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Dobritzsch D, Meijer J, Meinsma R, Maurer D, Monavari AA, Gummesson A, Reims A, Cayuela JA, Kuklina N, Benoist JF, Perrin L, Assmann B, Hoffmann GF, Bierau J, Kaindl AM, van Kuilenburg ABP. β-Ureidopropionase deficiency due to novel and rare UPB1 mutations affecting pre-mRNA splicing and protein structural integrity and catalytic activity. Mol Genet Metab 2022; 136:177-185. [PMID: 35151535 DOI: 10.1016/j.ymgme.2022.01.102] [Citation(s) in RCA: 2] [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: 10/20/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 01/04/2023]
Abstract
β-Ureidopropionase is the third enzyme of the pyrimidine degradation pathway and catalyses the conversion of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid to β-alanine and β-aminoisobutyric acid, ammonia and CO2. To date, only a limited number of genetically confirmed patients with a complete β-ureidopropionase deficiency have been reported. Here, we report on the clinical, biochemical and molecular findings of 10 newly identified β-ureidopropionase deficient individuals. Patients presented mainly with neurological abnormalities and markedly elevated levels of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid in urine. Analysis of UPB1, encoding β-ureidopropionase, showed 5 novel missense variants and two novel splice-site variants. Functional expression of the UPB1 variants in mammalian cells showed that recombinant ß-ureidopropionase carrying the p.Ala120Ser, p.Thr129Met, p.Ser300Leu and p.Asn345Ile variant yielded no or significantly decreased β-ureidopropionase activity. Analysis of the crystal structure of human ß-ureidopropionase indicated that the point mutations affect substrate binding or prevent the proper subunit association to larger oligomers and thus a fully functional β-ureidopropionase. A minigene approach showed that the intronic variants c.[364 + 6 T > G] and c.[916 + 1_916 + 2dup] led to skipping of exon 3 and 8, respectively, in the process of UPB1 pre-mRNA splicing. The c.[899C > T] (p.Ser300Leu) variant was identified in two unrelated Swedish β-ureidopropionase patients, indicating that β-ureidopropionase deficiency may be more common than anticipated.
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Affiliation(s)
- Doreen Dobritzsch
- Uppsala University, Department of Chemistry-BMC, Biomedical Center, Uppsala, Sweden
| | - Judith Meijer
- Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology Endocrinology Metabolism, Cancer Center Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam, the Netherlands
| | - Rutger Meinsma
- Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology Endocrinology Metabolism, Cancer Center Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam, the Netherlands
| | | | - Ardeshir A Monavari
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland at Temple Street, Temple Street, Dublin, Ireland
| | - Anders Gummesson
- Sahlgrenska University Hospital, Department of Clinical Genetics and Genomics, Gothenburg, Sweden
| | - Annika Reims
- Queen Silvia Children's Hospital, Gothenburg, Sweden
| | - Jorge A Cayuela
- Sahlgrenska University Hospital, Department of Clinical Genetics and Genomics, Gothenburg, Sweden
| | - Natalia Kuklina
- Drammen Hospital, Pediatric Department/Habilitation Center, Vestre Viken HF, Drammen, Norway
| | - Jean-François Benoist
- Hôpital Universitaire Robert Debré, Service de Biochimie Hormonologie, Paris, France
| | - Laurence Perrin
- Hôpital Universitaire Robert Debré, Service de Biochimie Hormonologie, Paris, France
| | - Birgit Assmann
- University Children's Hospital, University of Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- University Children's Hospital, University of Heidelberg, Heidelberg, Germany
| | - Jörgen Bierau
- Maastricht University Medical Centre, Department of Clinical Genetics, Maastricht, the Netherlands; Department of Clinical Genetics, Erasmus Medical Centre, Rotterdam, the Netherlands
| | - Angela M Kaindl
- Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Center for Chronically Sick Children, Institute for Cell and Neurobiology, Berlin, Germany
| | - André B P van Kuilenburg
- Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Gastroenterology Endocrinology Metabolism, Cancer Center Amsterdam, Laboratory Genetic Metabolic Diseases, Amsterdam, the Netherlands.
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Cheng G, Reisinger SA, Shields PG, Hatsukami DK, Balbo S, Hecht SS. Quantitation by liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry of DNA adducts derived from methyl glyoxal and carboxyethylating agents in leukocytes of smokers and non-smokers. Chem Biol Interact 2020; 327:109140. [PMID: 32442416 PMCID: PMC7682731 DOI: 10.1016/j.cbi.2020.109140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 05/19/2020] [Indexed: 12/17/2022]
Abstract
A liquid chromatograpy-nanoelectrospray ionization-high resolution tandem mass spectrometry (LC-NSI-HRMS/MS) method was developed for quantitation of the DNA adducts 7-(2'-carboxyethyl)guanine (7-2'-CEG) and N2-(1'-carboxyethyl)guanine (N2-1'-CEG), as their methyl esters, in human leukocyte DNA from smokers and non-smokers. 7-2'-CEG has been previously identified in all human liver samples analyzed and is formed from an unknown carboxyethylating agent while N2-1'-CEG is formed from the advanced glycation endproduct methyl glyoxal. The method was applied for the analysis of these two DNA adducts in leukocyte DNA from 20 smokers and 20 non-smokers, in part to test the hypothesis that 7-2'-CEG could be formed by endogenous nitrosation, as previously observed in rats treated with nitrosodihydrouracil and nitrite. Levels of 7-2'-CEG (mean ± S.D.) were 0.6 ± 0.2 pmol/μmol dG in smokers and 0.5 ± 0.2 pmol/μmol dG in non-smokers, while those of N2-1'-CEG were 4.5 ± 1.9 pmol/μmol dG in smokers and 4.6 ± 2 pmol/μmol dG in non-smokers. These results did not support our hypothesis that endogenous nitrosation of dihydrouracil in smokers leads to higher levels of 7-2'-CEG in leukocyte DNA than in non-smokers. However the study provides the first data on levels of these DNA adducts in human leukocyte DNA, and the LC-NSI-HRMS/MS method developed for their quantitation could be important for future studies of DNA damage by methyl glyoxal.
