woman with CPS deficiency who developed hyperammonemia postpartum.
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13
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Ono H, Suto T, Kinoshita Y, Sakano T, Furue T, Ohta T. A case of carbamoyl phosphate synthetase 1 deficiency presenting symptoms at one month of age. Brain Dev 2009; 31:779-81. [PMID: 19167850 DOI: 10.1016/j.braindev.2008.12.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 11/28/2008] [Accepted: 12/19/2008] [Indexed: 10/21/2022]
Abstract
Carbamoyl phosphate synthetase 1 deficiency (CPS1D) is an autosomal recessive disorder of the urea cycle which causes hyperammonemia. Two forms of CPS1D are recognized: a lethal neonatal type and a less severe, delayed onset type. Neonatal CPS1D cases often present their symptoms within the first days of life. Delayed onset type were adolescents or adults, and infantile cases were rare. We report a case of CPS1D in a boy who developed symptoms at one month of age. He showed excellent response to treatments including continuous hemodialysis, drugs and a low-protein diet. His development and weight gain were good at the last follow-up at 1 year and three months of age. Molecular assay of the CPS1 gene demonstrated that the patient was heterozygous for c.2407C>G (R803G: maternal) in exon 20 and c.3784C>T (R1262X: paternal) in exon 32. Our clinical experience suggests that CPS1D could be one of the causes of hyperammonemia in early infantile cases.
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Affiliation(s)
- Hiroaki Ono
- Department of Pediatrics, Hiroshima Prefectural Hospital, 1-5-54 Ujina Kanda, Minami-ku, Hiroshima 734-0844, Japan.
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14
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Deignan JL, Cederbaum SD, Grody WW. Contrasting features of urea cycle disorders in human patients and knockout mouse models. Mol Genet Metab 2008; 93:7-14. [PMID: 17933574 PMCID: PMC2692509 DOI: 10.1016/j.ymgme.2007.08.123] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2007] [Revised: 08/19/2007] [Accepted: 08/19/2007] [Indexed: 10/22/2022]
Abstract
The urea cycle exists for the removal of excess nitrogen from the body. Six separate enzymes comprise the urea cycle, and a deficiency in any one of them causes a urea cycle disorder (UCD) in humans. Arginase is the only urea cycle enzyme with an alternate isoform, though no known human disorder currently exists due to a deficiency in the second isoform. While all of the UCDs usually present with hyperammonemia in the first few days to months of life, most disorders are distinguished by a characteristic profile of plasma amino acid alterations that can be utilized for diagnosis. While enzyme assay is possible, an analysis of the underlying mutation is preferable for an accurate diagnosis. Mouse models for each of the urea cycle disorders exist (with the exception of NAGS deficiency), and for almost all of them, their clinical and biochemical phenotypes rather closely resemble the phenotypes seen in human patients. Consequently, all of the current mouse models are highly useful for future research into novel pharmacological and dietary treatments and gene therapy protocols for the management of urea cycle disorders.
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Affiliation(s)
- Joshua L. Deignan
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
- The Mental Retardation Research Center, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Stephen D. Cederbaum
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA
- The Mental Retardation Research Center, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Wayne W. Grody
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, CA
- Department of Human Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA
- The Mental Retardation Research Center, David Geffen School of Medicine at UCLA, Los Angeles, CA
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15
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Abstract
Patients experiencing acute elevations of ammonia present to the ICU with encephalopathy, which may progress quickly to cerebral herniation. Patient survival requires immediate treatment of intracerebral hypertension and the reduction of ammonia levels. When hyperammonemia is not thought to be the result of liver failure, treatment for an occult disorder of metabolism must begin prior to the confirmation of an etiology. This article reviews ammonia metabolism, the effects of ammonia on the brain, the causes of hyperammonemia, and the diagnosis of inborn errors of metabolism in adult patients.
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Affiliation(s)
- Alison S Clay
- Department of Surgery and Medicine, Duke University Medical Center, Box 2945, Durham, NC 27710, USA.
