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Sen K, Izem R, Long Y, Jiang J, Konczal LL, McCarter RJ, Gropman AL, Bedoyan JK. Are asymptomatic carriers of OTC deficiency always asymptomatic? A multicentric retrospective study of risk using the UCDC longitudinal study database. Mol Genet Genomic Med 2024; 12:e2443. [PMID: 38634223 PMCID: PMC11024633 DOI: 10.1002/mgg3.2443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 03/24/2024] [Accepted: 04/02/2024] [Indexed: 04/19/2024] Open
Abstract
BACKGROUND Ornithine transcarbamylase deficiency (OTCD) due to an X-linked OTC mutation, is responsible for moderate to severe hyperammonemia (HA) with substantial morbidity and mortality. About 80% of females with OTCD remain apparently "asymptomatic" with limited studies of their clinical characteristics and long-term health vulnerabilities. Multimodal neuroimaging studies and executive function testing have shown that asymptomatic females exhibit limitations when stressed to perform at higher cognitive load and had reduced activation of the prefrontal cortex. This retrospective study aims to improve understanding of factors that might predict development of defined complications and serious illness in apparent asymptomatic females. A proband and her daughter are presented to highlight the utility of multimodal neuroimaging studies and to underscore that asymptomatic females with OTCD are not always asymptomatic. METHODS We review data from 302 heterozygote females with OTCD enrolled in the Urea Cycle Disorders Consortium (UCDC) longitudinal natural history database. We apply multiple neuroimaging modalities in the workup of a proband and her daughter. RESULTS Among the females in the database, 143 were noted as symptomatic at baseline (Sym). We focused on females who were asymptomatic (Asx, n = 111) and those who were asymptomatic initially upon enrollment in study but who later became symptomatic sometime during follow-up (Asx/Sym, n = 22). The majority of Asx (86%) and Asx/Sym (75%) subjects did not restrict protein at baseline, and ~38% of Asx and 33% of Asx/Sym subjects suffered from mild to severe neuropsychiatric conditions such as mood disorder and sleep problems. The risk of mild to severe HA sometime later in life for the Asx and Asx/Sym subjects as a combined group was ~4% (5/133), with ammonia ranging from 77 to 470 μM and at least half (2/4) of subjects requiring hospital admission and nitrogen scavenger therapy. For this combined group, the median age of first HA crisis was 50 years, whereas the median age of first symptom which included neuropsychiatric and/or behavioral symptoms was 17 years. The multimodal neuroimaging studies in female heterozygotes with OTCD also underscore that asymptomatic female heterozygotes with OTCD (e.g., proband) are not always asymptomatic. CONCLUSIONS Analysis of Asx and Asx/Sym females with OTCD in this study suggests that future evidence-based management guidelines and/or a clinical risk score calculator for this cohort could be useful management tools to reduce morbidity and improve long-term quality of life.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Neurodevelopmental PediatricsChildren's National Hospital, The George Washington School of MedicineWashingtonDCUSA
| | - Rima Izem
- Center for Translational Sciences, Children's National HospitalThe George Washington UniversityWashingtonDCUSA
- Children's National HospitalWashingtonDCUSA
| | - Yuelin Long
- Columbia University Mailman School of Public HealthNew YorkNew YorkUSA
| | - Jiji Jiang
- Center for Translational Sciences, Children's National HospitalThe George Washington UniversityWashingtonDCUSA
- Children's National HospitalWashingtonDCUSA
| | - Laura L. Konczal
- Center for Human Genetics, University Hospitals Cleveland Medical Center, Department of Genetics and Genome SciencesCase Western Reserve University School of MedicineClevelandOhioUSA
| | - Robert J. McCarter
- Center for Translational Sciences, Children's National HospitalThe George Washington UniversityWashingtonDCUSA
- Children's National HospitalWashingtonDCUSA
| | - Andrea L. Gropman
- Division of Neurogenetics and Neurodevelopmental PediatricsChildren's National Hospital, The George Washington School of MedicineWashingtonDCUSA
- Center for Translational Sciences, Children's National HospitalThe George Washington UniversityWashingtonDCUSA
| | - Jirair K. Bedoyan
- Division of Genetic and Genomic Medicine, Department of PediatricsUPMC Children's Hospital of Pittsburgh, University of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
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Ramosaj A, Singhal P, Schaller A, Laemmle A. Induced pluripotent stem cell technology as diagnostic tool in patients with suspected ornithine transcarbamylase deficiency lacking genetic confirmation. Mol Genet Metab Rep 2023; 37:101007. [PMID: 38053928 PMCID: PMC10694731 DOI: 10.1016/j.ymgmr.2023.101007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 12/07/2023] Open
Abstract
Ornithine transcarbamylase (OTC) deficiency (OTCD) is an X-linked urea cycle disorder. In females - undergoing random X chromosomal inactivation (XCI) - disease severity depends on the XCI pattern. Hence, female OTCD subjects with favorable XCI display normal OTC expression and activity and are healthy carriers. Whereas females undergoing less favorable XCI may suffer from severe and fatal OTCD. In approximately 20% of patients with biochemical evidence of OTCD, no mutation can be identified hampering definitive diagnosis and adequate treatment.Here, we describe a female patient with high suspicion of OTCD in whom molecular genetic work-up did not reveal pathogenic variants in the OTC gene. In her case, this was particularly challenging, since she was awaiting liver transplantation due to metabolic instability. In order to substantiate the suspected diagnosis of OTCD, we applied our previously reported in vitro OTCD liver disease model. Patient-derived skin fibroblasts were reprogrammed into human induced pluripotent stem cells (hiPSCs) followed by differentiation into hepatocytes (hiPSC-Heps). Among five randomly selected hiPSC clones - differentiated into hiPSC-Heps - one clone expressed OTC protein, while the four remaining clones lacked OTC expression, supporting the patient's suspected diagnosis of OTCD.To conclude, we demonstrate that hiPSC technology is a powerful diagnostic tool to substantiate the suspected diagnosis of OTCD in patients lacking genetic confirmation. Furthermore, selecting clones that exclusively express the wild-type OTC protein, could be used strategically as cellular therapy in future. Ultimately, this approach might be applicable to virtually any X-linked disease. Synopsis Induced pluripotent stem cell technology is a powerful diagnostic tool to substantiate the suspected diagnosis of OTCD in patients lacking genetic confirmation.
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Affiliation(s)
- Adhuresa Ramosaj
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Palak Singhal
- Department of Human Genetics, Inselspital, Bern University Hospital, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - André Schaller
- Department of Human Genetics, Inselspital, Bern University Hospital, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Alexander Laemmle
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Yamazaki K, Kubara K, Ishii S, Kondo K, Suzuki Y, Miyazaki T, Mitsuhashi K, Ito M, Tsukahara K. Lipid nanoparticle-targeted mRNA formulation as a treatment for ornithine-transcarbamylase deficiency model mice. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 33:210-226. [PMID: 37520683 PMCID: PMC10372164 DOI: 10.1016/j.omtn.2023.06.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/28/2023] [Indexed: 08/01/2023]
Abstract
Ornithine transcarbamylase (OTC) plays a significant role in the urea cycle, a metabolic pathway functioning in the liver to detoxify ammonia. OTC deficiency (OTCD) is the most prevalent urea cycle disorder. Here, we show that intravenously delivered human OTC (hOTC) mRNA by lipid nanoparticles (LNP) was an effective treatment for OTCD by restoring the urea cycle. We observed a homotrimer conformation of hOTC proteins produced by the mRNA-LNP in cells by cryo-electron microscopy. The immunohistochemistry revealed the mitochondria localization of produced hOTC proteins in hepatocytes in mice. In livers of mice intravenously injected with hOTC-mRNA/LNP at 1.0 mg/kg, the delivered hOTC mRNA levels steeply decreased with a half-life (t1/2) of 7.1 h, whereas the produced hOTC protein levels retained for 5 days and then declined with a t1/2 of 2.2 days. In OTCD model mice (high-protein diet-fed Otcspf-ash hemizygous males), a single dose of hOTC-mRNA/LNP at 3.0 mg/kg ameliorated hyperammonemia and weight loss with prolonged survival rate (22 days) compared with that of untreated mice (11 days). Weekly repeated doses at 0.3 and 1.0 mg/kg were well tolerated in wild-type mice and showed a dose-dependent amelioration of survival rate in OTCD mice, thus, showing the therapeutic potential of LNP-formulated hOTC mRNA for OTCD.
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Affiliation(s)
- Kazuto Yamazaki
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Kenji Kubara
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Satoko Ishii
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Keita Kondo
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Yuta Suzuki
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Takayuki Miyazaki
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Kaoru Mitsuhashi
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Masashi Ito
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
| | - Kappei Tsukahara
- Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan
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Baba C, Yukimasa S, Yasuno R, Ichiyanagi H, Ninagawa J, Kasuya S, Kasahara M, Horikawa R, Nagasaka Y, Suzuki Y. Anesthesia management protocol for liver transplantation as treatment for ornithine transcarbamylase deficiency. Paediatr Anaesth 2023; 33:620-630. [PMID: 37401903 DOI: 10.1111/pan.14691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 04/18/2023] [Accepted: 04/20/2023] [Indexed: 07/05/2023]
Abstract
BACKGROUND Ornithine transcarbamylase deficiency is an X-linked genetic disorder that induces accumulation of ammonia in the liver and is the most common urea cycle disorder. The clinical manifestation of ornithine transcarbamylase deficiency is hyperammonemia that causes irreversible neurological damage. Liver transplantation is a curative therapy for ornithine transcarbamylase deficiency. The aim of this study is to suggest, from our previous experience, an anesthesia management protocol of liver transplantation for ornithine transcarbamylase deficiency, particularly focused on liver transplantation for cases with uncontrolled hyperammonemia. METHOD We retrospectively reviewed our anesthesia-related experience in all cases of liver transplantation for ornithine transcarbamylase deficiency in our center. RESULTS Twenty-nine liver transplantation cases for ornithine transcarbamylase deficiency were found between November 2005 and March 2021 in our center. Of these, 25 cases were stable through the perioperative period. However, 2 cases with carrier donor graft had hyperammonemia after liver transplantation. Another two cases had uncontrolled hyperammonemia before liver transplantation, even with continuous hemodialysis. They underwent life-saving liver transplantation. Their metabolic status stabilized after the anhepatic phase. CONCLUSION Liver transplantation for cases with uncontrolled hyperammonemia can be performed with proper management. Second, liver transplantation with carrier donors should be avoided because of the risk of postoperative recurrence.