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Affiliation(s)
- Guang Cheng
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Sarah A Reisinger
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
| | - Peter G Shields
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA
| | | | - Silvia Balbo
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Stephen S Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, 55455, USA.
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Yin P, Jia A, Heimann K, Zhang M, Liu X, Zhang W, Liu C. Hot water pretreatment-induced significant metabolite changes in the sea cucumber Apostichopus japonicus. Food Chem 2020; 314:126211. [PMID: 31982856 DOI: 10.1016/j.foodchem.2020.126211] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/19/2019] [Accepted: 01/12/2020] [Indexed: 12/27/2022]
Abstract
Hot water pretreatment of sea cucumbers potentially changes nutritional benefits. This study aimed to quantify hot water pretreatment-induced changes in metabolite profiles of sea cucumber body walls. ICP-OES, GC-MS, and LC-MS analyses of untreated- (UT-BW), hot water-treated body walls (HW-BW) of Apostichopus japonicus, and the hot water extract (HW-E) determined significant losses of minerals (25-50% w/w), protein (~11% w/w), carbohydrate (33% w/w), saponins (~41% w/w), and spermidine (100%), a potential antipsychotic from hot water-treated samples. Multivariate comparisons of HW-BW with UT-BW and HW-BW with HW-E showed increases in amino acids and fatty acids, suggesting hot water-induced degradation or transformation or easier extraction of protein, lipid or other components. Presence of 80 to 88.5% of compounds in the HW-E and lower DHA, EPA and glycerophospholipids levels in HW-BW suggested extraction of these metabolites. These data indicate that novel processing technologies are required to preserve the full nutritional benefits of sea cucumbers.
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Affiliation(s)
- Peipei Yin
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China; China-Australia Joint Laboratory for Native Bioresource Industry Innovation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China
| | - Airong Jia
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China; China-Australia Joint Laboratory for Native Bioresource Industry Innovation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China.
| | - Kirsten Heimann
- China-Australia Joint Laboratory for Native Bioresource Industry Innovation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China; Centre for Marine Bioproducts Development, College of Medicine and Public Health, Flinders University, Adelaide, SA 5042, Australia
| | - Miansong Zhang
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China; China-Australia Joint Laboratory for Native Bioresource Industry Innovation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China
| | - Xin Liu
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China; China-Australia Joint Laboratory for Native Bioresource Industry Innovation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China
| | - Wei Zhang
- China-Australia Joint Laboratory for Native Bioresource Industry Innovation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China; Centre for Marine Bioproducts Development, College of Medicine and Public Health, Flinders University, Adelaide, SA 5042, Australia.
| | - Changheng Liu
- Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China; China-Australia Joint Laboratory for Native Bioresource Industry Innovation, Qilu University of Technology (Shandong Academy of Sciences), Jinan, Shandong 250103, China
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Deficiency of perforin and hCNT1, a novel inborn error of pyrimidine metabolism, associated with a rapidly developing lethal phenotype due to multi-organ failure. Biochim Biophys Acta Mol Basis Dis 2019; 1865:1182-1191. [PMID: 30658162 DOI: 10.1016/j.bbadis.2019.01.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/07/2019] [Accepted: 01/09/2019] [Indexed: 01/25/2023]
Abstract
Pyrimidine nucleotides are essential for a vast number of cellular processes and dysregulation of pyrimidine metabolism has been associated with a variety of clinical abnormalities. Inborn errors of pyrimidine metabolism affecting enzymes in the pyrimidine de novo and degradation pathway have been identified but no patients have been described with a deficiency in proteins affecting the cellular import of ribonucleosides. In this manuscript, we report the elucidation of the genetic basis of the observed uridine-cytidineuria in a patient presenting with fever, hepatosplenomegaly, persistent lactate acidosis, severely disturbed liver enzymes and ultimately multi-organ failure. Sequence analysis of genes encoding proteins directly involved in the metabolism of uridine and cytidine showed two variants c.1528C > T (p.R510C) and c.1682G > A (p.R561Q) in SLC28A1, encoding concentrative nucleotide transporter 1 (hCNT1). Functional analysis showed that these variants affected the three-dimensional structure of hCNT1, altered glycosylation and decreased the half-life of the mutant proteins which resulted in impaired transport activity. Co-transfection of both variants, mimicking the trans disposition of c.1528C > T (p.R510C) and c.1682G > A (p.R561Q) in the patient, significantly impaired hCNT1 biological function. Whole genome sequencing identified two pathogenic variants c.50delT; p.(Leu17Argfs*34) and c.853_855del; p.(Lys285del) in the PRF1 gene, indicating that our patient was also suffering from Familial Hemophagocytic Lymphohistiocytosis type 2. The identification of two co-existing monogenic defects might have resulted in a blended phenotype. Thus, the clinical presentation of isolated hCNT1 deficiency remains to be established.
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Nakajima Y, Meijer J, Dobritzsch D, Ito T, Zhang C, Wang X, Watanabe Y, Tashiro K, Meinsma R, Roelofsen J, Zoetekouw L, van Kuilenburg ABP. Dihydropyrimidinase deficiency in four East Asian patients due to novel and rare DPYS mutations affecting protein structural integrity and catalytic activity. Mol Genet Metab 2017; 122:216-222. [PMID: 29054612 DOI: 10.1016/j.ymgme.2017.10.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/09/2017] [Accepted: 10/09/2017] [Indexed: 01/07/2023]
Abstract
Dihydropyrimidinase (DHP) is the second enzyme of the pyrimidine degradation pathway and catalyzes the ring opening of 5,6-dihydrouracil and 5,6-dihydrothymine. To date, only 31 genetically confirmed patients with a DHP deficiency have been reported and the clinical, biochemical and genetic spectrum of DHP deficient patients is, therefore, still largely unknown. Here, we show that 4 newly identified DHP deficient patients presented with strongly elevated levels of 5,6-dihydrouracil and 5,6-dihydrothymine in urine and a highly variable clinical presentation, ranging from asymptomatic to infantile spasm and reduced white matter and brain atrophy. Analysis of the DHP gene (DPYS) showed the presence of 8 variants including 4 novel/rare missense variants and one novel deletion. Functional analysis of recombinantly expressed DHP mutants carrying the p.M250I, p.H295R, p.Q334R, p.T418I and the p.R490H variant showed residual DHP activities of 2.0%, 9.8%, 9.7%, 64% and 0.3%, respectively. The crystal structure of human DHP indicated that all point mutations were likely to cause rearrangements of loops shaping the active site, primarily affecting substrate binding and stability of the enzyme. The observation that the identified mutations were more prevalent in East Asians and the Japanese population indicates that DHP deficiency may be more common than anticipated in these ethnic groups.