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16
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Eather G, Coman D, Lander C, McGill J. Carbamyl phosphate synthase deficiency: diagnosed during pregnancy in a 41-year-old. J Clin Neurosci 2006; 13:702-6. [PMID: 16860720 DOI: 10.1016/j.jocn.2005.07.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Accepted: 07/13/2005] [Indexed: 11/27/2022]
Abstract
Carbamyl phosphate synthase deficiency (CPS) is a rare urea cycle defect. We present a case of a 41-year-old woman diagnosed with CPS deficiency during pregnancy. She is the oldest CPS-deficient patient, at diagnosis, reported to date and the first to be diagnosed during pregnancy. This case highlights the need for consideration of inborn errors of metabolism in adults presenting with unusual neurological and psychiatric conditions.
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Affiliation(s)
- G Eather
- Department of Neurology, The Royal Brisbane Hospital, Brisbane, Australia
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17
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Summar ML, Barr F, Dawling S, Smith W, Lee B, Singh RH, Rhead WJ, Sniderman King L, Christman BW. Unmasked adult-onset urea cycle disorders in the critical care setting. Crit Care Clin 2006; 21:S1-8. [PMID: 16227111 DOI: 10.1016/j.ccc.2005.05.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Most often, urea cycle disorders have been described as acute onset hyperammonemia in the newborn period; however, there is a growing awareness that urea cycle disorders can present at almost any age, frequently in the critical care setting. This article presents three cases of adult-onset hyperammonemia caused by inherited defects in nitrogen processing in the urea cycle, and reviews the diagnosis, management, and pathophysiology of adult-onset urea cycle disorders. Individuals who have milder molecular urea cycle defects can lead a relatively normal life until a severe environmental stress triggers a hyperammonemic crisis. Comorbid conditions such as physical trauma often delay the diagnosis of the urea cycle defect. Prompt recognition and treatment are essential in determining the outcome of these patients.
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Affiliation(s)
- Marshall L Summar
- Center for Human Genetic Research, Division of Medical Genetics, Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232-0165, USA.
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18
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Singh RH, Rhead WJ, Smith W, Lee B, Sniderman King L, Summar M. Nutritional management of urea cycle disorders. Crit Care Clin 2006; 21:S27-35. [PMID: 16227113 DOI: 10.1016/j.ccc.2005.08.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Nutritional management of patients who have urea cycle disorders is one of the most challenging tasks in clinical nutrition. The degree to which protein intake should be restricted in urea cycle disorders requires complex calculations which depend on many variables such as specific enzyme defect, age-related growth rate, current health status, level of physical activity, amount of free amino acids administered, energy intake, residual urea cycle function, family lifestyle, use of nitrogen-scavenging medications, and the patient's eating behaviors. This paper presents two case histories and a series of recommendations outlining the nutrition management of urea cycle disorders. It also identifies difficulties that arise in the course of treatment, and suggests practical solutions for overcoming them.
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Affiliation(s)
- Rani H Singh
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30032, USA
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19
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Osada H, Seki K. Amino acid changes during successful pregnancy in a case of lysinuric protein insufficiency. Gynecol Obstet Invest 2005; 61:139-41. [PMID: 16374016 DOI: 10.1159/000090410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Accepted: 10/20/2005] [Indexed: 11/19/2022]
Abstract
Lysinuric protein insufficiency (LPI) is a rare autosomal recessive disorder, and pregnancy in patients with this condition has been considered risky. We, however, observed a relatively favorable course of pregnancy in a woman with LPI, and even amelioration of symptoms during pregnancy. We believe that this unique observation is not only important for patients with LPI who are facing a choice of child-bearing, but is also of interest to obstetricians and researchers of amino acid metabolism.