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Affiliation(s)
- Chiaki Baba
- Division of Anesthesia, Department of Critical Care and Anesthesia, National Center for Child Health and Development, Tokyo, Japan
| | - Sho Yukimasa
- Division of Anesthesia, Department of Critical Care and Anesthesia, National Center for Child Health and Development, Tokyo, Japan
| | - Risa Yasuno
- Department of Anesthesiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Hiroki Ichiyanagi
- Division of Anesthesia, Department of Critical Care and Anesthesia, National Center for Child Health and Development, Tokyo, Japan
| | - Jun Ninagawa
- Division of Anesthesia, Department of Critical Care and Anesthesia, National Center for Child Health and Development, Tokyo, Japan
| | - Shugo Kasuya
- Division of Anesthesia, Department of Critical Care and Anesthesia, National Center for Child Health and Development, Tokyo, Japan
| | - Mureo Kasahara
- Center for Organ Transplantation, National Center for Child Health and Development, Tokyo, Japan
| | - Reiko Horikawa
- Division of Endocrinology and Metabolism, National Center for Child Health and Development, Tokyo, Japan
| | - Yasuko Nagasaka
- Department of Anesthesiology, Tokyo Women's Medical University, Tokyo, Japan
| | - Yasuyuki Suzuki
- Division of Anesthesia, Department of Critical Care and Anesthesia, National Center for Child Health and Development, Tokyo, Japan
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Lo RS, Cromie GA, Tang M, Teng K, Owens K, Sirr A, Kutz JN, Morizono H, Caldovic L, Ah Mew N, Gropman A, Dudley AM. The functional impact of 1,570 individual amino acid substitutions in human OTC. Am J Hum Genet 2023; 110:863-879. [PMID: 37146589 PMCID: PMC10183466 DOI: 10.1016/j.ajhg.2023.03.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/30/2023] [Indexed: 05/07/2023] Open
Abstract
Deleterious mutations in the X-linked gene encoding ornithine transcarbamylase (OTC) cause the most common urea cycle disorder, OTC deficiency. This rare but highly actionable disease can present with severe neonatal onset in males or with later onset in either sex. Individuals with neonatal onset appear normal at birth but rapidly develop hyperammonemia, which can progress to cerebral edema, coma, and death, outcomes ameliorated by rapid diagnosis and treatment. Here, we develop a high-throughput functional assay for human OTC and individually measure the impact of 1,570 variants, 84% of all SNV-accessible missense mutations. Comparison to existing clinical significance calls, demonstrated that our assay distinguishes known benign from pathogenic variants and variants with neonatal onset from late-onset disease presentation. This functional stratification allowed us to identify score ranges corresponding to clinically relevant levels of impairment of OTC activity. Examining the results of our assay in the context of protein structure further allowed us to identify a 13 amino acid domain, the SMG loop, whose function appears to be required in human cells but not in yeast. Finally, inclusion of our data as PS3 evidence under the current ACMG guidelines, in a pilot reclassification of 34 variants with complete loss of activity, would change the classification of 22 from variants of unknown significance to clinically actionable likely pathogenic variants. These results illustrate how large-scale functional assays are especially powerful when applied to rare genetic diseases.
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Affiliation(s)
- Russell S Lo
- Pacific Northwest Research Institute, Seattle, WA, USA
| | | | - Michelle Tang
- Pacific Northwest Research Institute, Seattle, WA, USA
| | - Kevin Teng
- Pacific Northwest Research Institute, Seattle, WA, USA
| | - Katherine Owens
- Pacific Northwest Research Institute, Seattle, WA, USA; Department of Applied Mathematics, University of Washington, Seattle, WA, USA
| | - Amy Sirr
- Pacific Northwest Research Institute, Seattle, WA, USA
| | - J Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, WA, USA
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Nicholas Ah Mew
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA
| | - Andrea Gropman
- Center for Genetic Medicine Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA; Department of Genomics and Precision Medicine, School of Medicine and Health Sciences, The George Washington University, Washington, DC, USA; Department of Neurology, Division of Neurogenetics and Neurodevelopmental Disabilities, Children's National Hospital, Washington, DC, USA; Center for Neuroscience Research, Children's National Research Institute, Children's National Hospital, Washington, DC, USA
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Feigenbaum A, Lamale-Smith L, Weinstein L. Considerations for prenatal and postpartum management of a female patient with ornithine transcarbamylase deficiency. Mol Genet Metab Rep 2022; 33:100894. [PMID: 36620386 PMCID: PMC9817480 DOI: 10.1016/j.ymgmr.2022.100894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/27/2022] [Accepted: 06/27/2022] [Indexed: 01/11/2023] Open
Abstract
We report on pregnancy management and outcomes in a 27-year-old female patient with ornithine transcarbamylase (OTC) deficiency, the most common inherited enzyme deficiency in the urea cycle. Our patient was diagnosed during childhood after hyperammonemia associated with surgery and steroid treatment and was well-controlled with nitrogen scavenger treatment, low-protein diet, and L-citrulline supplementation. OTC gene sequencing identified a variant of unknown significance that has more recently been classified as likely pathogenic. Women with OTC deficiency are at increased risk of hyperammonemia during pregnancy and the postpartum period, therefore monthly follow up and laboratory assessments are critical in management decision making. Our patient was maintained on glycerol phenylbutyrate, L-citrulline and essential amino acid supplements, along with restricted protein intake during pregnancy. A multidisciplinary approach with the obstetrics, prenatal genetics, high risk obstetric, and anesthesia teams was also necessary for optimal management during pregnancy, throughout labor and delivery, and during the postpartum period. After successful childbirth and discharge, our patient experienced a hyperammonemic crisis related to poor enteral nutrition, and acute management protocols were implemented to stabilize her. For her newborn son, acute hyperammonemia protocols were on standby, and newborn screening and laboratory testing were expedited to assess his risk. He was healthy and did not experience symptoms of concern. In this case report, we emphasize the importance of close collaboration with maternal-fetal medicine team members during and immediately after pregnancy to ensure successful management of a female patient with OTC deficiency and her newborn.
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Key Words
- BCAA, branched-chain amino acids
- BID, twice daily
- D10, 10% dextrose
- EAA, essential amino acids
- GPB, glycerol phenylbutyrate
- IV, intravenous
- NICU, neonatal intensive care unit
- OTC, ornithine transcarbamylase
- Ornithine transcarbamylase deficiency
- PICC, peripherally inserted central catheter
- PO, per os/orally
- Peripartum management
- Pregnancy
- TID, three times daily
- UCD, urea cycle disorder
- Urea cycle disorder
- X-linked, hyperammonemia
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Affiliation(s)
- Annette Feigenbaum
- Department of Pediatrics and Biochemical Genetics, Rady Children's Hospital-San Diego, University of California San Diego, 3020 Children's Way #5031, San Diego, CA 92123, USA
- Corresponding author at: 3020 Children's Way #5031, San Diego, CA 92123, USA.
| | - Leah Lamale-Smith
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California San Diego, 9300 Campus Point Drive, #7433, San Diego, CA 92037, USA
| | - Lawrence Weinstein
- Department of Anesthesiology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Han ST, Anderson KJ, Bjornsson HT, Longo N, Valle D. A promoter variant in the OTC gene associated with late and variable age of onset hyperammonemia. J Inherit Metab Dis 2022; 45:710-718. [PMID: 35605046 DOI: 10.1002/jimd.12524] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/12/2022] [Accepted: 05/20/2022] [Indexed: 11/11/2022]
Abstract
Ornithine transcarbamylase deficiency (OTCD) is an X-linked inborn error caused by loss of function variants in the OTC gene typically associated with severe neonatal hyperammonemia. Rare examples of late-onset OTCD have also been described. Here, we describe an OTC promoter variant, c.-106C>A, in a conserved HNF4a binding site, identified in two male siblings in Family 1 whose first and only recognized episodes of severe hyperammonemia occurred at ages 14 and 39 years, respectively. We identified the same OTC variant segregating in a large family with late-onset OTCD with variable expressivity (Family 2). We show that this OTC promoter variant reduces expression >5-fold in a dual-luciferase assay that tests promoter function. Addition of an upstream OTC enhancer increases expression of both the wild type and the c.-106C>A variant promoter constructs >5-fold with the mutant promoter still about fourfold lower than the wild type. Thus, in both contexts, the promoter variant results in substantially lower OTC expression. Under normal demand on urea cycle function, OTC expression in hemizygous males, although reduced, is sufficient to meet the demand for waste nitrogen excretion. However, in response to severe metabolic stress with attendant increased requirements on urea cycle function, the impaired promoter function results in inadequate OTC expression with resultant hyperammonemia. In the absence of precipitating events, hemizygotes with this allele are asymptomatic, explaining the late age of onset of hyperammonemia in affected individuals and the incomplete penetrance observed in some individuals in Family 2.
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Affiliation(s)
- Sangwoo T Han
- Predoctoral Training Program in Human Genetics, McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Katherine J Anderson
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Hans T Bjornsson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
- Landspitali University Hospital, Reykjavik, Iceland
| | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - David Valle
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Baruteau J, Cunningham SC, Yilmaz BS, Perocheau DP, Eaglestone S, Burke D, Thrasher AJ, Waddington SN, Lisowski L, Alexander IE, Gissen P. Safety and efficacy of an engineered hepatotropic AAV gene therapy for ornithine transcarbamylase deficiency in cynomolgus monkeys. Mol Ther Methods Clin Dev 2021; 23:135-146. [PMID: 34703837 PMCID: PMC8517016 DOI: 10.1016/j.omtm.2021.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/08/2021] [Indexed: 12/31/2022]
Abstract
X-linked inherited ornithine transcarbamylase deficiency (OTCD) is the most common disorder affecting the liver-based urea cycle, a pathway enabling detoxification of nitrogen waste and endogenous arginine biosynthesis. Patients develop acute hyperammonemia leading to neurological sequelae or death despite the best-accepted therapy based on ammonia scavengers and protein-restricted diet. Liver transplantation is curative but associated with procedure-related complications and lifelong immunosuppression. Adeno-associated viral (AAV) vectors have demonstrated safety and clinical benefits in a rapidly growing number of clinical trials for inherited metabolic liver diseases. Engineered AAV capsids have shown promising enhanced liver tropism. Here, we conducted a good-laboratory practice-compliant investigational new drug-enabling study to assess the safety of intravenous liver-tropic AAVLK03 gene transfer of a human codon-optimized OTC gene. Juvenile cynomolgus monkeys received vehicle and a low and high dose of vector (2 × 1012 and 2 × 1013 vector genome (vg)/kg, respectively) and were monitored for 26 weeks for in-life safety with sequential liver biopsies at 1 and 13 weeks post-vector administration. Upon completion of monitoring, animals were euthanized to study vector biodistribution, immune responses, and histopathology. The product was well tolerated with no adverse clinical events, predominant hepatic biodistribution, and sustained supra-physiological OTC overexpression. This study supports the clinical deployment of intravenous AAVLK03 for severe OTCD.