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Affiliation(s)
- Yoko Nakajima
- Fujita Health University School of Medicine, Department of Pediatrics, Toyoake 470-1192, Japan; Academic Medical Center, Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, 1105, AZ, Amsterdam, The Netherlands
| | - Judith Meijer
- Academic Medical Center, Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, 1105, AZ, Amsterdam, The Netherlands
| | - Doreen Dobritzsch
- Uppsala University, Department of Chemistry, Biomedical Center, S-751 24 Uppsala, Sweden
| | - Tetsuya Ito
- Fujita Health University School of Medicine, Department of Pediatrics, Toyoake 470-1192, Japan
| | - Chunhua Zhang
- MILS International, Department of Research and Development, Kanazawa 921-8105, Japan
| | - Xu Wang
- Beijing Children's Hospital, Capital University of Medical Sciences, Department of Neurology, Beijing 100045, China
| | - Yoriko Watanabe
- Kurume University, School of Medicine, Department of Pediatrics, Kurume 830-0011, Japan
| | - Kyoko Tashiro
- Kurume University, School of Medicine, Research Institute of Medical Mass Spectrometry, Kurume 830-0011, Japan
| | - Rutger Meinsma
- Academic Medical Center, Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, 1105, AZ, Amsterdam, The Netherlands
| | - Jeroen Roelofsen
- Academic Medical Center, Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, 1105, AZ, Amsterdam, The Netherlands
| | - Lida Zoetekouw
- Academic Medical Center, Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, 1105, AZ, Amsterdam, The Netherlands
| | - André B P van Kuilenburg
- Academic Medical Center, Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, 1105, AZ, Amsterdam, The Netherlands.
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Henricks LM, Siemerink EJ, Rosing H, Meijer J, Goorden SM, Polstra AM, Zoetekouw L, Cats A, Schellens JH, van Kuilenburg AB. Capecitabine-based treatment of a patient with a novelDPYDgenotype and complete dihydropyrimidine dehydrogenase deficiency. Int J Cancer 2017; 142:424-430. [DOI: 10.1002/ijc.31065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/16/2017] [Accepted: 09/08/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Linda M. Henricks
- Division of Pharmacology and Division of Clinical Pharmacology, Department of Medical Oncology; The Netherlands Cancer Institute; Amsterdam The Netherlands
| | - Ester J.M. Siemerink
- Department of Internal Medicine; Ziekenhuis Groep Twente (ZGT); Hengelo The Netherlands
| | - Hilde Rosing
- Department of Pharmacy and Pharmacology; The Netherlands Cancer Institute; Amsterdam The Netherlands
| | - Judith Meijer
- Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Clinical Genetics; Academic Medical Center, University of Amsterdam; Amsterdam The Netherlands
| | - Susan M.I. Goorden
- Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Clinical Genetics; Academic Medical Center, University of Amsterdam; Amsterdam The Netherlands
| | - Abeltje M. Polstra
- Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Clinical Genetics; Academic Medical Center, University of Amsterdam; Amsterdam The Netherlands
- Department of Clinical Genetics; VU University Medical Center; Amsterdam The Netherlands
| | - Lida Zoetekouw
- Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Clinical Genetics; Academic Medical Center, University of Amsterdam; Amsterdam The Netherlands
| | - Annemieke Cats
- Department of Gastrointestinal Oncology; The Netherlands Cancer Institute; Amsterdam The Netherlands
| | - Jan H.M. Schellens
- Division of Pharmacology and Division of Clinical Pharmacology, Department of Medical Oncology; The Netherlands Cancer Institute; Amsterdam The Netherlands
- Utrecht Institute for Pharmaceutical Sciences, Utrecht University; Utrecht The Netherlands
| | - André B.P. van Kuilenburg
- Laboratory Genetic Metabolic Diseases, Departments of Clinical Chemistry and Clinical Genetics; Academic Medical Center, University of Amsterdam; Amsterdam The Netherlands
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Kuilenburg ABPV, Meijer J, Tanck MWT, Dobritzsch D, Zoetekouw L, Dekkers LL, Roelofsen J, Meinsma R, Wymenga M, Kulik W, Büchel B, Hennekam RCM, Largiadèr CR. Phenotypic and clinical implications of variants in the dihydropyrimidine dehydrogenase gene. Biochim Biophys Acta Mol Basis Dis 2016; 1862:754-762. [PMID: 26804652 DOI: 10.1016/j.bbadis.2016.01.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/21/2015] [Accepted: 01/08/2016] [Indexed: 12/22/2022]
Abstract
Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of the pyrimidine bases uracil, thymine and the antineoplastic agent 5-fluorouracil. Genetic variations in the gene encoding DPD (DPYD) have emerged as predictive risk alleles for 5FU-associated toxicity. Here we report an in-depth analysis of genetic variants in DPYD and their consequences for DPD activity and pyrimidine metabolites in 100 Dutch healthy volunteers. 34 SNPs were detected in DPYD and 15 SNPs were associated with altered plasma concentrations of pyrimidine metabolites. DPD activity was significantly associated with the plasma concentrations of uracil, the presence of a specific DPYD mutation (c.1905+1G>A) and the combined presence of three risk variants in DPYD (c.1905+1G>A, c.1129-5923C>G, c.2846A>T), but not with an altered uracil/dihydrouracil (U/UH2) ratio. Various haplotypes were associated with different DPD activities (haplotype D3, a decreased DPD activity; haplotype F2, an increased DPD activity). Functional analysis of eight recombinant mutant DPD enzymes showed a reduced DPD activity, ranging from 35% to 84% of the wild-type enzyme. Analysis of a DPD homology model indicated that the structural effect of the novel p.G401R mutation is most likely minor. The clinical relevance of the p.D949V mutation was demonstrated in a cancer patient heterozygous for the c.2846A>T mutation and a novel nonsense mutation c.1681C>T (p.R561X), experiencing severe grade IV toxicity. Our studies showed that the endogenous levels of uracil and the U/UH2 ratio are poor predictors of an impaired DPD activity. Loading studies with uracil to identify patients with a DPD deficiency warrants further investigation.