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Affiliation(s)
- Hisao Osada
- Department of Obstetrics and Gynecology, Chiba University Hospital, Division of Maternal-Fetal Medicine, Chiba, Japan
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20
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Enns GM, O'Brien WE, Kobayashi K, Shinzawa H, Pellegrino JE. Postpartum "psychosis" in mild argininosuccinate synthetase deficiency. Obstet Gynecol 2005; 105:1244-6. [PMID: 15863597 DOI: 10.1097/01.aog.0000157769.90230.24] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Urea cycle disorders are relatively rare but well-established causes of postpartum coma and death. Such clinical presentations have been reported previously in ornithine transcarbamylase and carbamyl phosphate synthetase deficiencies. CASE We describe a woman, without prior symptoms of metabolic disease, who presented with hyperammonemia and psychiatric symptoms in the postpartum period. Initial diagnoses included acute fatty liver of pregnancy and postpartum psychosis. She was later found to have argininosuccinate synthetase deficiency after further metabolic investigations. Rare heterozygous mutations in the argininosuccinate synthetase gene were identified. CONCLUSION Urea cycle disorders may present initially with postpartum psychiatric symptoms and may represent an underrecognized cause of "postpartum psychosis." We recommend obtaining metabolic studies in women with neurologic or severe psychiatric symptoms in the postpartum period.
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Affiliation(s)
- Gregory M Enns
- Division of Medical Genetics, Department of Pediatrics, Stanford University, Stanford, California 94305-5208, USA.
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21
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Affiliation(s)
- F J Spronsen
- Section of Metabolic Diseases, Groningen University Medical Centre, The Netherlands
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22
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Abstract
Ammonia, normally produced from catabolism of amino acids, is a deadly neurotoxin. As such, the concentration of free ammonia in the blood is very tightly regulated and is exceeded by two orders of magnitude by its physiologic derivative, urea. The normal capacity for urea production far exceeds the rate of free ammonia production by protein catabolism under normal circumstances, such that any increase in free blood ammonia concentration is a reflection of either biochemical or pharmacologic impairment of urea cycle function or fairly extensive hepatic damage. Clinical signs of hyperammonemia occur at concentrations > 60 micromol/L and include anorexia, irritability, lethargy, vomiting, somnolence, disorientation, asterixis, cerebral edema, coma, and death; appearance of these findings is generally proportional to free ammonia concentration, is progressive, and is independent of the primary etiology. Causes of hyperammonemia include genetic defects in the urea cycle ("primary") or organic acidemias ("secondary"), as well as genetic or acquired disorders resulting in significant hepatic dysfunction. Thus, because of the neurotoxic implications of hyperammonemia and the typical absence of other specific laboratory abnormalities, appearance of the clinical signs should trigger an emergent search for elevated blood ammonia concentration.
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Affiliation(s)
- Robert M Cohn
- Department of Pediatrics, Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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23
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Potter MA, Zeesman S, Brennan B, Kobayashi K, Gao HZ, Tabata A, Saheki T, Whelan DT. Pregnancy in a healthy woman with untreated citrullinemia. ACTA ACUST UNITED AC 2004; 129A:77-82. [PMID: 15266621 DOI: 10.1002/ajmg.a.20559] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report the clinical and biochemical data on a second successful pregnancy in a woman with citrullinemia due to argininosuccinate synthetase deficiency (CTLN1). Despite very elevated plasma and urine citrulline and little or no measurable argininosuccinate synthetase enzyme activity on cultured skin fibroblasts, this 29-year-old woman, who was identified through newborn screening, has remained asymptomatic throughout her life. Mutation analysis has recently revealed that she is a compound heterozygote for a known and a novel mutation (IVS15-1G > C and K310Q, respectively). Many newborn screening programs have recently been expanded to include citrullinemia and numerous asymptomatic hypercitrullinemic infants and children have been identified. It is now important to define prognostic indicators that will help with treatment decisions and genetic counseling for these patients. This patient, as the only citrullinemic adult who has been followed prospectively, contributes important information in this regard. In addition, her child was unaffected by the high citrulline levels demonstrated in amniotic fluid and breast milk suggesting that citrulline is not teratogenic. Although pregnancy is an important risk factor for women with CTLN1, it appears that females with citrullinemia can have normal pregnancy outcomes, as long as metabolic crisis is avoided.
