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Citrin deficiency mimicking mitochondrial depletion syndrome. BMC Pediatr 2020; 20:518. [PMID: 33176737 PMCID: PMC7659096 DOI: 10.1186/s12887-020-02409-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/30/2020] [Indexed: 11/10/2022] Open
Abstract
Background Neonatal intrahepatic cholestasis caused by citrin deficiency (CD) is a rare inborn error of metabolism due to variants in the SLC25A13 gene encoding the calcium-binding protein citrin. Citrin is an aspartate-glutamate carrier located within the inner mitochondrial membrane. Case presentation We report on two siblings of Romanian-Vietnamese ancestry with citrin deficiency. Patient 1 is a female who presented at age 8 weeks with cholestasis, elevated lactate levels and recurrent severe hypoglycemia. Diagnosis was made by whole exome sequencing and revealed compound heterozygosity for the frameshift variant c.852_855del, p.Met285Profs*2 and a novel deletion c.(69 + 1_70–1)_(212 + 1_231–1)del in SLC25A13. The girl responded well to dietary treatment with a lactose-free, MCT-enriched formula. Her younger brother (Patient 2) was born 1 year later and also found to be carrying the same gene variants. Dietary treatment from birth was able to completely prevent clinical manifestation until his current age of 4.5 months. Conclusions As CD is a well-treatable disorder it should be ruled out early in the differential diagnosis of neonatal cholestasis. Due to the combination of hepatopathy, lactic acidosis and recurrent hypoglycemia the clinical presentation of CD may resemble hepatic mitochondrial depletion syndrome.
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Häberle J, Burlina A, Chakrapani A, Dixon M, Karall D, Lindner M, Mandel H, Martinelli D, Pintos-Morell G, Santer R, Skouma A, Servais A, Tal G, Rubio V, Huemer M, Dionisi-Vici C. Suggested guidelines for the diagnosis and management of urea cycle disorders: First revision. J Inherit Metab Dis 2019; 42:1192-1230. [PMID: 30982989 DOI: 10.1002/jimd.12100] [Citation(s) in RCA: 249] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 02/06/2023]
Abstract
In 2012, we published guidelines summarizing and evaluating late 2011 evidence for diagnosis and therapy of urea cycle disorders (UCDs). With 1:35 000 estimated incidence, UCDs cause hyperammonemia of neonatal (~50%) or late onset that can lead to intellectual disability or death, even while effective therapies do exist. In the 7 years that have elapsed since the first guideline was published, abundant novel information has accumulated, experience on newborn screening for some UCDs has widened, a novel hyperammonemia-causing genetic disorder has been reported, glycerol phenylbutyrate has been introduced as a treatment, and novel promising therapeutic avenues (including gene therapy) have been opened. Several factors including the impact of the first edition of these guidelines (frequently read and quoted) may have increased awareness among health professionals and patient families. However, under-recognition and delayed diagnosis of UCDs still appear widespread. It was therefore necessary to revise the original guidelines to ensure an up-to-date frame of reference for professionals and patients as well as for awareness campaigns. This was accomplished by keeping the original spirit of providing a trans-European consensus based on robust evidence (scored with GRADE methodology), involving professionals on UCDs from nine countries in preparing this consensus. We believe this revised guideline, which has been reviewed by several societies that are involved in the management of UCDs, will have a positive impact on the outcomes of patients by establishing common standards, and spreading and harmonizing good practices. It may also promote the identification of knowledge voids to be filled by future research.
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Affiliation(s)
- Johannes Häberle
- University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
| | - Alberto Burlina
- Division of Inborn Metabolic Disease, Department of Pediatrics, University Hospital Padua, Padova, Italy
| | - Anupam Chakrapani
- Department of Metabolic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Marjorie Dixon
- Dietetics, Great Ormond Street Hospital for Children, NHS Trust, London, UK
| | - Daniela Karall
- Clinic for Pediatrics, Division of Inherited Metabolic Disorders, Medical University of Innsbruck, Innsbruck, Austria
| | - Martin Lindner
- University Children's Hospital, Frankfurt am Main, Germany
| | - Hanna Mandel
- Institute of Human Genetics and metabolic disorders, Western Galilee Medical Center, Nahariya, Israel
| | - Diego Martinelli
- Division of Metabolism, Bambino Gesù Children's Hospital, Rome, Italy
| | - Guillem Pintos-Morell
- Centre for Rare Diseases, University Hospital Vall d'Hebron, Barcelona, Spain
- CIBERER_GCV08, Research Institute IGTP, Barcelona, Spain
- Universitat Autònoma de Barcelona, Barcelona, Spain
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anastasia Skouma
- Institute of Child Health, Agia Sofia Children's Hospital, Athens, Greece
| | - Aude Servais
- Service de Néphrologie et maladies métaboliques adulte Hôpital Necker 149, Paris, France
| | - Galit Tal
- The Ruth Rappaport Children's Hospital, Rambam Medical Center, Haifa, Israel
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia (IBV-CSIC), Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER), Valencia, Spain
| | - Martina Huemer
- University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
- Department of Paediatrics, Landeskrankenhaus Bregenz, Bregenz, Austria
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Lin Y, Gao H, Lu B, Zhou S, Zheng T, Lin W, Zhu L, Jiang M, Fu Q. Citrullinemia type I is associated with a novel splicing variant, c.773 + 4A > C, in ASS1: a case report and literature review. BMC MEDICAL GENETICS 2019; 20:110. [PMID: 31208364 PMCID: PMC6580464 DOI: 10.1186/s12881-019-0836-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/27/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Citrullinemia type I (CTLN1) is a rare autosomal recessive disorder of the urea cycle caused by a deficiency in the argininosuccinate synthetase (ASS1) enzyme due to mutations in the ASS1 gene. Only a few Chinese patients with CTLN1 have been reported, and ASS1 gene mutations have been identified sporadically in China. CASE PRESENTATION A Chinese family with one member affected with mild CTLN1 was enrolled. Targeted exome sequencing was performed on the proband, and Sanger sequencing was used to validate the detected mutation. We also reviewed the genetic and clinical characteristics of CTLN1 in Chinese patients that have been published to date. Newborn screening showed remarkably increased concentrations of citrulline with elevated ratios of citrulline/arginine and citrulline/phenylalanine, and the patient presented with a speech delay at age three. The urinary organic acid profiles were normal. A novel homozygous splicing variant c.773 + 4A > C in the ASS1 gene was identified in the proband, and it was predicted to affect splicing by in silico analysis. To date, only nine Chinese patients with CTLN1 have been reported, with a total of 15 ASS1 mutations identified and no high frequency or hot spot mutations found; the mutation spectrum of Chinese patients with CTLN1 was heterogeneous. CONCLUSIONS We described a mild Chinese CTLN1 case with a novel homozygous splicing variant c.773 + 4A > C and reviewed previous genotypes and phenotypes in Chinese patients with CTLN1. Thus, our findings contribute to understanding the molecular genetic background and clinical phenotype of CTLN1 in this population.