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Affiliation(s)
- André B P van Kuilenburg
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands.
| | - Judith Meijer
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Michael W T Tanck
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Doreen Dobritzsch
- Department of Chemistry, Biomedical Center, Uppsala University, S-751 24 Uppsala, Sweden
| | - Lida Zoetekouw
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Jeroen Roelofsen
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Rutger Meinsma
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Machteld Wymenga
- Department of Oncology, Medisch Spectrum Twente, Enschede, The Netherlands
| | - Wim Kulik
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Barbara Büchel
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Raoul C M Hennekam
- Departments of Clinical Chemistry, Pediatrics, Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, The Netherlands
| | - Carlo R Largiadèr
- Department of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Altered Pre-mRNA Splicing Caused by a Novel Intronic Mutation c.1443+5G>A in the Dihydropyrimidinase (DPYS) Gene. Int J Mol Sci 2016; 17:ijms17010086. [PMID: 26771602 PMCID: PMC4730329 DOI: 10.3390/ijms17010086] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 12/28/2015] [Accepted: 01/04/2016] [Indexed: 11/17/2022] Open
Abstract
Dihydropyrimidinase (DHP) deficiency is an autosomal recessive disease caused by mutations in the DPYS gene. Patients present with highly elevated levels of dihydrouracil and dihydrothymine in their urine, blood and cerebrospinal fluid. The analysis of the effect of mutations in DPYS on pre-mRNA splicing is hampered by the fact that DHP is primarily expressed in liver and kidney cells. The minigene approach can detect mRNA splicing aberrations using cells that do not express the endogenous mRNA. We have used a minigene-based approach to analyze the effects of a presumptive pre-mRNA splicing mutation in two newly identified Chinese pediatric patients with DHP deficiency. Mutation analysis of DPYS showed that both patients were compound heterozygous for a novel intronic mutation c.1443+5G>A in intron 8 and a previously described missense mutation c.1001A>G (p.Q334R) in exon 6. Wild-type and the mutated minigene constructs, containing exons 7, 8 and 9 of DPYS, yielded different splicing products after expression in HEK293 cells. The c.1443+5G>A mutation resulted in altered pre-mRNA splicing of the DPYS minigene construct with full skipping of exon 8. Analysis of the DHP crystal structure showed that the deletion of exon 8 severely affects folding, stability and homooligomerization of the enzyme as well as disruption of the catalytic site. Thus, the analysis suggests that the c.1443+5G>A mutation results in aberrant splicing of the pre-mRNA encoding DHP, underlying the DHP deficiency in two unrelated Chinese patients.
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van Staveren MC, van Kuilenburg ABP, Guchelaar HJ, Meijer J, Punt CJA, de Jong RS, Gelderblom H, Maring JG. Evaluation of an oral uracil loading test to identify DPD-deficient patients using a limited sampling strategy. Br J Clin Pharmacol 2016; 81:553-61. [PMID: 26551538 DOI: 10.1111/bcp.12821] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 10/27/2015] [Accepted: 11/02/2015] [Indexed: 11/27/2022] Open
Abstract
AIM Dihydropyrimidine dehydrogenase (DPD) deficiency can lead to severe toxicity following 5-fluorouracil (5FU) or capecitabine (CAP) treatment. Uracil (U) can be used as a probe to determine systemic DPD activity. The present study was performed to assess the sensitivity and specificity of a U loading dose for detecting DPD deficiency. METHODS Cancer patients with Common Toxicity Score (CTC) grade III or IV toxicity after the first or second cycle of 5-FU or CAP treatment were asked to participate. Based on DPD activity in PBMCs, patients were divided into two groups: DPD activity in peripheral blood mononuclear cells (PBMCs) <5 nmol mg(-1) *h(-1) (deficient group) and ≥ 5 nmol mg(-1) *h(-1) . U 500 mg m(-2) was administered orally and plasma concentrations of U and dihydrouracil (DHU) were determined. In the deficient group, polymerase chain reaction amplification of all 23 coding exons and flanking intronic regions of DPYD was performed. A U pharmacokinetic model was developed and used to determine the maximum enzymatic conversion capacity (Vmax ) of the DPD enzyme for each patient. The sensitivity and specificity of Vmax, U concentration and the U/DHU concentration ratio were determined. RESULTS A total of 47 patients were included (19 DPD deficient, 28 DPD normal). Of the pharmacokinetic parameters investigated, a sensitivity and specificity of 80% and 98%, respectively, was obtained for the U/DHU ratio at t = 120 min. CONCLUSIONS The high sensitivity of the U/DHU ratio at t = 120 min for detecting DPD deficiency, as defined by DPD activity in PBMCs, showed that the oral U loading dose can effectively identify patients with reduced DPD activity.