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Affiliation(s)
- Murray A Potter
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.
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24
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Abstract
An increasing number of women with inborn errors of metabolism are now reaching child-bearing age. For certain disorders there are maternal risks associated with pregnancy. These may be related to an increased likelihood of metabolic decompensation (e.g. disorders of the urea cycle) or to increased stress to systems already compromised by disease (e.g. cardiomyopathy in GSD III). Detrimental effects upon the fetus may also be caused by maternal disease, as occurs with phenylketonuria, or from medication used to treat the mother's condition. Less commonly, fetal inborn errors may adversely effect the mother's health--e.g. fetal long-chain acyl-CoA dehydrogenase deficiency and the maternal HELLP syndrome (haemolysis, elevated liver enzymes and low platelets) and AFLP (acute fatty liver of pregnancy). Because of the rarity of individual disorders, our knowledge of risks associated with pregnancy is limited. Even for more common inborn errors such as phenylketonuria, there remain a number of questions that have not been fully answered.
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Affiliation(s)
- J H Walter
- Willink Biochemical Genetics Unit, Royal Manchester Children's Hospital, UK.
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25
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Paoloni R, Green T. Hyperammonaemia with normal liver function: An uncommon cause of coma. Emerg Med Australas 1999. [DOI: 10.1046/j.1442-2026.1999.00023.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Mardach MR, Roe K, Cederbaum SD. Successful pregnancy outcome in a woman with argininosuccinate lyase deficiency. J Inherit Metab Dis 1999; 22:102-6. [PMID: 10234604 DOI: 10.1023/a:1005481431955] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- M R Mardach
- Regional Metabolic Service, Southern California Permanente Medical Group, Los Angeles, USA.
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27
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Abstract
We present the favourable outcome of a pregnancy in a woman with maple syrup urine disease. Keeping the maternal plasma levels of the branched-chain amino acids between 100 and 300 mumol/L is compatible with delivery of a normal infant. Leucine tolerance increased progressively from the 22nd week of gestation from 350 to 2100 mg/day. The risk of metabolic decompensation in the postpartum period can be minimized by careful monitoring of the mother after delivery.
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Affiliation(s)
- S Grünewald
- Department of Pediatrics, Heinrich-Heine-University Düsseldorf, Germany
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28
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Van Beers EH, Rings EH, Posthuma G, Dingemanse MA, Taminiau JA, Heymans HS, Einerhand AW, Büller HA, Dekker J. Intestinal carbamoyl phosphate synthase I in human and rat. Expression during development shows species differences and mosaic expression in duodenum of both species. J Histochem Cytochem 1998; 46:231-40. [PMID: 9446830 DOI: 10.1177/002215549804600212] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The clinical importance of carbamoyl phosphate synthase I (CPSI) relates to its capacity to metabolize ammonia, because CPSI deficiencies cause lethal serum ammonia levels. Although some metabolic parameters concerning liver and intestinal CPSI have been reported, the extent to which enterocytes contribute to ammonia conversion remains unclear without a detailed description of its developmental and spatial expression patterns. Therefore, we determined the patterns of enterocytic CPSI mRNA and protein expression in human and rat intestine during embryonic and postnatal development, using in situ hybridization and immunohistochemistry. CPSI protein appeared during human embryogenesis in liver at 31-35 e. d. (embryonic days) before intestine (59 e.d.), whereas in rat CPSI detection in intestine (at 16 e.d.) preceded liver (20 e.d.). During all stages of development there was a good correlation between the expression of CPSI protein and mRNA in the intestinal epithelium. Strikingly, duodenal enterocytes in both species exhibited mosaic CPSI protein expression despite uniform CPSI mRNA expression in the epithelium and the presence of functional mitochondria in all epithelial cells. Unlike rat, CPSI in human embryos was expressed in liver before intestine. Although CPSI was primarily regulated at the transcriptional level, CPSI protein appeared mosaic in the duodenum of both species, possibly due to post-transcriptional regulation.