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Affiliation(s)
- Yiming Lin
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, 362000, Fujian Province, China
| | - Hongzhi Gao
- Department of Central Laboratory, 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, Fujian Province, China
| | - Bin Lu
- Genuine Diagnostics Company Limited, 859 Shixiang West Road, Hangzhou, 310007, Zhejiang Province, China
| | - Shuang Zhou
- Department of Central Laboratory, 2nd Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, Fujian Province, China
| | - Tianwen Zheng
- Department of Pediatrics, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, 362000, Fujian Province, China
| | - Weihua Lin
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, 362000, Fujian Province, China
| | - Lin Zhu
- Genuine Diagnostics Company Limited, 859 Shixiang West Road, Hangzhou, 310007, Zhejiang Province, China
| | - Mengyi Jiang
- Genuine Diagnostics Company Limited, 859 Shixiang West Road, Hangzhou, 310007, Zhejiang Province, China.
| | - Qingliu Fu
- Neonatal Disease Screening Center, Quanzhou Maternity and Children's Hospital, 700 Fengze Street, Quanzhou, 362000, Fujian Province, China.
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4
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Urea cycle disorders-update. J Hum Genet 2019; 64:833-847. [PMID: 31110235 DOI: 10.1038/s10038-019-0614-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 04/14/2019] [Accepted: 04/15/2019] [Indexed: 12/14/2022]
Abstract
The urea cycle is a metabolic pathway for the disposal of excess nitrogen, which arises primarily as ammonia. Nitrogen is essential for growth and life-maintenance, but excessive ammonia leads to life-threatening conditions. The urea cycle disorders (UCDs) comprise diseases presenting with hyperammonemia that arise in either the neonatal period (about 50% of cases) or later. Congenital defects of the enzymes or transporters of the urea cycle cause the disease. This cycle utilizes five enzymes, two of which, carbamoylphosphate synthetase 1 and ornithine transcarbamylase are present in the mitochondrial matrix, whereas the others (argininosuccinate synthetase, argininosuccinate lyase and arginase 1) are present in the cytoplasm. In addition, N-acetylglutamate synthase and at least two transporter proteins are essential to urea cycle function. Severity and age of onset depend on residual enzyme or transporter function and are related to the respective gene mutations. The strategy for therapy is to prevent the irreversible toxicity of high-ammonia exposure to the brain. The pathogenesis and natural course are poorly understood because of the rarity of the disease, so an international registry system and novel clinical trials are much needed. We review here the current concepts of the pathogenesis, diagnostics, including genetics and treatment of UCDs.