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Affiliation(s)
- Maurice C van Staveren
- Department of Clinical Pharmacy, Treant Healthgroup, Scheper Hospital, Emmen, The Netherlands
| | | | - Henk-Jan Guchelaar
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Judith Meijer
- Laboratory of Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands
| | - Cornelis J A Punt
- Department of Medical Oncology, Academic Medical Center, Amsterdam, The Netherlands
| | - Robert S de Jong
- Department of Oncology, Martini Hospital, Groningen, The Netherlands
| | - Hans Gelderblom
- Department of Medical Oncology, Leiden University Medical Center, University Hospital of Leiden, Leiden, The Netherlands
| | - Jan Gerard Maring
- Department of Pharmacy, Isala Diaconessen Hospital, Meppel and Bethesda Hospital,Hoogeveen, The Netherlands
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Nakajima Y, Meijer J, Dobritzsch D, Ito T, Meinsma R, Abeling NGGM, Roelofsen J, Zoetekouw L, Watanabe Y, Tashiro K, Lee T, Takeshima Y, Mitsubuchi H, Yoneyama A, Ohta K, Eto K, Saito K, Kuhara T, van Kuilenburg ABP. Clinical, biochemical and molecular analysis of 13 Japanese patients with β-ureidopropionase deficiency demonstrates high prevalence of the c.977G > A (p.R326Q) mutation [corrected]. J Inherit Metab Dis 2014; 37:801-12. [PMID: 24526388 PMCID: PMC4158181 DOI: 10.1007/s10545-014-9682-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/18/2014] [Accepted: 01/21/2014] [Indexed: 11/13/2022]
Abstract
β-ureidopropionase (βUP) deficiency is an autosomal recessive disease characterized by N-carbamyl-β-amino aciduria. To date, only 16 genetically confirmed patients with βUP deficiency have been reported. Here, we report on the clinical, biochemical and molecular findings of 13 Japanese βUP deficient patients. In this group of patients, three novel missense mutations (p.G31S, p.E271K, and p.I286T) and a recently described mutation (p.R326Q) were identified. The p.R326Q mutation was detected in all 13 patients with eight patients being homozygous for this mutation. Screening for the p.R326Q mutation in 110 Japanese individuals showed an allele frequency of 0.9 %. Transient expression of mutant βUP enzymes in HEK293 cells showed that the p.E271K and p.R326Q mutations cause profound decreases in activity (≤ 1.3 %). Conversely, βUP enzymes containing the p.G31S and p.I286T mutations possess residual activities of 50 and 70 %, respectively, suggesting we cannot exclude the presence of additional mutations in the non-coding region of the UPB1 gene. Analysis of a human βUP homology model revealed that the effects of the mutations (p.G31S, p.E271K, and p.R326Q) on enzyme activity are most likely linked to improper oligomer assembly. Highly variable phenotypes ranging from neurological involvement (including convulsions and autism) to asymptomatic, were observed in diagnosed patients. High prevalence of p.R326Q in the normal Japanese population indicates that βUP deficiency is not as rare as generally considered and screening for βUP deficiency should be included in diagnosis of patients with unexplained neurological abnormalities.
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Affiliation(s)
- Yoko Nakajima
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Academic Medical Center, 1105 AZ, Amsterdam, Netherlands,
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11
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Meijer J, Nakajima Y, Zhang C, Meinsma R, Ito T, Van Kuilenburg ABP. Identification of a novel synonymous mutation in the human β -Ureidopropionase Gene UPB1 affecting pre-mRNA splicing. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2014; 32:639-45. [PMID: 24328561 DOI: 10.1080/15257770.2013.847189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
β-Ureidopropionase is the third enzyme of the pyrimidine degradation pathway and it catalyzes the conversion of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid to β-alanine and β-aminoisobutyric acid, respectively, and ammonia and CO2. To date, only 16 genetically confirmed patients with a complete ß-ureidopropionase deficiency have been reported. Here, we report the clinical, biochemical, and molecular analysis of a newly identified patient with β-ureidopropionase deficiency. Mutation analysis of the UPB1 gene showed that the patient was compound heterozygous for a novel synonymous mutation c.93C >T (p.Gly31Gly) in exon 1 and a previously described missense mutation c.977G >A (p.Arg326Gln) in exon 9. The in silico predicted effect of the synonymous mutation p.Gly31Gly on pre-mRNA splicing was investigated using a minigene approach. Wild-type and the mutated minigene constructs, containing the entire exon 1, intron 1, and exon 2 of UPB1, yielded different splicing products after expression in HEK293 cells. The c.93C >T (p.Gly31Gly) mutation resulted in altered pre-mRNA splicing of the UPB1 minigene construct and a deletion of the last 13 nucleotides of exon 1. This deletion (r.92_104delGCAAGGAACTCAG) results in a frame shift and the generation of a premature stop codon (p.Lys32SerfsX31). Using a minigene approach, we have thus identified the first synonymous mutation in the UPB1 gene, creating a cryptic splice-donor site affecting pre-mRNA splicing.
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Affiliation(s)
- J Meijer
- a Laboratory of Genetic Metabolic Diseases , Academic Medical Center , Amsterdam , The Netherlands
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12
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Wang M, Cheng G, Khariwala SS, Bandyopadhyay D, Villalta PW, Balbo S, Hecht SS. Evidence for endogenous formation of the hepatocarcinogen N-nitrosodihydrouracil in rats treated with dihydrouracil and sodium nitrite: a potential source of human hepatic DNA carboxyethylation. Chem Biol Interact 2013; 206:83-9. [PMID: 23911671 PMCID: PMC3839423 DOI: 10.1016/j.cbi.2013.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/08/2013] [Accepted: 07/23/2013] [Indexed: 10/26/2022]
Abstract
An earlier study demonstrated that hydrolysates of all human liver DNA samples analyzed contain the DNA adduct 7-(2'-carboxyethyl)guanine (7-CEGua) with an average level of 74.6 adducts per 10(9) nucleotides. One possible source of this DNA adduct would be endogenous nitrosation of the normal pyrimidine metabolites dihydrouracil (DHU) and β-ureidopropionic acid (β-UPA), yielding the corresponding nitroso compounds N-nitrosodihydrouracil, a potent hepatocarcinogen, and N-nitroso-β-ureidopropionic acid. Another potential source would be reaction of endogenously formed acrylic acid with DNA. We tested these hypotheses in a study in which rats were treated with NaNO2 in the drinking water, alone, or in combination with dietary DHU or β-UPA, or with acrylic acid in the drinking water, for either 2 or 4 weeks. Hepatic DNA from these rats was analyzed for 7-CEGua, using liquid chromatography-tandem mass spectrometry-selected reaction monitoring with confirmation by high resolution mass spectrometry. The results demonstrated consistent statistically significant increases of 7-CEGua in hepatic DNA of the rats treated with the combination of NaNO2 and DHU compared to the corresponding controls, while the other treatments gave variable results. These results support the hypothesis that endogenous nitrosation of DHU could be a major source of 7-CEGua in human hepatic DNA. Development of methodology for analysis of 7-CEGua in human leukocyte DNA is also reported, which will allow testing of this hypothesis in epidemiologic and clinical studies.