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Affiliation(s)
- Julien Baruteau
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
- National Institute of Health Research, Great Ormond Street Biomedical Research Centre, London WC1N 1EH, UK
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Sharon C. Cunningham
- Gene Therapy Research Unit, Children’s Medical Research Institute and Children’s Hospital at Westmead, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
| | - Berna Seker Yilmaz
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
- Department of Pediatric Metabolic Medicine, Mersin University, Mersin 33110, Turkey
| | - Dany P. Perocheau
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Simon Eaglestone
- Translational Research Office, University College London, London, UK
| | - Derek Burke
- Enzyme Unit, NIHR BRC, Great Ormond Street Hospital Foundation Trust and UCL Great Ormond Street Institute of Child Health, London, UK
| | - Adrian J. Thrasher
- Molecular & Cellular Immunology, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Simon N. Waddington
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, 86-96 Chenies Mews, London, UK
- MRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witswatersrand, Johannesburg, South Africa
| | - Leszek Lisowski
- Translational Vectorology Unit, Children’s Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
- Military Institute of Medicine, Laboratory of Molecular Oncology and Innovative Therapies, Warsaw, Poland
| | - Ian E. Alexander
- Gene Therapy Research Unit, Children’s Medical Research Institute and Children’s Hospital at Westmead, Faculty of Medicine and Health, The University of Sydney, Sydney, Australia
- Discipline of Child and Adolescent Health, Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Westmead, NSW 2145, Australia
| | - Paul Gissen
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
- National Institute of Health Research, Great Ormond Street Biomedical Research Centre, London WC1N 1EH, UK
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
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Gitto L, Fuller CE, Calleo VJ, Tawil M, Thach R, Revercomb C. Late-onset of ornithine transcarbamylase deficiency: A rare medical examiner case. J Forensic Sci 2021; 67:813-819. [PMID: 34726276 DOI: 10.1111/1556-4029.14934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 11/26/2022]
Abstract
Ornithine Transcarbamylase (OTC) is an enzyme of the urea cycle, which converts ammonia into urea in the liver cells. OTC plays a crucial role in the breakdown and removal of nitrogen in the body. OTC deficiency is a rare X-linked recessive disorder that classically presents in early life with signs of hyperammonemia and progressive central nervous system involvement resulting in seizures, coma, and death. Sentinel presentation in adulthood is quite rare. A 29-year-old man developed altered mental status after receiving an epidural steroid injection 3 days earlier for back pain. He presented to the emergency department severely agitated, and his workup revealed an elevated ammonia level of 125 µmol/L. He refused admission and was discharged against medical advice. The following day, his mentation deteriorated, he developed status epilepticus, and was transported to another emergency department. He was admitted with worsening hyperammonemia (levels rising to over 700 µmol/L). His clinical condition progressive deteriorated, and he developed encephalopathy and diffuse cerebral edema. Liver function testing indicated progressive liver damage, and amino acids were detected in his blood and urine. Clinical and laboratory findings suggested undiagnosed OTC enzyme deficiency. He died 2 days after admission. An autopsy showed an 1890 g liver with diffuse yellow discoloration and softening. Histology and electron microscopy revealed findings suggestive of urea cycle disorder, such as microvesicular steatosis, apoptosis, and scattered mitosis, clusters of clear hepatocytes at the PAS stain, and mitochondria abnormalities. Genetic analysis revealed a hemizygous pathogenic variant of the OTC gene (c.622G>A). OTC deficiency should be suspected in subjects with hyperammonemic encephalopathy. If a genetic mutation is identified in the deceased, surviving family members should be screened to prevent potential life-threatening complications.
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Affiliation(s)
- Lorenzo Gitto
- Department of Pathology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Cristine E Fuller
- Department of Pathology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Vincent J Calleo
- Upstate New York Poison Center, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Michel Tawil
- Department of Pathology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Rasmey Thach
- Department of Medicine, William Beaumont Army Medical Center, Fort Bliss, Texas, USA
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10
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Couchet M, Breuillard C, Corne C, Rendu J, Morio B, Schlattner U, Moinard C. Ornithine Transcarbamylase - From Structure to Metabolism: An Update. Front Physiol 2021; 12:748249. [PMID: 34658931 PMCID: PMC8517447 DOI: 10.3389/fphys.2021.748249] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/07/2021] [Indexed: 12/30/2022] Open
Abstract
Ornithine transcarbamylase (OTC; EC 2.1.3.3) is a ubiquitous enzyme found in almost all organisms, including vertebrates, microorganisms, and plants. Anabolic, mostly trimeric OTCs catalyze the production of L-citrulline from L-ornithine which is a part of the urea cycle. In eukaryotes, such OTC localizes to the mitochondrial matrix, partially bound to the mitochondrial inner membrane and part of channeling multi-enzyme assemblies. In mammals, mainly two organs express OTC: the liver, where it is an integral part of the urea cycle, and the intestine, where it synthesizes citrulline for export and plays a major role in amino acid homeostasis, particularly of L-glutamine and L-arginine. Here, we give an overview on OTC genes and proteins, their tissue distribution, regulation, and physiological function, emphasizing the importance of OTC and urea cycle enzymes for metabolic regulation in human health and disease. Finally, we summarize the current knowledge of OTC deficiency, a rare X-linked human genetic disorder, and its emerging role in various chronic pathologies.
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Affiliation(s)
- Morgane Couchet
- Université Grenoble Alpes, Inserm U1055, Laboratory of Fundamental and Applied Bioenergetics, Grenoble, France
| | - Charlotte Breuillard
- Université Grenoble Alpes, Inserm U1055, Laboratory of Fundamental and Applied Bioenergetics, Grenoble, France
| | | | - John Rendu
- Centre Hospitalier Université Grenoble Alpes, Grenoble, France
| | - Béatrice Morio
- CarMeN Laboratory, INSERM U1060, INRAE U1397, Lyon, France
| | - Uwe Schlattner
- Université Grenoble Alpes, Inserm U1055, Laboratory of Fundamental and Applied Bioenergetics, Grenoble, France.,Institut Universitaire de France, Paris, France
| | - Christophe Moinard
- Université Grenoble Alpes, Inserm U1055, Laboratory of Fundamental and Applied Bioenergetics, Grenoble, France
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11
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Gobin-Limballe S, Ottolenghi C, Reyal F, Arnoux JB, Magen M, Simon M, Brassier A, Jabot-Hanin F, Lonlay PD, Pontoizeau C, Guirat M, Rio M, Gesny R, Gigarel N, Royer G, Steffann J, Munnich A, Bonnefont JP. OTC deficiency in females: Phenotype-genotype correlation based on a 130-family cohort. J Inherit Metab Dis 2021; 44:1235-1247. [PMID: 34014569 DOI: 10.1002/jimd.12404] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 12/30/2022]
Abstract
OTC deficiency, an inherited urea cycle disorder, is caused by mutations in the X-linked OTC gene. Phenotype-genotype correlations are well understood in males but still poorly known in females. Taking advantage of a cohort of 130 families (289 females), we assessed the relative contribution of OTC enzyme activity, X chromosome inactivation, and OTC gene sequencing to genetic counseling in heterozygous females. Twenty two percent of the heterozygous females were clinically affected, with episodic (11%), chronic (7.5%), or neonatal forms of the disease (3.5%). Overall mortality rate was 4%. OTC activity, ranging from 0% to 60%, did not correlate with phenotype at the individual level. Analysis of multiple samples from 4 mutant livers showed intra-hepatic variability of OTC activity and X inactivation profile (range of variability: 30% and 20%, respectively) without correlation between both parameters for 3 of the 4 livers. Ninety disease-causing variants were found, 27 of which were novel. Mutations were classified as "mild" or "severe," based on male phenotypes and/or in silico prediction. In our cohort, a serious disease occurred in 32% of females with a severe mutation, compared to 4% in females with a mild mutation (odds ratio = 1.365; P = 1.6e-06). These data should help prenatal diagnosis for heterozygous females and genetic counseling after fortuitous findings of OTC variants in pangenomic sequencing.
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Affiliation(s)
| | - Chris Ottolenghi
- Metabolomic and Proteomic Biochemistry Department, Necker Hospital, APHP Centre- Paris University, Paris, France
- INSERM UMR1163, Institut Imagine, Paris University, Paris, France
| | - Fabien Reyal
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
- Breast Gynecologic Cancer Reconstructive Team, Institut Curie, Paris University, Paris, France
| | - Jean-Baptiste Arnoux
- Inherited Metabolic Disease Department and National Reference Centre for Inherited Metabolic diseases, Necker Hospital, APHP Centre-Paris University, Paris, France
- INSERM U1151, INEM, Paris University, Paris, France
| | - Maryse Magen
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Marie Simon
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Anaïs Brassier
- Inherited Metabolic Disease Department and National Reference Centre for Inherited Metabolic diseases, Necker Hospital, APHP Centre-Paris University, Paris, France
- INSERM U1151, INEM, Paris University, Paris, France
| | - Fabienne Jabot-Hanin
- Bioinformatics Platform, Paris University, INSERM UMR1163, Institut Imagine, Paris, France
- Structure Federative de Recherche Necker, INSERM US24/CNRS UMS3633, Paris, France
| | - Pascale De Lonlay
- Inherited Metabolic Disease Department and National Reference Centre for Inherited Metabolic diseases, Necker Hospital, APHP Centre-Paris University, Paris, France
- INSERM U1151, INEM, Paris University, Paris, France
| | - Clement Pontoizeau
- Metabolomic and Proteomic Biochemistry Department, Necker Hospital, APHP Centre- Paris University, Paris, France
- INSERM UMR1163, Institut Imagine, Paris University, Paris, France
| | - Manel Guirat
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Marlene Rio
- Clinical Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Roselyne Gesny
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Nadine Gigarel
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Ghislaine Royer
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Julie Steffann
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
- INSERM UMR1163, Institut Imagine, Paris University, Paris, France
| | - Arnold Munnich
- INSERM UMR1163, Institut Imagine, Paris University, Paris, France
- Clinical Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
| | - Jean-Paul Bonnefont
- Molecular Genetics Department, Necker Hospital, APHP Centre-Paris University, Paris, France
- INSERM UMR1163, Institut Imagine, Paris University, Paris, France
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12
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Bernal AC, Tubio MC, Crespo C, Eiroa HD. Clinical and Genetic Characterization and Biochemical Correlation at Presentation in 48 Patients Diagnosed with Urea Cycle Disorders at the Hospital Juan P Garrahan, Argentina. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2021. [DOI: 10.1590/2326-4594-jiems-2020-0026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
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13
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The Application of Next-Generation Sequencing (NGS) in Neonatal-Onset Urea Cycle Disorders (UCDs): Clinical Course, Metabolomic Profiling, and Genetic Findings in Nine Chinese Hyperammonemia Patients. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5690915. [PMID: 32934962 PMCID: PMC7479453 DOI: 10.1155/2020/5690915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022]
Abstract
During Jan. 2016–Dec. 2019, nine Chinese patients from eight unrelated families were diagnosed with neonatal-onset UCDs by targeted panel sequencing or whole-exome sequencing (WES). Their clinical manifestations, biochemical features, 180-day-age outcomes, and molecular genetic characteristics were reviewed retrospectively. NGS-based tests revealed 7 patients diagnosed with ornithine transcarbamylase deficiency (OTCD) and 2 with carbamoylphosphate synthetase I deficiency (CPS1D). The spectrum of the clinical presentation of nine affected individuals progressed from unspecific symptoms like poor feeding to somnolence, coma, and death. All patients presented with an acute hyperammonemia. The most robust metabolic pattern in OTCD was hyperglutaminemic hyperammonemia with high concentration of urine orotic acid, and it was reported in six patients. Of ten variants found on the OTC gene and CPS1 gene, 3 were novel: (c.176T>C (p.L59P)) in the OTC gene, c.2938G>A (p.G980S) and c.3734T>A (p.L1245H) in the CPS1 gene. There was a high mortality rate of 77.78% (7/9) for all the defects combined. An OTC-deficient male and a CPS1-deficient female survived from episodes of hyperammonemia. Although prompt recognition of UCD and the use of alternative pathway therapy in addition to provision of appropriate nutrition and dialysis improved survival, the overall outcomes for the neonatal-onset type are poor in China.