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Sugawara D, Taniguchi S, Sato H, Ichihashi K. Diagnosis of citrullinemia type 1 carriage after identification of mild citrullinemia on neonatal screening. Pediatr Int 2018; 60:383-384. [PMID: 29573057 DOI: 10.1111/ped.13515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 12/25/2017] [Accepted: 01/10/2018] [Indexed: 11/26/2022]
Affiliation(s)
- Daisuke Sugawara
- Department of Pediatrics, Saitama Medical Center Jichi Medical University, Saitama, Japan
| | - Shuhei Taniguchi
- Department of Pediatrics, Saitama Medical Center Jichi Medical University, Saitama, Japan
| | - Hiroaki Sato
- Department of Pediatrics, Saitama Medical Center Jichi Medical University, Saitama, Japan
| | - Ko Ichihashi
- Department of Pediatrics, Saitama Medical Center Jichi Medical University, Saitama, Japan
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6
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Diez-Fernandez C, Rüfenacht V, Häberle J. Mutations in the Human Argininosuccinate Synthetase (ASS1) Gene, Impact on Patients, Common Changes, and Structural Considerations. Hum Mutat 2017; 38:471-484. [DOI: 10.1002/humu.23184] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/14/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Carmen Diez-Fernandez
- Division of Metabolism; University Children´s Hospital and Children's Research Center; Zurich Switzerland
| | - Véronique Rüfenacht
- Division of Metabolism; University Children´s Hospital and Children's Research Center; Zurich Switzerland
| | - Johannes Häberle
- Division of Metabolism; University Children´s Hospital and Children's Research Center; Zurich Switzerland
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Martín-Hernández E, Aldámiz-Echevarría L, Castejón-Ponce E, Pedrón-Giner C, Couce ML, Serrano-Nieto J, Pintos-Morell G, Bélanger-Quintana A, Martínez-Pardo M, García-Silva MT, Quijada-Fraile P, Vitoria-Miñana I, Dalmau J, Lama-More RA, Bueno-Delgado MA, Del Toro-Riera M, García-Jiménez I, Sierra-Córcoles C, Ruiz-Pons M, Peña-Quintana LJ, Vives-Piñera I, Moráis A, Balmaseda-Serrano E, Meavilla S, Sanjurjo-Crespo P, Pérez-Cerdá C. Urea cycle disorders in Spain: an observational, cross-sectional and multicentric study of 104 cases. Orphanet J Rare Dis 2014; 9:187. [PMID: 25433810 PMCID: PMC4258263 DOI: 10.1186/s13023-014-0187-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/07/2014] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Advances in the diagnosis and treatment of urea cycle disorders (UCDs) have led to a higher survival rate. The purpose of this study is to describe the characteristics of patients with urea cycle disorders in Spain. METHODS Observational, cross-sectional and multicenter study. Clinical, biochemical and genetic data were collected from patients with UCDs, treated in the metabolic diseases centers in Spain between February 2012 and February 2013, covering the entire Spanish population. Heterozygous mothers of patients with OTC deficiency were only included if they were on treatment due to being symptomatic or having biochemistry abnormalities. RESULTS 104 patients from 98 families were included. Ornithine transcarbamylase deficiency was the most frequent condition (64.4%) (61.2% female) followed by type 1 citrullinemia (21.1%) and argininosuccinic aciduria (9.6%). Only 13 patients (12.5%) were diagnosed in a pre-symptomatic state. 63% of the cases presented with type intoxication encephalopathy. The median ammonia level at onset was 298 μmol/L (169-615). The genotype of 75 patients is known, with 18 new mutations having been described. During the data collection period four patients died, three of them in the early days of life. The median current age is 9.96 years (5.29-18), with 25 patients over 18 years of age. Anthropometric data, expressed as median and z-score for the Spanish population is shown. 52.5% of the cases present neurological sequelae, which have been linked to the type of disease, neonatal onset, hepatic failure at diagnosis and ammonia values at diagnosis. 93 patients are following a protein restrictive diet, 0.84 g/kg/day (0.67-1.10), 50 are receiving essential amino acid supplements, 0.25 g/kg/day (0.20-0.45), 58 arginine, 156 mg/kg/day (109-305) and 45 citrulline, 150 mg/kg/day (105-199). 65 patients are being treated with drugs: 4 with sodium benzoate, 50 with sodium phenylbutyrate, 10 with both drugs and 1 with carglumic acid. CONCLUSIONS Studies like this make it possible to analyze the frequency, natural history and clinical practices in the area of rare diseases, with the purpose of knowing the needs of the patients and thus planning their care.
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Affiliation(s)
- Elena Martín-Hernández
- Pediatric Rares Diseases Unit, Metabolic and Mitochondrial Diseases, Pediatric Department, Hospital Universitario 12 de Octubre. Research Institute (i +12), Madrid, Spain, Avda de Córdoba s/n, 28041, Madrid, Spain.
| | | | | | | | | | | | | | | | | | - María Teresa García-Silva
- Pediatric Rares Diseases Unit, Metabolic and Mitochondrial Diseases, Pediatric Department, Hospital Universitario 12 de Octubre. Research Institute (i +12), Madrid, Spain, Avda de Córdoba s/n, 28041, Madrid, Spain.
| | - Pilar Quijada-Fraile
- Pediatric Rares Diseases Unit, Metabolic and Mitochondrial Diseases, Pediatric Department, Hospital Universitario 12 de Octubre. Research Institute (i +12), Madrid, Spain, Avda de Córdoba s/n, 28041, Madrid, Spain.
| | | | | | | | | | | | | | | | - Mónica Ruiz-Pons
- H.U. Ntra. Sra. de la Candelaria, Santa Cruz de Tenerife, Spain.
| | | | | | | | | | | | | | - Celia Pérez-Cerdá
- CEDEM. Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain.
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8
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Held PK, Haynes CA, De Jesús VR, Baker MW. Development of an assay to simultaneously measure orotic acid, amino acids, and acylcarnitines in dried blood spots. Clin Chim Acta 2014; 436:149-54. [PMID: 24886687 PMCID: PMC4835024 DOI: 10.1016/j.cca.2014.05.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 05/19/2014] [Accepted: 05/21/2014] [Indexed: 12/31/2022]
Abstract
BACKGROUND Orotic aciduria in the presence of hyperammonemia is a key indicator for a defect in the urea cycle, specifically ornithine transcarbamylase (OTC) deficiency. Current newborn screening (NBS) protocols can detect several defects of the urea cycle, but screening for OTC deficiency remains a challenge due to the lack of a suitable assay. The purpose of this study was to develop a high-throughput assay to measure orotic acid in dried blood spot (DBS) specimens as an indicator for urea cycle dysfunction, which can be readily incorporated into routine NBS. METHODS Orotic acid was extracted from DBS punches and analyzed using flow-injection analysis tandem mass spectrometry (FIA-MS/MS) with negative-mode ionization, requiring <2 min/sample run time. This method was then multiplexed into a conventional newborn screening assay for analysis of amino acids, acylcarnitines, and orotic acid. RESULTS We describe 2 assays which can quantify orotic acid in DBS: a stand-alone method and a combined method for analysis of orotic acid, amino acids, and acylcarnitines. Both methods demonstrated orotic acid recovery of 75-85% at multiple levels of enrichment. Precision was also comparable to traditional FIA-MS/MS methods. Analysis of residual presumptively normal NBS specimens demonstrated a 5:1 signal to noise ratio and the average concentration of orotic acid was approximately 1.2 μmol/l. The concentration of amino acids and acylcarnitines as measured by the combined method showed no significant differences when compared to the conventional newborn screening assay. In addition, retrospective analysis of confirmed patients and presumptively normal newborn screening specimens suggests potential for the methods to identify patients with OTC deficiency, as well as other urea cycle defects. CONCLUSION The assays described here quantify orotic acid in DBS using a simple extraction and FIA-MS/MS analysis procedures that can be implemented into current NBS protocols.