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Affiliation(s)
- Mingyao Wang
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Guang Cheng
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Samir S. Khariwala
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | | | - Peter W. Villalta
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Silvia Balbo
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA
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Coudoré F, Roche D, Lefeuvre S, Faussot D, Billaud EM, Loriot MA, Beaune P. Validation of an Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometric Method for Quantifying Uracil and 5,6-Dihydrouracil in Human Plasma. J Chromatogr Sci 2012; 50:877-84. [DOI: 10.1093/chromsci/bms085] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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14
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van Kuilenburg ABP, Dobritzsch D, Meijer J, Krumpel M, Selim LA, Rashed MS, Assmann B, Meinsma R, Lohkamp B, Ito T, Abeling NGGM, Saito K, Eto K, Smitka M, Engvall M, Zhang C, Xu W, Zoetekouw L, Hennekam RCM. ß-ureidopropionase deficiency: phenotype, genotype and protein structural consequences in 16 patients. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1096-108. [PMID: 22525402 DOI: 10.1016/j.bbadis.2012.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 03/29/2012] [Accepted: 04/09/2012] [Indexed: 12/26/2022]
Abstract
ß-ureidopropionase is the third enzyme of the pyrimidine degradation pathway and catalyzes the conversion of N-carbamyl-ß-alanine and N-carbamyl-ß-aminoisobutyric acid to ß-alanine and ß-aminoisobutyric acid, ammonia and CO(2). To date, only five genetically confirmed patients with a complete ß-ureidopropionase deficiency have been reported. Here, we report on the clinical, biochemical and molecular findings of 11 newly identified ß-ureidopropionase deficient patients as well as the analysis of the mutations in a three-dimensional framework. Patients presented mainly with neurological abnormalities (intellectual disabilities, seizures, abnormal tonus regulation, microcephaly, and malformations on neuro-imaging) and markedly elevated levels of N-carbamyl-ß-alanine and N-carbamyl-ß-aminoisobutyric acid in urine and plasma. Analysis of UPB1, encoding ß-ureidopropionase, showed 6 novel missense mutations and one novel splice-site mutation. Heterologous expression of the 6 mutant enzymes in Escherichia coli showed that all mutations yielded mutant ß-ureidopropionase proteins with significantly decreased activity. Analysis of a homology model of human ß-ureidopropionase generated using the crystal structure of the enzyme from Drosophila melanogaster indicated that the point mutations p.G235R, p.R236W and p.S264R lead to amino acid exchanges in the active site and therefore affect substrate binding and catalysis. The mutations L13S, R326Q and T359M resulted most likely in folding defects and oligomer assembly impairment. Two mutations were identified in several unrelated ß-ureidopropionase patients, indicating that ß-ureidopropionase deficiency may be more common than anticipated.
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Affiliation(s)
- André B P van Kuilenburg
- Academic Medical Center, Emma Children's Hospital, Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, 1105 AZ Amsterdam, The Netherlands.
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15
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Büchel B, Rhyn P, Schürch S, Bühr C, Amstutz U, Largiadèr CR. LC-MS/MS method for simultaneous analysis of uracil, 5,6-dihydrouracil, 5-fluorouracil and 5-fluoro-5,6-dihydrouracil in human plasma for therapeutic drug monitoring and toxicity prediction in cancer patients. Biomed Chromatogr 2012; 27:7-16. [PMID: 22454320 DOI: 10.1002/bmc.2741] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 02/24/2012] [Accepted: 02/27/2012] [Indexed: 11/08/2022]
Abstract
The chemotherapeutic drug 5-fluorouracil (5-FU) is widely used for treating solid tumors. Response to 5-FU treatment is variable with 10-30% of patients experiencing serious toxicity partly explained by reduced activity of dihydropyrimidine dehydrogenase (DPD). DPD converts endogenous uracil (U) into 5,6-dihydrouracil (UH(2) ), and analogously, 5-FU into 5-fluoro-5,6-dihydrouracil (5-FUH(2) ). Combined quantification of U and UH(2) with 5-FU and 5-FUH(2) may provide a pre-therapeutic assessment of DPD activity and further guide drug dosing during therapy. Here, we report the development of a liquid chromatography-tandem mass spectrometry assay for simultaneous quantification of U, UH(2) , 5-FU and 5-FUH(2) in human plasma. Samples were prepared by liquid-liquid extraction with 10:1 ethyl acetate-2-propanol (v/v). The evaporated samples were reconstituted in 0.1% formic acid and 10 μL aliquots were injected into the HPLC system. Analyte separation was achieved on an Atlantis dC(18) column with a mobile phase consisting of 1.0 mm ammonium acetate, 0.5 mm formic acid and 3.3% methanol. Positively ionized analytes were detected by multiple reaction monitoring. The analytical response was linear in the range 0.01-10 μm for U, 0.1-10 μm for UH(2) , 0.1-75 μm for 5-FU and 0.75-75 μm for 5-FUH(2) , covering the expected concentration ranges in plasma. The method was validated following the FDA guidelines and applied to clinical samples obtained from ten 5-FU-treated colorectal cancer patients. The present method merges the analysis of 5-FU pharmacokinetics and DPD activity into a single assay representing a valuable tool to improve the efficacy and safety of 5-FU-based chemotherapy.