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14
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Ducich N, Ah Mew N, Bedoyan JK. The E273del variant of uncertain significance of the ornithine transcarbamylase gene - a case for reclassification. Mol Genet Metab Rep 2020; 23:100598. [PMID: 32420033 PMCID: PMC7218070 DOI: 10.1016/j.ymgmr.2020.100598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/28/2020] [Indexed: 11/26/2022] Open
Affiliation(s)
- Nicole Ducich
- School of Medicine, Case Western Reserve University (CWRU), Cleveland, OH, USA
| | - Nicholas Ah Mew
- Children's National Rare Disease Institute, The George Washington University, Washington, DC, USA
| | - Jirair K Bedoyan
- Department of Genetics and Genome Sciences, CWRU, Cleveland, OH, USA.,Department of Pediatrics, CWRU, Cleveland, OH, USA.,Center for Human Genetics, University Hospitals Cleveland Medical Center (UHCMC), Cleveland, OH, USA.,Center for Inherited Disorders of Energy Metabolism, UHCMC, Cleveland, OH, USA
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15
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Zheng Z, Lin Y, Lin W, Zhu L, Jiang M, Wang W, Fu Q. Clinical and genetic analysis of five Chinese patients with urea cycle disorders. Mol Genet Genomic Med 2020; 8:e1301. [PMID: 32410394 PMCID: PMC7336749 DOI: 10.1002/mgg3.1301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The urea cycle plays a key role in preventing the accumulation of toxic nitrogenous waste products, including two essential enzymes: ornithine transcarbamylase (OTC) and argininosuccinate lyase (ASL). Ornithine transcarbamylase deficiency (OTCD) results from mutations in the OTC. Meanwhile, argininosuccinate lyase deficiency (ASLD) is caused by mutations in the ASL. METHODS Blood tandem mass spectrometric analysis and urea organic acidemia screening were performed on five Chinese cases, including three OTCD and two ASLD patients. Next-generation sequencing was then used to make a definite diagnosis, and the related variants were validated by Sanger sequencing. RESULTS The five patients exhibited severe clinical symptoms, with abnormal biochemical analysis and amino acids profile. Genetic analysis revealed two variants [c.77G>A (p.Arg26Gln); c.116G>T (p.Gly39Val)] in the OTC, as well as two variants [c.1311T>G (p.Tyr437*); c.961T>A (p.Tyr321Asn)] in the ASL. Conservation analysis showed that the amino acids of the two novel mutations were highly conserved in different species and were predicted to be possibly damaging with several in silico prediction programs. 3D-modeling analysis indicated that the two novel missense variants might result in modest distortions of the OTC and ASL protein structures, respectively. CONCLUSIONS Two novel variants expand the mutational spectrums of the OTC and ASL. All the results may contribute to a better understanding of the clinical course and genetic characteristics of patients with urea cycle disorders.
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Affiliation(s)
- Zhenzhu Zheng
- Neonatal Screening Center, Quanzhou Women and Children's Hospital, Quanzhou, China
| | - Yiming Lin
- Neonatal Screening Center, Quanzhou Women and Children's Hospital, Quanzhou, China
| | - Weihua Lin
- Neonatal Screening Center, Quanzhou Women and Children's Hospital, Quanzhou, China
| | - Lin Zhu
- Hangzhou Genuine Clinical Laboratory Co. Ltd, Hangzhou, China
| | - Mengyi Jiang
- Hangzhou Genuine Clinical Laboratory Co. Ltd, Hangzhou, China
| | - Wenjun Wang
- Hangzhou Genuine Clinical Laboratory Co. Ltd, Hangzhou, China
| | - Qingliu Fu
- Neonatal Screening Center, Quanzhou Women and Children's Hospital, Quanzhou, China
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16
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Sen K, Castillo Pinto C, Gropman AL. Expanding Role of Proton Magnetic Resonance Spectroscopy: Timely Diagnosis and Treatment Initiation in Partial Ornithine Transcarbamylase Deficiency. J Pediatr Genet 2020; 10:77-80. [PMID: 33552645 DOI: 10.1055/s-0040-1709670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/11/2020] [Indexed: 12/21/2022]
Abstract
We report the case of a 3-year-old male patient who presented with a 3-day history of altered mental status, emesis, and abdominal pain in the setting of a viral illness. A rapid screening revealed a high ammonia level and after reviewing his proton magnetic resonance spectroscopy (1H MRS) which showed the classic triad of high glutamate, low choline, and myoinositol, a diagnosis of ornithine transcarbamylase deficiency (OTCD) was made within 6 hours of presentation. Therapy with sodium phenylbutyrate and sodium benzoate was initiated and patient was discharged after 3 days with no neurologic disability. Biochemical and molecular testing eventually confirmed the diagnosis. 1H MRS is a practical and fast neuroimaging modality that can aid in diagnosis of OTCD and enables faster initiation of treatment in acute settings.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, District of Columbia, United States
| | - Carlos Castillo Pinto
- Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, District of Columbia, United States
| | - Andrea L Gropman
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, District of Columbia, United States
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17
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Kurtz CB, Millet YA, Puurunen MK, Perreault M, Charbonneau MR, Isabella VM, Kotula JW, Antipov E, Dagon Y, Denney WS, Wagner DA, West KA, Degar AJ, Brennan AM, Miller PF. An engineered E. coli Nissle improves hyperammonemia and survival in mice and shows dose-dependent exposure in healthy humans. Sci Transl Med 2020; 11:11/475/eaau7975. [PMID: 30651324 DOI: 10.1126/scitranslmed.aau7975] [Citation(s) in RCA: 201] [Impact Index Per Article: 50.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/08/2018] [Accepted: 12/19/2018] [Indexed: 12/30/2022]
Abstract
The intestine is a major source of systemic ammonia (NH3); thus, capturing part of gut NH3 may mitigate disease symptoms in conditions of hyperammonemia such as urea cycle disorders and hepatic encephalopathy. As an approach to the lowering of blood ammonia arising from the intestine, we engineered the orally delivered probiotic Escherichia coli Nissle 1917 to create strain SYNB1020 that converts NH3 to l-arginine (l-arg). We up-regulated arginine biosynthesis in SYNB1020 by deleting a negative regulator of l-arg biosynthesis and inserting a feedback-resistant l-arg biosynthetic enzyme. SYNB1020 produced l-arg and consumed NH3 in an in vitro system. SYNB1020 reduced systemic hyperammonemia, improved survival in ornithine transcarbamylase-deficient spfash mice, and decreased hyperammonemia in the thioacetamide-induced liver injury mouse model. A phase 1 clinical study was conducted including 52 male and female healthy adult volunteers. SYNB1020 was well tolerated at daily doses of up to 1.5 × 1012 colony-forming units administered for up to 14 days. A statistically significant dose-dependent increase in urinary nitrate, plasma 15N-nitrate (highest dose versus placebo, P = 0.0015), and urinary 15N-nitrate was demonstrated, indicating in vivo SYNB1020 activity. SYNB1020 concentrations reached steady state by the second day of dosing, and excreted cells were alive and metabolically active as evidenced by fecal arginine production in response to added ammonium chloride. SYNB1020 was no longer detectable in feces 2 weeks after the last dose. These results support further clinical development of SYNB1020 for hyperammonemia disorders including urea cycle disorders and hepatic encephalopathy.
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Affiliation(s)
| | - Yves A Millet
- Synlogic Inc., 301 Binney Street, Cambridge, MA 02142, USA
| | | | | | | | | | | | - Eugene Antipov
- Synlogic Inc., 301 Binney Street, Cambridge, MA 02142, USA
| | - Yossi Dagon
- Synlogic Inc., 301 Binney Street, Cambridge, MA 02142, USA
| | | | - David A Wagner
- Metabolic Solutions Inc., 460 Amherst Street, Nashua, NH 03063, USA
| | - Kip A West
- Synlogic Inc., 301 Binney Street, Cambridge, MA 02142, USA
| | | | | | - Paul F Miller
- Synlogic Inc., 301 Binney Street, Cambridge, MA 02142, USA
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18
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Ngu L, Winters JN, Nguyen K, Ramos KE, DeLateur NA, Makowski L, Whitford PC, Ondrechen MJ, Beuning PJ. Probing remote residues important for catalysis in Escherichia coli ornithine transcarbamoylase. PLoS One 2020; 15:e0228487. [PMID: 32027716 PMCID: PMC7004355 DOI: 10.1371/journal.pone.0228487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 01/16/2020] [Indexed: 12/14/2022] Open
Abstract
Understanding how enzymes achieve their tremendous catalytic power is a major question in biochemistry. Greater understanding is also needed for enzyme engineering applications. In many cases, enzyme efficiency and specificity depend on residues not in direct contact with the substrate, termed remote residues. This work focuses on Escherichia coli ornithine transcarbamoylase (OTC), which plays a central role in amino acid metabolism. OTC has been reported to undergo an induced-fit conformational change upon binding its first substrate, carbamoyl phosphate (CP), and several residues important for activity have been identified. Using computational methods based on the computed chemical properties from theoretical titration curves, sequence-based scores derived from evolutionary history, and protein surface topology, residues important for catalytic activity were predicted. The roles of these residues in OTC activity were tested by constructing mutations at predicted positions, followed by steady-state kinetics assays and substrate binding studies with the variants. First-layer mutations R57A and D231A, second-layer mutation H272L, and third-layer mutation E299Q, result in 57- to 450-fold reductions in kcat/KM with respect to CP and 44- to 580-fold reductions with respect to ornithine. Second-layer mutations D140N and Y160S also reduce activity with respect to ornithine. Most variants had decreased stability relative to wild-type OTC, with variants H272L, H272N, and E299Q having the greatest decreases. Variants H272L, E299Q, and R57A also show compromised CP binding. In addition to direct effects on catalytic activity, effects on overall protein stability and substrate binding were observed that reveal the intricacies of how these residues contribute to catalysis.