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Affiliation(s)
- Patrice K Held
- Wisconsin State Laboratory of Hygiene, 465 Henry Mall, Madison, WI 53706, United States; Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States.
| | - Christopher A Haynes
- Newborn Screening and Molecular Biology Branch, Centers for Disease Control and Prevention, 4770 Buford Highway NE, Atlanta, GA 30341, United States
| | - Víctor R De Jesús
- Newborn Screening and Molecular Biology Branch, Centers for Disease Control and Prevention, 4770 Buford Highway NE, Atlanta, GA 30341, United States
| | - Mei W Baker
- Wisconsin State Laboratory of Hygiene, 465 Henry Mall, Madison, WI 53706, United States; Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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9
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Barends M, Pitt J, Morrissy S, Tzanakos N, Boneh A. Biochemical and molecular characteristics of patients with organic acidaemias and urea cycle disorders identified through newborn screening. Mol Genet Metab 2014; 113:46-52. [PMID: 25047749 DOI: 10.1016/j.ymgme.2014.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/03/2014] [Accepted: 07/03/2014] [Indexed: 01/13/2023]
Abstract
BACKGROUND In recent years it has become clear that newborn screening (NBS) programmes using tandem mass spectrometry identify "patients" with "classical" inborn errors of metabolism who are asymptomatic. This observation raises issues regarding medicalization of "non-diseases," potentially unnecessary treatment and unnecessary anxiety to parents. AIMS This study aims to identify possible markers that may assist in predicting the need for treatment of infants with "classical" organic acidaemias (OA) and urea cycle disorders (UCD) diagnosed through NBS. METHODS Medical records of all patients with classical OA and UCD detected through the Victorian NBS programme from February 2002 to January 2014, or diagnosed clinically between 1990 and January 2002 were retrospectively reviewed. RESULTS Neonatal presentation did not always predict the need for on-going strict treatment. Blood concentrations of amino acids and acyl-carnitines and the changes thereof in follow-up samples correlated with severity in citrullinaemia-I, possibly isovaleric acidaemia but not in argininosuccinic aciduria or propionic acidaemia. Some specific mutations correlate with "attenuated" citrullinaemia-I. Gender may affect clinical outcome in propionic acidaemia. CONCLUSIONS Changes in blood concentration of certain metabolites (amino acids, acyl-carnitines) in the first weeks of life may be predictive of the need for treatment in some disorders but not in others. Mutation analysis may be predictive in some disorders but whether or not this should be considered as second-tier testing in NBS should be discussed separately.
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Affiliation(s)
- M Barends
- Metabolic Research, Murdoch Childrens Research Institute, and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia; Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J Pitt
- Metabolic Research, Murdoch Childrens Research Institute, and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - S Morrissy
- Metabolic Research, Murdoch Childrens Research Institute, and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - N Tzanakos
- Metabolic Research, Murdoch Childrens Research Institute, and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - A Boneh
- Metabolic Research, Murdoch Childrens Research Institute, and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
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10
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Functional analysis of novel splicing and missense mutations identified in the ASS1 gene in classical citrullinemia patients. Clin Chim Acta 2014; 438:323-9. [PMID: 25179242 DOI: 10.1016/j.cca.2014.08.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 08/16/2014] [Accepted: 08/23/2014] [Indexed: 01/23/2023]
Abstract
BACKGROUND Classical citrullinemia (CTLN1) is an inborn error of the urea cycle caused by reduced/abolished activity of argininosuccinate synthetase due to mutations in the ASS1 gene. To determine the pathogenicity of novel variants detected in patients is often a huge challenge in molecular diagnosis. The purpose of our study was to characterize novel ASS1 gene mutations identified in CTLN1 patients. METHODS Exon trapping assay with pSPL3 was used to confirm splice aberrations while bioinformatics structural analysis predicted the possible effects of missense mutations. RESULTS Novel donor site (c.174+1G>A) and missense (p.V141G) mutations were detected in a patient exhibiting a biochemical phenotype only. The splice mutation provoked exon skipping hence the truncated product. The mutation p.V141G, is predicted to disturb a hydrophobic pocket in the ATP binding domain in the ASS. Both mutations are predicted to lower binding of ATP. The second patient presented with early onset neonatal citrullinemia marked by an elevated biochemical profile and a clinical phenotype. Analysis revealed a donor site (c.773+1G>A) mutation leading to both exon skipping and intron retention. Subsequent introduction of premature stop codons would result in severely truncated products likely to be degraded. A previously reported R265C is predicted to distort the citrulline binding site. CONCLUSIONS Three novel mutations are reported in this study. They expand the spectrum of genetic pathology underlying CTLN1. Overall this study provides new insight of CTLN1 and illustrates a comprehensive protocol investigating inborn errors of metabolism at the molecular level.