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Affiliation(s)
- Barbara Büchel
- Institute of Clinical Chemistry, Inselspital, Bern University Hospital, and University of Bern, Switzerland
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16
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Analysis of severely affected patients with dihydropyrimidine dehydrogenase deficiency reveals large intragenic rearrangements of DPYD and a de novo interstitial deletion del(1)(p13.3p21.3). Hum Genet 2009; 125:581-90. [DOI: 10.1007/s00439-009-0653-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Accepted: 03/05/2009] [Indexed: 10/21/2022]
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17
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Svobaite R, Solassol I, Pinguet F, Ivanauskas L, Brès J, Bressolle FMM. HPLC with UV or mass spectrometric detection for quantifying endogenous uracil and dihydrouracil in human plasma. Clin Chem 2008; 54:1463-72. [PMID: 18635751 DOI: 10.1373/clinchem.2007.102251] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND We developed and compared 2 different methods for quantifying uracil (U) and dihydrouracil (UH(2)) in BSA and human plasma. Special attention was paid to the selectivity/specificity and the absence of a matrix effect. The UH(2)/U ratio is intended as a biomarker to identify patients with deficiency in 5-fluorouracil metabolism. METHODS We quantified U and UH(2) with 2 liquid chromatography methods after solid-phase extraction, one with UV detection (LC-UV) and the other with mass spectrometric detection (LC-MS). We selected 2 internal standards to prevent the risk of interferences. Separation was achieved with a Waters Atlantis dC18 column (LC-MS) or a Waters SymmetryShield RP18 column connected with an Atlantis dC18 (LC-UV). Mass spectrometric data were acquired in single-ion monitoring mode. RESULTS Assay imprecision in BSA solution was <15% (LC-UV) and <12% (LC-MS); in plasma, assay imprecision was <9.5% and <9.0%, respectively. Recoveries were 88.2%-110% (LC-UV) and 94.8%-107% (LC-MS). Extraction efficiencies were >or=89.0%. In BSA, the lower limits of quantification for U and UH(2) were 2.5 microg/L and 6.25 microg/L, respectively, for the LC-UV method and 2.5 microg/L and 3.1 microg/L for LC-MS. The corresponding values in plasma were 11.6 microg/L and 21.5 microg/L, and 4.1 microg/L and 12.1 microg/L. CONCLUSIONS To estimate endogenous U and UH(2) concentrations and their ratio, we recommend the use of a drug-free human plasma pool in which baseline U and UH(2) concentrations have previously been measured with the standard-addition method. Our LC-MS method, which has the better test performance and is useful for measuring UH(2)/U ratios in cancer patients, is preferred when this equipment is available.
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Affiliation(s)
- Rūta Svobaite
- Pharmacokinetic Laboratory, Faculty of Pharmacy, University Montpellier I, Montpellier, France
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18
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Yaplito-Lee J, Pitt J, Meijer J, Zoetekouw L, Meinsma R, van Kuilenburg ABP. Beta-ureidopropionase deficiency presenting with congenital anomalies of the urogenital and colorectal systems. Mol Genet Metab 2008; 93:190-4. [PMID: 17964839 DOI: 10.1016/j.ymgme.2007.09.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 09/13/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
Beta-ureidopropionase deficiency (McKusick 606673) is an autosomal recessive condition caused by mutations in the UPB1 gene. To date, five patients have been reported, including one putative case detected through newborn screening. Clinical presentation includes neurological and developmental problems. Here, we report another case of beta-ureidopropionase deficiency who presented with congenital anomalies of the urogenital and colorectal systems and with normal neurodevelopmental milestones. Analysis of a urine sample, because of the suspicion of renal stones on ultrasound, showed strongly elevated levels of the characteristic metabolites, N-carbamyl-beta-amino acids. Subsequent analysis of UPB1 identified a novel mutation 209 G>C (R70P) in exon 2 and a previously reported splice receptor mutation IVS1-2A>G. Expression studies of the R70P mutant enzyme showed that the mutant enzyme did not possess any residual activity. Long-term follow-up is required to determine the clinical significance of the beta-ureidopropionase deficiency in our patient.
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Affiliation(s)
- J Yaplito-Lee
- Metabolic Service, Genetic Health Services Victoria, Royal Children's Hospital, Melbourne, Vic. 3052, Australia.
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19
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Sparidans RW, Bosch TM, Jörger M, Schellens JHM, Beijnen JH. Liquid chromatography–tandem mass spectrometric assay for the analysis of uracil, 5,6-dihydrouracil and β-ureidopropionic acid in urine for the measurement of the activities of the pyrimidine catabolic enzymes. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 839:45-53. [PMID: 16513432 DOI: 10.1016/j.jchromb.2006.02.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Revised: 02/07/2006] [Accepted: 02/11/2006] [Indexed: 11/15/2022]
Abstract
A liquid chromatography-tandem mass spectrometric assay for the determination of uracil, 5,6-dihydrouracil and beta-ureidopropionic acid in urine was developed to measure the activities of enzymes involved in pyrimidine breakdown. The assay was required to investigate the relation between the uracil-dihydrouracil ratio and toxicities observed after treatment with fluoropyrimidines drugs. After addition of stable isotopically labelled internal standards, the analytes were isolated from a 100-microl urine sample using liquid-liquid extraction with ethyl acetate-2-propanol. Compounds were separated on an Atlantis dC18 column, using ammonium acetate-formic acid in water as the eluent. The eluate was totally led into an electrospray interface with positive ionisation and the analytes were quantified using triple quadrupole mass spectrometry. The assay was validated in the range 1.6-1600 microM, using both, artificial urine and pooled urine as matrices. Intra-day precisions were < or = 8% and inter-day precisions were < or = 10%. Accuracies between 91 and 108% were found. The analytes were chemically stable under all relevant conditions and the assay was successfully applied in two clinical studies of cancer patients treated with 5-fluorouracil or capecitabine.