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Affiliation(s)
- Lisa Ngu
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, United States of America
| | - Jenifer N. Winters
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, United States of America
| | - Kien Nguyen
- Department of Physics, Northeastern University, Boston, MA, United States of America
| | - Kevin E. Ramos
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, United States of America
| | - Nicholas A. DeLateur
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, United States of America
| | - Lee Makowski
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, United States of America
- Department of Bioengineering, Northeastern University, Boston, MA, United States of America
| | - Paul C. Whitford
- Department of Physics, Northeastern University, Boston, MA, United States of America
| | - Mary Jo Ondrechen
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, United States of America
- * E-mail: (MJO); (PJB)
| | - Penny J. Beuning
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA, United States of America
- * E-mail: (MJO); (PJB)
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19
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Stepien KM, Geberhiwot T, Hendriksz CJ, Treacy EP. Challenges in diagnosing and managing adult patients with urea cycle disorders. J Inherit Metab Dis 2019; 42:1136-1146. [PMID: 30932189 DOI: 10.1002/jimd.12096] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 03/28/2019] [Indexed: 12/15/2022]
Abstract
Urea cycle disorders (UCD) are a group of rare inherited metabolic conditions of amino acid catabolism caused by an enzyme deficiency within the hepatic ammonia detoxification pathway. The presentation of these disorders ranges from life-threatening intoxication in the neonate to asymptomatic status in adults. Late-onset UCDs can present for the first time in adulthood and may mimic other causes of acute confusion or psychiatric diseases, and are often associated with neurological symptoms. Late-onset UCDs may become apparent during periods of metabolic stress such as rapid weight loss, gastric bypass surgery, chronic starvation or the postpartum period. Early diagnosis is critical for effective treatment and to prevent long-term complications of hyperammonemia. The challenges of management of adults include for example: (a) poor compliance to dietary and medical treatment which can result in recurrent hospital admissions; (b) severe neurological dysfunction; (c) the management of pregnancy and the postpartum period; and (d) access to multidisciplinary care peri-operatively. In this review, we highlight a number of challenges in the diagnosis and management of adult patient with late-onset UCDs and suggest a systematic management approach.
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Affiliation(s)
- Karolina M Stepien
- Mark Holland Metabolic Unit, Adult Inherited Metabolic Diseases Department, Salford Royal NHS Foundation Trust, Salford, UK
| | - Tarekegn Geberhiwot
- Centre for Endocrinology, Diabetes and Metabolism, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Christian J Hendriksz
- Department of Paediatrics, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa
| | - Eileen P Treacy
- National Centre for Inherited Metabolic Diseases, The Mater Misericordiae University Hospital, Dublin, Ireland
- Department of Paediatrics, Trinity College, Dublin, Ireland
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20
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Hasbaoui BE, Boujrad S, Abilkacem R, Agadr A. [Vomiting associated with weight stagnation and convulsions: urea cycle disorder should be suspected]. Pan Afr Med J 2019; 31:103. [PMID: 31037164 PMCID: PMC6462384 DOI: 10.11604/pamj.2018.31.103.11403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 08/02/2017] [Indexed: 11/11/2022] Open
Abstract
Dans certaines maladies métaboliques héréditaires, les vomissements peuvent apparaître comme un symptôme étant au premier plan, en particulier les anomalies du cycle de l'urée, qui sont habituellement diagnostiqués en période néonatale ou dans l'enfance. Nous en rapportons un cas de révélation tardive par un état de mal convulsif. Nous rapportons le cas d'une patiente âgée de 13 ans, qui a été hospitalisé pour prise en charge d'un état de mal convulsif et un retard staturo-pondéral. L'interrogatoire a révélé la notion de vomissements chroniques avec des troubles du comportement, ralentissement idéomoteur et céphalées. L'examen a trouvé une ataxie. La ponction lombaire et le scanner cérébral sont normaux. Une ammoniémie nettement augmentée est mise en évidence 75 micromoles/l (11-50). La chromatographie des acides aminés dans le sang a montré une augmentation de la glutamine et de l'alanine, La chromatographie des acides aminés dans les urines a montré une augmentation des acides aminés basiques évoquant un déficit du cycle de l'urée par déficit de l'enzyme Argininosuccinate lyase. La patiente a été traité en urgence par une alimentation exclusivement glucidolipidique, et par benzoate de sodium permettant une amélioration de l'état clinique, et une reprise de poids. Les crises convulsives ont été maîtrisées par le phénobarbital. L'enquête familiale a trouvé une sœur âgée de 20 ans suivie depuis l'âge de 3 ans pour crises convulsives traité par le phénobarbital dont le bilan métabolique réalisé dans notre service a objectivé la même anomalie du cycle de l'urée que sa sœur. A tout âge, devant une encéphalopathie avec épilepsie, vomissement, stagnation pondérale et hyperammoniémie, il faut penser à un déficit du cycle de l'urée. Le diagnostic est très souvent posé lors d'un accès neuro-digestif aigue associant vomissements, troubles de conscience et/ou crises convulsives.
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Affiliation(s)
- Brahim El Hasbaoui
- Service de Pédiatrie, Hôpital Militaire d'Instruction Mohammed V, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc
| | - Saloua Boujrad
- Service de Pédiatrie, Hôpital Militaire d'Instruction Mohammed V, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc
| | - Rachid Abilkacem
- Service de Pédiatrie, Hôpital Militaire d'Instruction Mohammed V, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc
| | - Aomar Agadr
- Service de Pédiatrie, Hôpital Militaire d'Instruction Mohammed V, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc
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21
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Buerger C, Garbade SF, Alber FD, Waisbren SE, McCarter R, Kölker S, Burgard P. Impairment of cognitive function in ornithine transcarbamylase deficiency is global rather than domain-specific and is associated with disease onset, sex, maximum ammonium, and number of hyperammonemic events. J Inherit Metab Dis 2019; 42:243-253. [PMID: 30671983 PMCID: PMC7439789 DOI: 10.1002/jimd.12013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/18/2018] [Accepted: 11/12/2018] [Indexed: 12/15/2022]
Abstract
Beginning in 2006, the Urea Cycle Disorders Consortium (UCDC) has conducted a longitudinal study of eight inherited deficiencies of enzymes and transporters of the urea cycle, including 444 individuals with ornithine transcarbamylase deficiency (OTCD), of whom 300 (67 males, 233 females) received psychological evaluation. In a cross-sectional study (age range, 3-71 years), analysis of covariance (ANCOVA) determined the association between outcomes in five cognitive domains (global intelligence, executive functions, memory, visuomotor integration, visual perception) and sex, age at testing and timing of disease onset defined as early onset (≤28 days; EO), late onset (LO), or asymptomatic (AS). The dataset of 183 subjects with complete datasets (31 males, 152 females) revealed underrepresentation of EO subjects (2 males, 4 females), who were excluded from the ANCOVA. Although mean scores of LO and AS individuals were within 1 SD of the population norm, AS subjects attained significantly higher scores than LO subjects and males higher scores than females. Correlations between cognitive domains were high, particularly intelligence proved to be a distinguished indicator for cognitive functioning. Maximum plasma ammonium concentration and intelligence correlated significantly higher in EO (r = -0.47) than in LO subjects (r = 0.04). Correlation between the number of hyperammonemic events and intelligence scores were similar for EO (r = -0.30) and LO (r = -0.26) individuals. The number of clinical symptoms was significantly associated with intelligence (r = -0.28) but not with scores in other domains. Results suggest that OTCD has a global impact on cognitive functioning rather than a specific effect on distinct cognitive domains.
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Affiliation(s)
- Corinna Buerger
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Sven F. Garbade
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Fabienne Dietrich Alber
- Division of Metabolism and Children’s Research Centre, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Susan E. Waisbren
- Division of Genetics and Genomics, Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Robert McCarter
- Center for Translational Sciences, Children’s National Health System, The George Washington University, Washington, District of Columbia
| | - Stefan Kölker
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Peter Burgard
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
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22
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Wang W, Yang J, Xue J, Mu W, Zhang X, Wu W, Xu M, Gong Y, Liu Y, Zhang Y, Xie X, Gu W, Bai J, Cram DS. A comprehensive multiplex PCR based exome-sequencing assay for rapid bloodspot confirmation of inborn errors of metabolism. BMC MEDICAL GENETICS 2019; 20:3. [PMID: 30612563 PMCID: PMC6322297 DOI: 10.1186/s12881-018-0731-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/28/2018] [Indexed: 01/22/2023]
Abstract
BACKGROUND Tandem mass spectrometry (MS MS) and simple fluorometric assays are currently used in newborn screening programs to detect inborn errors of metabolism (IEM). The aim of the study was to evaluate the clinical utility of exome sequencing as a second tier screening method to assist clinical diagnosis of the newborn. METHODS A novel PCR-exome amplification and re-sequencing (PEARS) assay was designed and used to detect mutations in 122 genes associated with 101 IEM. Newborn bloodspots positive by biochemical testing were analysed by PEARS assay to detect pathogenic mutations relevant to the IEM. RESULTS In initial validation studies of genomic DNA samples, PEARS assay correctly detected 25 known mutations associated with 17 different IEM. Retrospective gene analysis of newborns with clinical phenylketonuria (PKU), identified compound heterozygote phenylalanine hydroxylase (PAH) gene mutations in eight of nine samples (89%). Prospective analysis of 211 bloodspots correctly identified the two true PKU samples, yielding positive and negative predictive values of 100%. Testing of 8 true positive MS MS samples correctly identified potentially pathogenic compound heterozygote genotypes in 2 cases of citrullinemia type 1 and one case each of methylmalonic acidemia, isobutyryl-CoA dehydrogenase deficiency, short chain acyl-CoA dehydrogenase deficiency and glutaric acid type II and heterozygous genotypes in 2 cases of autosomal dominant methioninemia. Analysis of 11 of 12 false positive MS MS samples for other IEM identified heterozygous carriers in 8 cases for the relevant genes associated with the suspected IEM. In the remaining 3 cases, the test revealed compound heterozygote mutations in other metabolic genes not associated with the suspected IEM, indicating a misinterpretation of the original MS MS data. CONCLUSIONS The PEARS assay has clinical utility as a rapid and cost effective second-tier test to assist the clinician to accurately diagnose newborns with a suspected IEM.