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11
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Karthikeyan G, Jagadeesh S, Seshadri S, Häberle J. Citrullinemia type 1: genetic diagnosis and prenatal diagnosis in subsequent pregnancy. Indian Pediatr 2014; 50:965-6. [PMID: 24222285 DOI: 10.1007/s13312-013-0239-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Citrullinemia type 1 was diagnosed by tandem mass spectrometry in a full term male neonate who presented with an acute catastrophic collapse on the 3rd day of life. Both parents were identified to be carriers for the exon 15 p Gly390Arg mutation in the argininosuccinate synthetase gene located at chromosome 9q34.1. Chorionic villus sampling and prenatal genetic testing in the subsequent pregnancy revealed an affected fetus resulting in termination of pregnancy.
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Affiliation(s)
- G Karthikeyan
- Womens Center, Coimbatore; Mediscan systems, Chennai, India; and Division of Metabolism, University Childrens Hospital, Steinweiesstrasse, Switzerland. Correspondence to: Dr G Karthikeyan, GK Baby Clinic, 472, Muniappan Koil Street, Coimbatore 641 003, India.
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12
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Molecular genetics of citrullinemia types I and II. Clin Chim Acta 2014; 431:1-8. [DOI: 10.1016/j.cca.2014.01.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/16/2014] [Accepted: 01/18/2014] [Indexed: 12/16/2022]
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13
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Mutation spectrum of the ASS1 gene in Korean patients with citrullinemia type I. Clin Biochem 2013; 46:209-13. [DOI: 10.1016/j.clinbiochem.2012.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/05/2012] [Accepted: 10/06/2012] [Indexed: 11/17/2022]
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14
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Brunetti-Pierri N, Lamance KM, Lewis RA, Craigen WJ. 30-year follow-up of a patient with classic citrullinemia. Mol Genet Metab 2012; 106:248-50. [PMID: 22494546 DOI: 10.1016/j.ymgme.2012.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 03/16/2012] [Accepted: 03/16/2012] [Indexed: 10/28/2022]
Abstract
Citrullinemia is a urea cycle defect requiring long-term care with nutritional and pharmacological management. Despite treatment, morbidity and mortality of this disease remain high, and long-term complications include mild to profound mental retardation, seizures, and growth deficiency. We report a 31-year old woman with classic, neonatal-onset citrullinemia who developed progressive hypertrophic cardiomyopathy and cataracts, neither of which has been recognized previously as a complication of the disease or a consequence of long-term drug treatment.
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Affiliation(s)
- Nicola Brunetti-Pierri
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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15
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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: 362] [Impact Index Per Article: 30.2] [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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Glamuzina E, Marquis-Nicholson R, Knoll D, Love DR, Wilson C. Citrullinaemia type I: a common mutation in the Pacific Island population. J Paediatr Child Health 2011; 47:262-5. [PMID: 21244552 DOI: 10.1111/j.1440-1754.2010.01948.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM The aim of this study was to develop and apply a mutation screening protocol for the ASS1 gene in order to confirm the diagnosis of citrullinaemia type I in neonates with elevated citrulline on expanded newborn screening (E-NBS). METHODS Three patients with an elevated citrulline level were identified via routine E-NBS between January and October 2008. Analysis of the ASS1 gene using a polymerase chain reaction and sequencing-based method was successfully applied to all three patients, together with a rapid mutation-specific detection method. Their clinical progress was followed for 16-22 months. RESULTS All three patients were homozygous for a previously reported missense mutation, c.787G>A (p.Val263Met), associated with a mild or asymptomatic clinical course. CONCLUSIONS As a consequence of E-NBS, an increasing number of neonates with elevated citrulline of uncertain clinical significance are being identified. Rapid sequence analysis of the ASS1 gene can be used to confirm citrullinaemia type I and, increasingly, to infer phenotypic severity. Homozygosity for the same mutation was found in all three patients despite non-consanguinity and variable Pacific Island origin. These data suggest that this mutation may be relatively prevalent in these ethnic groups and imply a possible founder effect.
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Affiliation(s)
- Emma Glamuzina
- Paediatric Metabolic Service, Starship Children's Hospital, Auckland, New Zealand
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Wilcken B. Expanded newborn screening: reducing harm, assessing benefit. J Inherit Metab Dis 2010; 33:S205-10. [PMID: 20440650 DOI: 10.1007/s10545-010-9106-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Revised: 03/28/2010] [Accepted: 04/01/2010] [Indexed: 12/30/2022]
Abstract
Achieving the goals of newborn screening is, as for any screening, a balancing act: getting the maximum benefit from screening while producing the minimum harm. The advent of "expanded" newborn screening, with a large number of disorders detectable using a single test, has also posed problems, not new, but now more obvious. One is the finding of many more cases by screening, the extra cases being largely patients who have attenuated phenotypes and may remain asymptomatic for many years, even throughout life. These may or may not require active management in the short term, but do need lifelong awareness. Additionally, disorders have been included that are now thought benign or largely so. Babies risk being unnecessarily medicalized. Assessing outcome has also proved difficult because of the rarity of some disorders and the impracticality of randomized controlled trials. The requirements for valid studies include the need for case definitions, comparable comparison groups and probably assessment on a whole-population basis. An Australia-wide study of tandem mass spectrometry newborn screening involving 2 million screened and unscreened babies has demonstrated benefits overall to screened patients at age 6 years. The study was too small to provide conclusions for individual disorders other than for medium-chain acyl-CoA dehydrogenase deficiency.
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Affiliation(s)
- Bridget Wilcken
- Biochemical Genetics and Newborn Screening, The Children's Hospital at Westmead, Hawkesbury Road, Westmead, NSW, Australia.