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Affiliation(s)
- Rolf W Sparidans
- Utrecht University, Faculty of Science, Department of Pharmaceutical Sciences, Section of Biomedical Analysis, Division of Drug Toxicology, Sorbonnelaan 16, 3584 CA Utrecht, The Netherlands.
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20
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Hartmann S, Okun JG, Schmidt C, Langhans CD, Garbade SF, Burgard P, Haas D, Sass JO, Nyhan WL, Hoffmann GF. Comprehensive Detection of Disorders of Purine and Pyrimidine Metabolism by HPLC with Electrospray Ionization Tandem Mass Spectrometry. Clin Chem 2006; 52:1127-37. [PMID: 16613999 DOI: 10.1373/clinchem.2005.058842] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractBackground: Clinical presentation and disease severity in disorders of purine and pyrimidine metabolism vary considerably. We present a method that allows comprehensive, sensitive, and specific diagnosis of the entire spectrum of abnormalities in purine and pyrimidine metabolism in 1 analytical run.Methods: We used reversed-phase HPLC electrospray ionization tandem mass spectrometry to investigate 24 metabolites of purine and pyrimidine metabolism in urine samples from healthy persons and from patients with confirmed diagnoses of inherited metabolic disorders. Urine samples were filtered and diluted to a creatinine concentration of 0.5 mmol/L. Stable-isotope–labeled internal standards were used for quantification. The metabolites were analyzed by multiple-reaction monitoring in positive and negative ionization modes.Results: Total time of analysis was 20 min. Recovery (n = 8) of a compound after addition of a known concentration was 85%–133%. The mean intraday variation (n = 10) was 12%. The interday variation (n = 7) was ≤17%. Age-related reference intervals were established for each compound. Analysis of patient urine samples revealed major differences in tandem mass spectrometry profiles compared with those of control samples. Twelve deficiencies were reliably detected: hypoxanthine guanine phosphoribosyl transferase, xanthine dehydrogenase, purine nucleoside phosphorylase, adenylosuccinate lyase, uridine monophosphate synthase, adenosine deaminase, adenine phosphoribosyl transferase, molybdenum cofactor, thymidine phosphorylase, dihydropyrimidine dehydrogenase, dihydropyrimidinase, and β-ureidopropionase.Conclusion: This method enables reliable detection of 13 defects in purine and pyrimidine metabolism in a single analytical run.
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Affiliation(s)
- Susen Hartmann
- Division of Metabolic Diseases, Department of General Pediatrics, University Children's Hospital Heidelberg, Heidelberg, Germany.
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Assmann BE, Van Kuilenburg ABP, Distelmaier F, Abeling NGGM, Rosenbaum T, Schaper J, Duran M, Mayatepek E. beta-Ureidopropionase Deficiency Presenting with Febrile Status Epilepticus. Epilepsia 2006; 47:215-7. [PMID: 16417553 DOI: 10.1111/j.1528-1167.2006.00391.x] [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] [Indexed: 11/29/2022]
Abstract
UNLABELLED Beta-ureidopropionase is the third enzyme in the catabolic pathway of uracil and thymine. To date, only three other patients are reported with this inborn error of metabolism. We report the clinical presentation of a male patient who presented at the age of 4 months after an ALTE-like event (ALTE = acute life-threatening event) with febrile status epilepticus. Such a clinical presentation has not been reported before in this condition. Diagnosis was based on biochemical, enzymatic and molecular studies. MRI (magnetic resonance imaging) at the age of 11 months demonstrated large subdural hematomata and global supratentorial atrophy. At that time the patient showed severe psychomotor retardation with muscular hypotonia, extremely limited visual contact and poorly controlled epilepsy. CONCLUSIONS Pyrimidine degradation defects should be included in the differential diagnosis of convulsions, (febrile) status epilepticus, psychomotor retardation and possibly also ALTE-like events.
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van Kuilenburg ABP, Meinsma R, Beke E, Assmann B, Ribes A, Lorente I, Busch R, Mayatepek E, Abeling NGGM, van Cruchten A, Stroomer AEM, van Lenthe H, Zoetekouw L, Kulik W, Hoffmann GF, Voit T, Wevers RA, Rutsch F, van Gennip AH. β-Ureidopropionase deficiency: an inborn error of pyrimidine degradation associated with neurological abnormalities. Hum Mol Genet 2004; 13:2793-801. [PMID: 15385443 DOI: 10.1093/hmg/ddh303] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
beta-Ureidopropionase deficiency is an inborn error of the pyrimidine degradation pathway, affecting the cleavage of N-carbamyl-beta-alanine and N-carbamyl-beta-aminoisobutyric acid. In this study, we report the elucidation of the genetic basis underlying a beta-ureidopropionase deficiency in four patients presenting with neurological abnormalities and strongly elevated levels of N-carbamyl-beta-alanine and N-carbamyl-beta-aminoisobutyric acid in plasma, cerebrospinal fluid and urine. No beta-ureidopropionase activity could be detected in a liver biopsy obtained from one of the patients, which reflected the complete absence of the beta-ureidopropionase protein. Analysis of the beta-ureidopropionase gene (UPB1) of these patients revealed the presence of two splice-site mutations (IVS1-2A>G and IVS8-1G>A) and one missense mutation (A85E). Heterologous expression of the mutant enzyme in Escherichia coli showed that the A85E mutation resulted in a mutant beta-ureidopropionase enzyme without residual activity. Our results demonstrate that the N-carbamyl-beta-amino aciduria in these patients is due to a deficiency of beta-ureidopropionase, which is caused by mutations in the UPB1 gene. Furthermore, an altered homeostasis of beta-aminoisobutyric acid and/or increased oxidative stress might contribute to some of the clinical abnormalities encountered in patients with a beta-ureidopropionase deficiency. An analysis of the presence of the two splice site mutations and the missense mutation in 95 controls identified one individual who proved to be heterozygous for the IVS8-1G>A mutation. Thus, a beta-ureidopropionase deficiency might not be as rare as is generally considered.
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