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Affiliation(s)
- E H Van Beers
- Pediatric Gastroenterology and Nutrition, Department Pediatrics, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
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29
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Summar ML. Molecular genetic research into carbamoyl-phosphate synthase I: molecular defects and linkage markers. J Inherit Metab Dis 1998; 21 Suppl 1:30-9. [PMID: 9686343 DOI: 10.1023/a:1005349306311] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Deficiency of the hepatic enzyme carbamoyl-phosphate synthase I (CPSI), results in lethal or near-lethal hyperammonaemia. As part of our work on CPSI deficiency we have explored the development of markers for prenatal diagnosis, and the determination of molecular defects resulting in CPSI deficiency. We have determined a set of highly informative microsatellite markers flanking the CPSI gene. We have found 14 mutations in individuals with CPSI deficiency. During our mutation studies, we have made extensive use of cell lines not normally expressing CPSI through amplification of 'illegitimate' transcripts. We summarize these findings and review our current understanding of this important enzyme.
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Affiliation(s)
- M L Summar
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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30
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Abstract
We present the outcome of a pregnancy in a woman with mild argininosuccinic lyase deficiency to add to the collective experience of the maternal and fetal effects of urea cycle defects. In females affected with argininosuccinic lyase deficiency, careful clinical and biochemical monitoring of pregnancy will minimize the risk of metabolic decompensation in the perinatal period. Furthermore, it would appear that argininosuccinate is not teratogenic to the development of the human fetus.
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Affiliation(s)
- S Worthington
- Western Sydney Genetics Program, Westmead, Australia
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31
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Zimmer KP, Naim HY, Koch HG, Colombo JP, Rossi R, Schmid KW, Deufel T, Ullrich K, Harms E. Survival after early treatment for carbamyl phosphate synthetase (CPS) I deficiency associated with increase of intramitochondrial CPS I. Lancet 1995; 346:1530-1. [PMID: 7491050 DOI: 10.1016/s0140-6736(95)92055-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The basis for the benefit of early treatment in urea-cycle defects might be an increase in intramitochondrial mutant enzyme in hepatocytes in the postnatal period. In two siblings with carbamyl phosphate synthetase I (CPS I) deficiency, immunoreactive CPS I was greatly reduced in the liver and no residual enzyme activity was detectable. The elder child died at age 4 days, before the diagnosis of CPS I deficiency was established, but in the younger child, age 9 months, treatment was initiated on the 2nd day of life when ammonia concentration was moderately increased, and she has survived. Intramitochondrial CPS I was substantially higher in this sibling than in the elder sister. The different outcome in the younger patient was probably attributable to prompt treatment after early diagnosis.
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Affiliation(s)
- K P Zimmer
- Universitätskinderklinik, Münster, Germany
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32
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Felig DM, Brusilow SW, Boyer JL. Hyperammonemic coma due to parenteral nutrition in a woman with heterozygous ornithine transcarbamylase deficiency. Gastroenterology 1995; 109:282-4. [PMID: 7797025 DOI: 10.1016/0016-5085(95)90295-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ornithine transcarbamylase deficiency is an X-linked disorder of the urea cycle that can cause hyperammonemic encephalopathy in hemizygous males and heterozygous females. Affected females typically limit protein intake in their diet. This case report describes a 36-year-old woman with ulcerative colitis who went into hyperammonemic coma after administration of total parenteral nutrition. A similar episode of coma had occurred 7 years earlier after she delivered a normal boy. Heterozygous ornithine transcarbamylase deficiency was diagnosed based on a positive allopurinol tolerance test result after elevated levels of plasma glutamine and low plasma citrulline were detected. The protein load associated with parenteral alimentation resulted in symptomatic expression of this partial enzyme deficiency in this unique case. Partial ornithine transcarbamylase deficiency must always be considered in adult women and men with hyperammonemia who have normal liver function test results.
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Affiliation(s)
- D M Felig
- Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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