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Marquis-Nicholson R, Glamuzina E, Prosser D, Wilson C, Love DR. Citrullinemia type I: molecular screening of the ASS1 gene by exonic sequencing and targeted mutation analysis. GENETICS AND MOLECULAR RESEARCH 2010; 9:1483-9. [PMID: 20690080 DOI: 10.4238/vol9-3gmr834] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We developed a mutation-screening protocol for the ASS1 gene in order to guide clinical management of neonates with elevated citrulline detected during routine newborn screening. An exon-based amplification and sequencing method was designed and successfully applied to patients to identify disease-associated mutations. The sequencing-based method was applied to three patients with mild or asymptomatic clinical courses. Identification of a homozygous mutation in these patients, c.787G>A (p.Val263Met), led to the development of a tetra-primer ARMS-PCR method that successfully detected the mutation in DNA extracted from blood or from Guthrie card spots.
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Seminara J, Tuchman M, Krivitzky L, Krischer J, Lee HS, LeMons C, Baumgartner M, Cederbaum S, Diaz GA, Feigenbaum A, Gallagher RC, Harding CO, Kerr DS, Lanpher B, Lee B, Lichter-Konecki U, McCandless SE, Merritt JL, Oster-Granite ML, Seashore MR, Stricker T, Summar M, Waisbren S, Yudkoff M, Batshaw ML. Establishing a consortium for the study of rare diseases: The Urea Cycle Disorders Consortium. Mol Genet Metab 2010; 100 Suppl 1:S97-105. [PMID: 20188616 PMCID: PMC2858794 DOI: 10.1016/j.ymgme.2010.01.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/12/2010] [Accepted: 01/12/2010] [Indexed: 12/12/2022]
Abstract
The Urea Cycle Disorders Consortium (UCDC) was created as part of a larger network established by the National Institutes of Health to study rare diseases. This paper reviews the UCDC's accomplishments over the first 6years, including how the Consortium was developed and organized, clinical research studies initiated, and the importance of creating partnerships with patient advocacy groups, philanthropic foundations and biotech and pharmaceutical companies.
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Affiliation(s)
- Jennifer Seminara
- Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
| | - Mendel Tuchman
- Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
| | - Lauren Krivitzky
- Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
| | - Jeffrey Krischer
- Data Management and Coordinating Center, University of South Florida, Tampa, Florida, USA
| | - Hye-Seung Lee
- Data Management and Coordinating Center, University of South Florida, Tampa, Florida, USA
| | - Cynthia LeMons
- National Urea Cycle Disorders Foundation, Pasadena, California, USA
| | | | | | | | | | | | | | | | - Brendan Lanpher
- Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Brendan Lee
- Baylor College of Medicine, Houston, Texas, USA
| | - Uta Lichter-Konecki
- Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
| | | | | | - Mary Lou Oster-Granite
- National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Intellectual and Developmental Disabilities Branch, Bethesda, MD, USA
| | | | | | - Marshall Summar
- Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Marc Yudkoff
- Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Mark L. Batshaw
- Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
- Corresponding author. Phone: 1- 202-476-4007; Fax: 1-202-476-5988; ; Address: Children’s National Medical Center, 111 Michigan Ave, NW, Washington, DC 20010, USA (ML Batshaw)
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21
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Engel K, Höhne W, Häberle J. Mutations and polymorphisms in the human argininosuccinate synthetase (ASS1) gene. Hum Mutat 2009; 30:300-7. [PMID: 19006241 DOI: 10.1002/humu.20847] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Citrullinemia type I is an autosomal recessive disorder that is caused by a deficiency of the urea cycle enzyme argininosuccinate synthetase (ASS1). Deficiency of ASS1 shows various clinical manifestations encompassing severely affected patients with fatal neonatal hyperammonemia as well as asymptomatic individuals with only a biochemical phenotype. This is a comprehensive report of all 87 mutations found to date in the ASS1 gene on chromosome 9q34.1. A large proportion of the mutations (n=27) are described here for the first time. Mutations are distributed throughout exons 3 to 15, most of them being identified in exons 5, 12, 13, and 14. The mutation G390R in exon 15 is the single most common mutation in patients with the classical phenotype. Certain mutations clearly link to specific clinical courses but the clinical phenotype cannot be anticipated in all patients. This update presents a survey of the correlation between mutations in the ASS1 gene and the respective clinical courses as described so far. It also sheds light on the geographic incidence of the mutations. Enzymatic studies have been done in bacterial and human cell systems. However, the prognostic value of genetic aberrations with respect to their effect on protein function and clinical manifestation remains uncertain.