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Affiliation(s)
- Wenjie Wang
- Children and Women's Hospital of Shanxi, Women Health Center of Shanxi, Taiyuan, Shanxi, China
| | - Jianping Yang
- Children and Women's Hospital of Shanxi, Newborn Disease Screening Center of Shanxi Province, Taiyuan, Shanxi, China
| | - Jinjie Xue
- Children and Women's Hospital of Shanxi, Women Health Center of Shanxi, Taiyuan, Shanxi, China
| | - Wenjuan Mu
- Children and Women's Hospital of Shanxi, Newborn Disease Screening Center of Shanxi Province, Taiyuan, Shanxi, China
| | - Xiaogang Zhang
- Children and Women's Hospital of Shanxi, Newborn Disease Screening Center of Shanxi Province, Taiyuan, Shanxi, China
| | - Wang Wu
- Beijing Berry Genomics Corporation, Building 5, Courtyard 4, Yiliaoyuan Road, ZGC Life Science Park, Beijing, 102206, Changping District, China
| | - Mengnan Xu
- Beijing Berry Genomics Corporation, Building 5, Courtyard 4, Yiliaoyuan Road, ZGC Life Science Park, Beijing, 102206, Changping District, China
| | - Yuyan Gong
- Beijing Berry Genomics Corporation, Building 5, Courtyard 4, Yiliaoyuan Road, ZGC Life Science Park, Beijing, 102206, Changping District, China
| | - Yiqian Liu
- Beijing Berry Genomics Corporation, Building 5, Courtyard 4, Yiliaoyuan Road, ZGC Life Science Park, Beijing, 102206, Changping District, China
| | - Yu Zhang
- Beijing Berry Genomics Corporation, Building 5, Courtyard 4, Yiliaoyuan Road, ZGC Life Science Park, Beijing, 102206, Changping District, China
| | - Xiaobing Xie
- Beijing Chigene Translational Medicial Research Center Co., Beijing, 101111, China
| | - Weiyue Gu
- Beijing Chigene Translational Medicial Research Center Co., Beijing, 101111, China
| | - Jigeng Bai
- Children and Women's Hospital of Shanxi, Women Health Center of Shanxi, Taiyuan, Shanxi, China
| | - David S Cram
- Children and Women's Hospital of Shanxi, Women Health Center of Shanxi, Taiyuan, Shanxi, China. .,Beijing Berry Genomics Corporation, Building 5, Courtyard 4, Yiliaoyuan Road, ZGC Life Science Park, Beijing, 102206, Changping District, China.
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23
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Pizzi MA, Alejos D, Hasan TF, Atwal PS, Krishnaiengar SR, Freeman WD. Adult Presentation of Ornithine Transcarbamylase Deficiency: 2 Illustrative Cases of Phenotypic Variability and Literature Review. Neurohospitalist 2019; 9:30-36. [PMID: 30671162 PMCID: PMC6327241 DOI: 10.1177/1941874418764817] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ornithine transcarbamylase (OTC) deficiency is an X-linked recessive disorder that usually presents in the neonatal period. Late-onset presentation of OTC can cause mild to severe symptoms. We describe laboratory and clinical findings of late-onset presentations of OTC deficiency. We conducted a literature search using search terms "ornithine transcarbamylase deficiency," "late onset presentation," and "hyperammonemia" from January 1, 1987, to December 31, 2016, was performed. Only papers published in English were included. We searched on PubMed, MEDLINE, and Google Scholar. We also present 2 OTC deficiency cases. A total of 30 adult cases had late-onset presentation of OTC deficiency reported. The majority were women (57%) with a median age of 37 years. The median level of ammonia was 308 mmol/L and the mortality rate was 30%. Our case 1 was a 40-year-old woman who succumbed to neurologic complications after a hyperammonemia crisis following an increased protein intake. Our case 2 was a 43-year-old woman with seizures associated with increased ammonia levels. Our 2 case reports show the wide phenotypic variability and severity in late-onset presentation of OTC ranging from seizures to cerebral herniation. Our literature review is the first to detail published laboratory and neurologic sequelae of late-onset OTC deficiency.
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Affiliation(s)
| | - David Alejos
- Department of Critical Care, Mayo Clinic, Jacksonville, FL, USA
| | - Tasneem F. Hasan
- Department of Neurologic Surgery, Mayo Clinic, Jacksonville, FL, USA
| | - Paldeep S. Atwal
- Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL, USA
| | | | - William D. Freeman
- Department of Neurology, Mayo Clinic, Jacksonville, FL, USA
- Department of Critical Care, Mayo Clinic, Jacksonville, FL, USA
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24
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Laróvere LE, Silvera Ruiz SM, Arranz JA, Dodelson de Kremer R. Mutation Spectrum and Genotype–Phenotype Correlation in a Cohort of Argentine Patients with Ornithine Transcarbamylase Deficiency: A Single-Center Experience. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2018. [DOI: 10.1177/2326409818813177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Laura E. Laróvere
- Centro de Estudio de las Metabolopatías Congénitas, Hospital de Niños de la Santísima Trinidad; Cátedra de Clínica Pediátrica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina, Ferroviarios 1250 – 5014 – Córdoba Argentina
| | - Silene M. Silvera Ruiz
- Centro de Estudio de las Metabolopatías Congénitas, Hospital de Niños de la Santísima Trinidad; Cátedra de Clínica Pediátrica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina, Ferroviarios 1250 – 5014 – Córdoba Argentina
| | - José A. Arranz
- Laboratori de Metabolopaties, Hospital Universitari Vall d'Hebron Barcelona, España
| | - Raquel Dodelson de Kremer
- Centro de Estudio de las Metabolopatías Congénitas, Hospital de Niños de la Santísima Trinidad; Cátedra de Clínica Pediátrica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina, Ferroviarios 1250 – 5014 – Córdoba Argentina
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25
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Abstract
The life expectancy and quality of life of women with genetic disorders continues to improve, resulting in more women reaching reproductive age and desiring fertility. It is becoming increasingly important that obstetricians become familiar with common genetic disorders and their associated risks in pregnancy. The authors review pregnancy in women with various genetic disorders, including review of pregnancy outcomes, management recommendations, and genetic risk assessment. Most data on pregnancies in women with genetic conditions are based on case reports and literature reviews. Additional studies, including pregnancy registries, are needed to improve our understanding and care of this patient population.
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Affiliation(s)
- Sarah Harris
- University of North Carolina at Chapel Hill School of Medicine, 3010 Old Clinic Building, CB 7516, Chapel Hill, NC 27516, USA
| | - Neeta L Vora
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill School of Medicine, 3010 Old Clinic Building, CB 7516, Chapel Hill, NC 27516, USA.
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26
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Mutation Study of Malaysian Patients with Ornithine Transcarbamylase Deficiency: Clinical, Molecular, and Bioinformatics Analyses of Two Novel Missense Mutations of the OTC Gene. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4320831. [PMID: 30175132 PMCID: PMC6098936 DOI: 10.1155/2018/4320831] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/25/2018] [Accepted: 06/20/2018] [Indexed: 12/16/2022]
Abstract
Ornithine transcarbamylase deficiency (OTCD), an X-linked disorder that results from mutations in the OTC gene, causes hyperammonemia and leads to various clinical manifestations. Mutations occurring close to the catalytic site of OTCase can cause severe OTCD phenotypes compared with those caused by mutations occurring on the surface of this protein. In this study, we report two novel OTC missense mutations, Q171H and N199H, found in Malaysian patients. Q171H and N199H caused neonatal onset OTCD in a male and late OTCD in a female, respectively. In silico predictions and molecular docking were performed to examine the effect of these novel mutations, and the results were compared with other 30 known OTC mutations. In silico servers predicted that Q171H and N199H, as well as 30 known missense mutations, led to the development of OTCD. Docking analysis indicated that N-(phosphonoacetyl)-L-ornithine (PALO) was bound to the catalytic site of OTCase mutant structure with minimal conformational changes. However, the mutations disrupted interatomic interactions in the catalytic site. Therefore, depending on the severity of disruption occurring at the catalytic site, the mutation may affect the efficiency of mechanism and functions of OTCase.
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27
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Lee T, Misaki M, Shimomura H, Tanaka Y, Yoshida S, Murayama K, Nakamura K, Fujiki R, Ohara O, Sasai H, Fukao T, Takeshima Y. Late-onset ornithine transcarbamylase deficiency caused by a somatic mosaic mutation. Hum Genome Var 2018; 5:22. [PMID: 30131866 PMCID: PMC6095930 DOI: 10.1038/s41439-018-0022-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 06/12/2018] [Accepted: 07/12/2018] [Indexed: 01/18/2023] Open
Abstract
An 18-month-old boy was diagnosed with late-onset ornithine transcarbamylase deficiency. Genetic analysis revealed a mosaic frameshift mutation (p.Q279fs) in the OTC gene. Despite the presence of a null mutation, he exhibited a milder phenotype, suggesting that the wild-type allele could rescue the function of OTC. The presence of mosaicism has great effects on the clinical phenotype and recurrence-risk assessment, which should be taken into consideration for genetic counseling.