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Affiliation(s)
- Katharina Engel
- Universitätsklinikum Münster, Klinik und Poliklinik für Kinder- und Jugendmedizin, Münster, Germany
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22
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Berning C, Bieger I, Pauli S, Vermeulen T, Vogl T, Rummel T, Höhne W, Koch HG, Rolinski B, Gempel K, Häberle J. Investigation of citrullinemia type I variants by in vitro expression studies. Hum Mutat 2008; 29:1222-7. [PMID: 18473344 DOI: 10.1002/humu.20784] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mild citrullinemia is an allelic variant of classical citrullinemia type I also caused by deficiency of the urea cycle enzyme argininosuccinate synthetase (ASS). Affected patients comprise a biochemical but no clinical phenotype. However, there is no reliable parameter allowing conclusions regarding the course of the disorder or its type of manifestation. The aim of this study was to test the importance of varying levels of ASS residual activities for the severity at diagnosis. Bacterial in vitro expression studies allowed the enzymatic analysis of purified wild-type and the mutant ASS proteins p.Ala118Thr (c.352G>A), p.Trp179Arg (c.535T>C), p.Val263Met (c.787G>A), p.Arg265Cys (c.793C>T), p.Met302Val (c.904A>G), p.Gly324Ser (c.970G>A), p.Gly362Val (c.1085G>T), and p.Gly390Arg (c.1168G>A). In the chosen system, classical mutations do not show any significant enzymatic activity, whereas mutations associated with a mild course yield significant ASS activity levels. The mutation p.Ala118Thr (c.352G>A) impresses by a high residual activity (62%) but a severe reduction of affinity toward the substrates citrulline and aspartate. This mutation was identified in a hitherto healthy female adult with no history of known citrullinemia who had died during the postpartum period from hyperammonemic coma. The results of this study suggest that even a high level of residual ASS activity is not a reliable prognostic marker for an uneventful clinical course. Determination of ASS residual activities, therefore, cannot help in anticipating the risk of metabolic derangement. This study should guide clinicians as well as patients with mild citrullinemia toward a lifelong awareness of the disorder.
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Affiliation(s)
- Christoph Berning
- Universitätsklinikum Münster, Klinik und Poliklinik für Kinder- und Jugendmedizin, Münster, Germany
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Campeau PM, Scriver CR, Mitchell JJ. A 25-year longitudinal analysis of treatment efficacy in inborn errors of metabolism. Mol Genet Metab 2008; 95:11-6. [PMID: 18701331 DOI: 10.1016/j.ymgme.2008.07.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 07/01/2008] [Accepted: 07/01/2008] [Indexed: 12/30/2022]
Abstract
We report here the results of treatment in a panel of 65 inborn errors of metabolism, obtained in the 25th year of a longitudinal project, first reported in 1983. The phenotypic impact of these 65 diseases was scored before and after treatment using a consistent set of parameters, which we have retained to measure change in clinical phenotype throughout the project. We observed significant improvements in the response to treatment for the disease set as a whole. The number of conditions for which there is no response to treatment has progressively decreased; from 31 in 1983, to 20 in 1993, to 17 in 2008. Concomitantly, there has been an increase in the number of conditions that fully respond to treatment (from 8 in 1983 and 1993, to 20 in 2008), and in those for which there is a partial response. Reasons for improved treatment responses include new small molecules, new enzyme replacement therapies, more conditions that can be treated by organ and cell transplantation, and new experimental approaches to substrate reduction and chaperone assisted therapy. However, the most important and new development was not found in one or other particular therapeutic modality but in the access to new knowledge surrounding the individual diseases via the Internet and related resources. Our longitudinal analysis of treatment efficacy for this subset of inborn errors of metabolism continues to constitute a robust and representative assessment of our ability to restore more normal homeostasis in the inborn errors of metabolism.
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Affiliation(s)
- Philippe M Campeau
- Division of Medical Genetics, Department of Pediatrics, A-608, Montreal Children's Hospital, McGill University Health Center, Montreal, Quebec, Canada.
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Tuchman M, Lee B, Lichter-Konecki U, Summar ML, Yudkoff M, Cederbaum SD, Kerr DS, Diaz GA, Seashore MR, Lee HS, McCarter RJ, Krischer JP, Batshaw ML. Cross-sectional multicenter study of patients with urea cycle disorders in the United States. Mol Genet Metab 2008; 94:397-402. [PMID: 18562231 PMCID: PMC2640937 DOI: 10.1016/j.ymgme.2008.05.004] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 05/07/2008] [Accepted: 05/07/2008] [Indexed: 11/23/2022]
Abstract
Inherited urea cycle disorders comprise eight disorders (UCD), each caused by a deficiency of one of the proteins that is essential for ureagenesis. We report on a cross-sectional investigation to determine clinical and laboratory characteristics of patients with UCD in the United States. The data used for the analysis was collected at the time of enrollment of individuals with inherited UCD into a longitudinal observation study. The study has been conducted by the Urea Cycle Disorders Consortium within the Rare Diseases Clinical Research Network (RDCRN) funded by the National Institutes of Health. One-hundred eighty-three patients were enrolled into the study. Ornithine transcarbamylase (OTC) deficiency was the most frequent disorder (55%), followed by argininosuccinic aciduria (16%) and citrullinemia (14%). Seventy-nine percent of the participants were white (16% Latinos), and 6% were African American. Intellectual and developmental disabilities were reported in 39% with learning disabilities (35%) and half had abnormal neurological examination. Sixty-three percent were on a protein restricted diet, 37% were on Na-phenylbutyrate and 5% were on Na-benzoate. Forty-five percent of OTC deficient patients were on L-citrulline, while most patients with citrullinemia (58%) and argininosuccinic aciduria (79%) were on L-arginine. Plasma levels of branched-chain amino acids were reduced in patients treated with ammonia scavenger drugs. Plasma glutamine levels were higher in proximal UCD and in neonatal type disease. The RDCRN allows comprehensive analyses of rare inherited UCD, their frequencies and current medical practices.