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Affiliation(s)
- Tomoko Lee
- 1Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan
| | - Maiko Misaki
- 1Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan
| | - Hideki Shimomura
- 1Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan
| | - Yasuhiko Tanaka
- 1Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan
| | - Satoru Yoshida
- 2Department of Pediatrics, Seirei Mikatahara General Hospital, Hamamatsu, Japan
| | - Kei Murayama
- 3Center for Medical Genetics and Department of Metabolism, Chiba Children's Hospital, Chiba, Japan
| | - Kimitoshi Nakamura
- 4Department of Pediatrics, Kumamoto University Graduate School of Medicine, Kumamoto, Japan
| | - Ryoji Fujiki
- 5Department of Technology Development, Kazusa DNA Research Institute, Chiba, Japan
| | - Osamu Ohara
- 5Department of Technology Development, Kazusa DNA Research Institute, Chiba, Japan
| | - Hideo Sasai
- 6Department of Pediatrics, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Toshiyuki Fukao
- 6Department of Pediatrics, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Yasuhiro Takeshima
- 1Department of Pediatrics, Hyogo College of Medicine, Nishinomiya, Japan
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28
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Crowe L, Anderson V, Hardikar W, Boneh A. Cognitive and Behavioural Outcomes of Paediatric Liver Transplantation for Ornithine Transcarbamylase Deficiency. JIMD Rep 2018; 43:19-25. [PMID: 29524203 PMCID: PMC6323017 DOI: 10.1007/8904_2018_97] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 02/19/2023] Open
Abstract
Ornithine Trans-Carbamylase (OTC) deficiency is the most common disorder of the urea cycle. Cognitive impairments in skills such as attention and executive function have been reported in individuals with OTC deficiency who are managed with medication. In some cases, children undergo liver transplantation (LTx) to correct the metabolic defect. The metabolic and medical outcomes of LTx are generally good. However, little is known about the impacts on cognition. In this study, four children (three female) completed detailed neuropsychological batteries prior to (n = 6) and following LTx (n = 8 assessments). Children's age at assessment ranged from 3 to 11 years. The battery included standardised, age-referenced measures of intellectual ability (IQ), attention, memory and educational ability. Additionally, parent measures of behaviour and executive function were administered. Generally, there was little change in overall IQ following LTx. Memory and academic skills were at expected levels for the three female patients and gains were made after LTx. Children showed ongoing impairments in attention and parent rated executive function. In conclusion, the immediate effect of LTx on cognition may not appear beneficial in the short-term and impairments in IQ, attention and behaviour persisted after the procedure. However, LTx seems to enable stabilisation to premorbid function in the longer term.
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Affiliation(s)
- Louise Crowe
- School of Psychological Sciences, University of Melbourne, Parkville, VIC, Australia.
- Child Neuropsychology, Murdoch Children's Research Institute, Melbourne, VIC, Australia.
- Department of Psychology, Royal Children's Hospital, Melbourne, VIC, Australia.
| | - Vicki Anderson
- School of Psychological Sciences, University of Melbourne, Parkville, VIC, Australia
- Child Neuropsychology, Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Psychology, Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Winita Hardikar
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Department of Gastroenterology and Nutrition, Royal Children's Hospital, Melbourne, VIC, Australia
| | - Avihu Boneh
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Metabolic Research, Murdoch Children's Research Institute, Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Metabolic Medicine, Royal Children's Hospital, Melbourne, VIC, Australia
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29
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Jang YJ, LaBella AL, Feeney TP, Braverman N, Tuchman M, Morizono H, Ah Mew N, Caldovic L. Disease-causing mutations in the promoter and enhancer of the ornithine transcarbamylase gene. Hum Mutat 2018; 39:527-536. [PMID: 29282796 DOI: 10.1002/humu.23394] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 12/19/2017] [Accepted: 12/21/2017] [Indexed: 12/17/2022]
Abstract
The ornithine transcarbamylase (OTC) gene is on the X chromosome and its product catalyzes the formation of citrulline from ornithine and carbamylphosphate in the urea cycle. About 10%-15% of patients, clinically diagnosed with OTC deficiency (OTCD), lack identifiable mutations in the coding region or splice junctions of the OTC gene on routine molecular testing. We collected DNA from such patients via retrospective review and by prospective enrollment. In nine of 38 subjects (24%), we identified a sequence variant in the OTC regulatory regions. Eight subjects had unique sequence variants in the OTC promoter and one subject had a novel sequence variant in the OTC enhancer. All sequence variants affect positions that are highly conserved in mammalian OTC genes. Functional studies revealed reduced reporter gene expression with all sequence variants. Two sequence variants caused decreased binding of the HNF4 transcription factor to its mutated binding site. Bioinformatic analyses combined with functional assays can be used to identify and authenticate pathogenic sequence variants in regulatory regions of the OTC gene, in other urea cycle disorders or other inborn errors of metabolism.
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Affiliation(s)
- Yoon J Jang
- Center for Genetic Medicine Research, Children's National Health System, Washington, District of Columbia
| | - Abigail L LaBella
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee
| | - Timothy P Feeney
- Harvard T.H. Chan School of Public Health, Harvard University, Cambridge, Massachusetts
| | - Nancy Braverman
- McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Mendel Tuchman
- Center for Genetic Medicine Research, Children's National Health System, Washington, District of Columbia
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children's National Health System, Washington, District of Columbia
| | - Nicholas Ah Mew
- Center for Translational Sciences, Children's National Health System, Washington, District of Columbia
| | - Ljubica Caldovic
- Center for Genetic Medicine Research, Children's National Health System, Washington, District of Columbia
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30
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Survival of a Male Infant with a Familial Xp11.4 Deletion Causing Ornithine Transcarbamylase Deficiency. JIMD Rep 2018; 45:83-87. [DOI: 10.1007/8904_2018_145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 09/14/2018] [Accepted: 09/17/2018] [Indexed: 11/25/2022] Open
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31
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Shao Y, Jiang M, Lin Y, Mei H, Zhang W, Cai Y, Su X, Hu H, Li X, Liu L. Clinical and mutation analysis of 24 Chinese patients with ornithine transcarbamylase deficiency. Clin Genet 2017; 92:318-322. [DOI: 10.1111/cge.13004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/27/2017] [Accepted: 03/02/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Y. Shao
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - M. Jiang
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - Y. Lin
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - H. Mei
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - W. Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - Y. Cai
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - X. Su
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - H. Hu
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - X. Li
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
| | - L. Liu
- Department of Pediatric Endocrinology and Genetic Metabolism; Guangzhou Women and Children's Medical Center; Guangzhou China
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32
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Urea Cycle Defects: Early-Onset Disease Associated with A208T Mutation in OTC Gene-Expanding the Clinical Phenotype. Case Rep Genet 2017; 2017:1048717. [PMID: 28261508 PMCID: PMC5316440 DOI: 10.1155/2017/1048717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/17/2017] [Indexed: 12/30/2022] Open
Abstract
Ornithine transcarbamylase deficiency (OMIM: 311250) is the most common disorder of urea cycle disorders, accounting for nearly 50% of all cases. We report a case of a two-month- old male patient, who attends our medical genetics consultation because of low citrulline levels and elevated glutamine to citrulline ratio detected by expanded newborn screening with tandem mass spectrometry. He is an asymptomatic male with a normal physical examination and appropriate neurodevelopmental milestones. The patient has a family history of one older brother who died at 18 months old from severe and sudden hyperammonemia and a maternal aunt who suddenly died at two years old. He had high plasma ammonium concentration and a confirmed OTC mutation (p.A208T). Usually, this mutation causes OTC deficiency of late onset in adult males. However, this report raises awareness about mutations previously described as a late-onset causing disease, which can cause severe hyperammonemia and high risk of dying at an early age.
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Laemmle A, Gallagher RC, Keogh A, Stricker T, Gautschi M, Nuoffer JM, Baumgartner MR, Häberle J. Frequency and Pathophysiology of Acute Liver Failure in Ornithine Transcarbamylase Deficiency (OTCD). PLoS One 2016; 11:e0153358. [PMID: 27070778 PMCID: PMC4829252 DOI: 10.1371/journal.pone.0153358] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/29/2016] [Indexed: 12/13/2022] Open
Abstract
Background Acute liver failure (ALF) has been reported in ornithine transcarbamylase deficiency (OTCD) and other urea cycle disorders (UCD). The frequency of ALF in OTCD is not well-defined and the pathogenesis is not known. Aim To evaluate the prevalence of ALF in OTCD, we analyzed the Swiss patient cohort. Laboratory data from 37 individuals, 27 females and 10 males, diagnosed between 12/1991 and 03/2015, were reviewed for evidence of ALF. In parallel, we performed cell culture studies using human primary hepatocytes from a single patient treated with ammonium chloride in order to investigate the inhibitory potential of ammonia on hepatic protein synthesis. Results More than 50% of Swiss patients with OTCD had liver involvement with ALF at least once in the course of disease. Elevated levels of ammonia often correlated with (laboratory) coagulopathy as reflected by increased values for international normalized ratio (INR) and low levels of hepatic coagulation factors which did not respond to vitamin K. In contrast, liver transaminases remained normal in several cases despite massive hyperammonemia and liver involvement as assessed by pathological INR values. In our in vitro studies, treatment of human primary hepatocytes with ammonium chloride for 48 hours resulted in a reduction of albumin synthesis and secretion by approximately 40%. Conclusion In conclusion, ALF is a common complication of OTCD, which may not always lead to severe symptoms and may therefore be underdiagnosed. Cell culture experiments suggest an ammonia-induced inhibition of hepatic protein synthesis, thus providing a possible pathophysiological explanation for hyperammonemia-associated ALF.
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Affiliation(s)
- Alexander Laemmle
- Division of Metabolism and Children`s Research Center (CRC), University Children`s Hospital, Zurich, Switzerland
- radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- * E-mail: ;
| | - Renata C. Gallagher
- Department of Pediatrics, Medical Genetics, University of California San Francisco, San Francisco, United States of America
| | - Adrian Keogh
- Department of Clinical Research and Clinic for Visceral Surgery and Medicine, Bern University Hospital, Bern, Switzerland
| | - Tamar Stricker
- Division of Metabolism and Children`s Research Center (CRC), University Children`s Hospital, Zurich, Switzerland
| | - Matthias Gautschi
- Department of Pediatrics, University Children's Hospital, Bern, Switzerland
- University Institute of Clinical Chemistry, University of Bern, Bern, Switzerland
| | - Jean-Marc Nuoffer
- Department of Pediatrics, University Children's Hospital, Bern, Switzerland
- University Institute of Clinical Chemistry, University of Bern, Bern, Switzerland
| | - Matthias R. Baumgartner
- Division of Metabolism and Children`s Research Center (CRC), University Children`s Hospital, Zurich, Switzerland
- radiz–Rare Disease Initiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Johannes Häberle
- Division of Metabolism and Children`s Research Center (CRC), University Children`s Hospital, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
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Mahmood T, Nugent K. Nonhepatic hyperammonemic encephalopathy due to undiagnosed urea cycle disorder. Proc (Bayl Univ Med Cent) 2015; 28:375-7. [PMID: 26130895 DOI: 10.1080/08998280.2015.11929281] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ornithine transcarbamoylase deficiency is the most common inherited urea cycle disorder. In adults, its phenotypes are diverse. In asymptomatic patients with late presentations, symptom onset is often associated with a precipitating factor. We present a case of a woman with urea cycle disorder diagnosed after an acute peptic ulcer bleed and fasting.