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Affiliation(s)
- Mendel Tuchman
- Children's National Medical Center, The George Washington University, School of Medicine, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
| | - Brendan Lee
- Baylor College of Medicine, Houston, TX, USA
| | - Uta Lichter-Konecki
- Children's National Medical Center, The George Washington University, School of Medicine, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
| | | | - Marc Yudkoff
- Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | | | | | - Robert J McCarter
- Children's National Medical Center, The George Washington University, School of Medicine, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
| | | | - Mark L Batshaw
- Children's National Medical Center, The George Washington University, School of Medicine, 111 Michigan Avenue, N.W., Washington, DC 20010, USA
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Wendel U, Burgard P. [Rare metabolic diseases]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2007; 50:1556-63. [PMID: 18026881 DOI: 10.1007/s00103-007-0391-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Rare metabolic diseases are chronic, progressive, present frequently with a life-threatening course and may result in severe handicaps. They demand high diagnostic and therapeutic standards and efforts from physicians and patients. The challenge for society and health systems in dealing with patients affected by one of these diseases is to offer comprehensive service by a multi-professional team of specialists and evidence-based as well as economic (i.e. necessary, sufficient and effective) treatment. Patients and families should be treated in specialized metabolic centres guaranteeing continuous improvement of the scientific and clinical principles of treatment, standardized outcome evaluation, strict quality assurance as well as optimal psychosocial care and counselling. Networking of national and international metabolic centres seems imperative for clinical research in the field of rare metabolic diseases in order to provide adequate sample sizes and to yield substantial results.
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Affiliation(s)
- U Wendel
- Klinik für Allgemeine Pädiatrie, Heinrich-Heine Universität Düsseldorf, BRD.
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26
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Wuyts B, Stove V, Goossens L. Critical sample pretreatment in monitoring dried blood spot citrulline. Clin Chim Acta 2007; 386:105-9. [PMID: 17706623 DOI: 10.1016/j.cca.2007.07.009] [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] [Received: 02/20/2007] [Revised: 07/06/2007] [Accepted: 07/06/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND Plasma Citrulline concentration has been correlated to functional enterocyte mass. Dried blood spot (DBS) analysis using LC-MSMS reduces sample amount needed. We optimized DBS elution to increase precision and accuracy of DBS LC-MSMS analysis. METHOD DBS control samples were eluted in varying pH (2.2-7.0) and for varying times (15-75 min) and Cit, Arg and Orn were analyzed using LC-MSMS, with and without derivatization. In 20 volunteers, the DBS LC-MSMS assay was correlated with a plasma ion exchange HPLC method. RESULTS For Citrulline an extraction optimum was obtained at pH 2.6, whereas lower Arginine concentrations were found using low extraction pH. Increasing elution times lead to increased concentrations. Within-run CV was higher with, compared to without derivatization. No close association could be found between plasma HPLC and DBS LC-MSMS concentrations. CONCLUSION Analysis of amino acids on DBS using LC-MSMS should be optimized regarding the purpose of the assay. In our study, most optimal results were obtained without derivatization and elution in pH 2.6 for 45 min. Cellular amino acids in DBS might influence the correlation of Cit with severity of enteral disorders. Therefore, further evaluation of DBS Cit as a marker for enteral disorders is warranted.
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Affiliation(s)
- Birgitte Wuyts
- Clinical Chemistry, University Hospital Ghent, Gent, Belgium.
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Cipriano LE, Rupar CA, Zaric GS. The cost-effectiveness of expanding newborn screening for up to 21 inherited metabolic disorders using tandem mass spectrometry: results from a decision-analytic model. VALUE IN HEALTH : THE JOURNAL OF THE INTERNATIONAL SOCIETY FOR PHARMACOECONOMICS AND OUTCOMES RESEARCH 2007; 10:83-97. [PMID: 17391418 DOI: 10.1111/j.1524-4733.2006.00156.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
OBJECTIVES In 2005, in Ontario, Canada, newborns were only screened for phenylketonuria (PKU) and hypothyroidism. Tandem mass spectrometry (MS/MS) has since been implemented as a new screening technology because it can screen for PKU and many other diseases simultaneously. We estimated the cost-effectiveness of using this technology to expand the Ontario newborn screening program to screen for each disease independently and for hypothetical bundles of up to 21 metabolic diseases. METHODS We constructed a decision-analytic model to estimate the incremental costs and life-years of survival that can be gained by screening or changing screening technologies. Costs and health benefits were estimated for a cohort of babies born in Ontario in 1 year. Secondary sources and expert opinion were used to estimate the test characteristics, disease prevalence, treatment effectiveness, disease progression rates, and mortality. The London Health Sciences Centre Case Costing Initiative, the Ontario Health Insurance Plan Schedule, and the Ontario Drug Benefits plan formulary were used to estimate costs. RESULTS Changing screening technologies, from the Guthrie test to MS/MS, for PKU detection had an incremental cost of $5,500,000 per life-year (LY) gained. We identified no diseases for which the incremental cost of screening for just that disease was less than $100,000 per LY gained. The incremental costs of screening ranged from $222,000 (HMG-CoA lyase deficiency) to $142,500,000 (glutaric acidemia type II) per LY gained. Screening for a bundle of diseases including PKU and the 14 most cost-effective diseases to screen for cost less than $70,000 per LY gained, and the incremental cost-effectiveness of adding each of the 14 diseases to the bundle was less than $100,000 per LY gained. The incremental cost of adding the 15th most cost-effective disease was $309,400 per LY gained. CONCLUSIONS Early diagnosis and treatment of metabolic disease is important to reduce disease severity and delay or prevent the onset of the disease. Screening at birth reduces the morbidity, mortality, and social burden associated with the irreversible effects of disease on the population. Our analysis suggests that the cost-efficiencies gained by using MS/MS to screen for bundles of diseases rather than just one disease are sufficient to warrant consideration of an expanded screening program. It is, however, not cost-effective to screen for all diseases that can be screened for using this technology.
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Affiliation(s)
- Lauren E Cipriano
- Richard Ivey School of Business, University of Western Ontario, London, ON, Canada
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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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