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Affiliation(s)
- Tashfeen Mahmood
- Department of Internal Medicine, Texas Tech University Health Science Center, Lubbock, Texas
| | - Kenneth Nugent
- Department of Internal Medicine, Texas Tech University Health Science Center, Lubbock, Texas
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Pacheco-Colón I, Washington SD, Sprouse C, Helman G, Gropman AL, VanMeter JW. Reduced Functional Connectivity of Default Mode and Set-Maintenance Networks in Ornithine Transcarbamylase Deficiency. PLoS One 2015; 10:e0129595. [PMID: 26067829 PMCID: PMC4466251 DOI: 10.1371/journal.pone.0129595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 05/11/2015] [Indexed: 12/21/2022] Open
Abstract
Background and Purpose Ornithine transcarbamylase deficiency (OTCD) is an X-chromosome linked urea cycle disorder (UCD) that causes hyperammonemic episodes leading to white matter injury and impairments in executive functioning, working memory, and motor planning. This study aims to investigate differences in functional connectivity of two resting-state networks—default mode and set-maintenance—between OTCD patients and healthy controls. Methods Sixteen patients with partial OTCD and twenty-two control participants underwent a resting-state scan using 3T fMRI. Combining independent component analysis (ICA) and region-of-interest (ROI) analyses, we identified the nodes that comprised each network in each group, and assessed internodal connectivity. Results Group comparisons revealed reduced functional connectivity in the default mode network (DMN) of OTCD patients, particularly between the anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC) node and bilateral inferior parietal lobule (IPL), as well as between the ACC/mPFC node and the posterior cingulate cortex (PCC) node. Patients also showed reduced connectivity in the set-maintenance network, especially between right anterior insula/frontal operculum (aI/fO) node and bilateral superior frontal gyrus (SFG), as well as between the right aI/fO and ACC and between the ACC and right SFG. Conclusion Internodal functional connectivity in the DMN and set-maintenance network is reduced in patients with partial OTCD compared to controls, most likely due to hyperammonemia-related white matter damage. Because several of the affected areas are involved in executive functioning, it is postulated that this reduced connectivity is an underlying cause of the deficits OTCD patients display in this cognitive domain.
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Affiliation(s)
- Ileana Pacheco-Colón
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurology, Georgetown University Medical Center, Washington, DC, United States of America
- * E-mail:
| | - Stuart D. Washington
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurology, Georgetown University Medical Center, Washington, DC, United States of America
| | - Courtney Sprouse
- Department of Neurogenetics, Children’s National Health System, Washington, DC, United States of America
- George Washington University of the Health Sciences, Washington, DC, United States of America
| | - Guy Helman
- Department of Neurogenetics, Children’s National Health System, Washington, DC, United States of America
| | - Andrea L. Gropman
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurogenetics, Children’s National Health System, Washington, DC, United States of America
- George Washington University of the Health Sciences, Washington, DC, United States of America
- Medical Genetics Branch, NHGRI, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John W. VanMeter
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurology, Georgetown University Medical Center, Washington, DC, United States of America
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Clinical outcomes and the mutation spectrum of the OTC gene in patients with ornithine transcarbamylase deficiency. J Hum Genet 2015; 60:501-7. [DOI: 10.1038/jhg.2015.54] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 04/11/2015] [Indexed: 11/08/2022]
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Genotype-Phenotype Correlations in Ornithine Transcarbamylase Deficiency: A Mutation Update. J Genet Genomics 2015; 42:181-94. [PMID: 26059767 DOI: 10.1016/j.jgg.2015.04.003] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 04/05/2015] [Accepted: 04/08/2015] [Indexed: 12/31/2022]
Abstract
Ornithine transcarbamylase (OTC) deficiency is an X-linked trait that accounts for nearly half of all inherited disorders of the urea cycle. OTC is one of the enzymes common to both the urea cycle and the bacterial arginine biosynthesis pathway; however, the role of OTC has changed over evolution. For animals with a urea cycle, defects in OTC can trigger hyperammonemic episodes that can lead to brain damage and death. This is the fifth mutation update for human OTC with previous updates reported in 1993, 1995, 2002, and 2006. In the 2006 update, 341 mutations were reported. This current update contains 417 disease-causing mutations, and also is the first report of this series to incorporate information about natural variation of the OTC gene in the general population through examination of publicly available genomic data and examination of phenotype/genotype correlations from patients participating in the Urea Cycle Disorders Consortium Longitudinal Study and the first to evaluate the suitability of systematic computational approaches to predict severity of disease associated with different types of OTC mutations.
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Brassier A, Gobin S, Arnoux JB, Valayannopoulos V, Habarou F, Kossorotoff M, Servais A, Barbier V, Dubois S, Touati G, Barouki R, Lesage F, Dupic L, Bonnefont JP, Ottolenghi C, De Lonlay P. Long-term outcomes in Ornithine Transcarbamylase deficiency: a series of 90 patients. Orphanet J Rare Dis 2015; 10:58. [PMID: 25958381 PMCID: PMC4443534 DOI: 10.1186/s13023-015-0266-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/13/2015] [Indexed: 12/11/2022] Open
Abstract
Background The principal aim of this study was to investigate the long-term outcomes of a large cohort of patients with ornithine transcarbamylase deficiency (OTCD) who were followed up at a single medical center. Methods We analyzed clinical, biochemical and genetic parameters of 90 patients (84 families, 48 males and 42 females) with OTCD between 1971 and 2011. Results Twenty-seven patients (22 boys, 5 girls) had a neonatal presentation; 52 patients had an “intermediate” late-onset form of the disease (21 boys, 31 girls) that was revealed between 1 month and 16 years; and 11 patients (5 boys, 6 girls) presented in adulthood (16 to 55 years). Patients with a neonatal presentation had increased mortality (90% versus 13% in late-onset forms) and peak plasma ammonium (mean value: 960 μmol/L versus 500 μmol/L) and glutamine (mean value: 4110 μmol/L versus 1000 μmol/L) levels at diagnosis. All of the neonatal forms displayed a greater number of acute decompensations (mean value: 6.2/patient versus 2.5 and 1.4 in infants and adults, respectively). In the adult group, some patients even recently died at the time of presentation during their first episode of coma. Molecular analyses identified a deleterious mutation in 59/68 patients investigated. Single base substitutions were detected more frequently than deletions (69% and 12%, respectively), with a recurrent mutation identified in the late-onset groups (pArg40 His; 13% in infants, 57% in adults); inherited mutations represented half of the cases. The neurological score did not differ significantly between the patients who were alive in the neonatal or late-onset groups and did not correlate with the peak ammonia and plasma glutamine concentrations at diagnosis. However, in late-onset forms of the disease, ammonia levels adjusted according to the glutamine/citrulline ratio at diagnosis were borderline predictors of low IQ (p = 0.12 by logistic regression; area under the receiver operating characteristic curve of 76%, p <0.05). Conclusions OTCD remains a severe disease, even in adult-onset patients for whom the prevention of metabolic decompensations is crucial. The combination of biochemical markers warrants further investigations to provide additional prognostic information regarding the neurological outcomes of patients with OTCD.
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Affiliation(s)
- Anais Brassier
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France. .,Université Paris Descartes, Institut Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | - Stephanie Gobin
- Service de Génétique, Paris, France. .,Université Paris Descartes, Institut Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | - Jean Baptiste Arnoux
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France.
| | - Vassili Valayannopoulos
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France.
| | - Florence Habarou
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France. .,Service de Biochimie Métabolique, Paris, France. .,Université Paris Descartes, Institut Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | - Manoelle Kossorotoff
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France.
| | - Aude Servais
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France.
| | - Valerie Barbier
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France.
| | - Sandrine Dubois
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France.
| | - Guy Touati
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France.
| | - Robert Barouki
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France. .,Service de Biochimie Métabolique, Paris, France. .,Université Paris Descartes, Institut Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | - Fabrice Lesage
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France. .,Service de Réanimation pédiatrique, Paris, France.
| | - Laurent Dupic
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France. .,Service de Réanimation pédiatrique, Paris, France.
| | - Jean Paul Bonnefont
- Service de Génétique, Paris, France. .,Université Paris Descartes, Institut Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | - Chris Ottolenghi
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France. .,Service de Biochimie Métabolique, Paris, France. .,Université Paris Descartes, Institut Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France.
| | - Pascale De Lonlay
- Reference Center of Inherited Metabolic Diseases and units of metabolism and neurology, 149 rue de Sèvres, 75015, Paris, France. .,Université Paris Descartes, Institut Imagine, Hôpital Necker-Enfants Malades, APHP, Paris, France.
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Functional characterization of the spf/ash splicing variation in OTC deficiency of mice and man. PLoS One 2015; 10:e0122966. [PMID: 25853564 PMCID: PMC4390381 DOI: 10.1371/journal.pone.0122966] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 02/16/2015] [Indexed: 12/27/2022] Open
Abstract
The spf/ash mouse model of ornithine transcarbamylase (OTC) deficiency, a severe urea cycle disorder, is caused by a mutation (c.386G>A; p.R129H) in the last nucleotide of exon 4 of the Otc gene, affecting the 5' splice site and resulting in partial use of a cryptic splice site 48 bp into the adjacent intron. The equivalent nucleotide change and predicted amino acid change is found in OTC deficient patients. Here we have used liver tissue and minigene assays to dissect the transcriptional profile resulting from the "spf/ash" mutation in mice and man. For the mutant mouse, we confirmed liver transcripts corresponding to partial intron 4 retention by the use of the c.386+48 cryptic site and to normally spliced transcripts, with exon 4 always containing the c.386G>A (p.R129H) variant. In contrast, the OTC patient exhibited exon 4 skipping or c.386G>A (p.R129H)-variant exon 4 retention by using the natural or a cryptic splice site at nucleotide position c.386+4. The corresponding OTC tissue enzyme activities were between 3-6% of normal control in mouse and human liver. The use of the cryptic splice sites was reproduced in minigenes carrying murine or human mutant sequences. Some normally spliced transcripts could be detected in minigenes in both cases. Antisense oligonucleotides designed to block the murine cryptic +48 site were used in minigenes in an attempt to redirect splicing to the natural site. The results highlight the relevance of in depth investigations of the molecular mechanisms of splicing mutations and potential therapeutic approaches. Notably, they emphasize the fact that findings in animal models may not be applicable for human patients due to the different genomic context of the mutations.
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Tarasenko TN, Rosas OR, Singh LN, Kristaponis K, Vernon H, McGuire PJ. A new mouse model of mild ornithine transcarbamylase deficiency (spf-j) displays cerebral amino acid perturbations at baseline and upon systemic immune activation. PLoS One 2015; 10:e0116594. [PMID: 25647322 PMCID: PMC4315515 DOI: 10.1371/journal.pone.0116594] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 12/12/2014] [Indexed: 01/09/2023] Open
Abstract
Ornithine transcarbamylase deficiency (OTCD, OMIM# 311250) is an inherited X-linked urea cycle disorder that is characterized by hyperammonemia and orotic aciduria. In this report, we describe a new animal model of OTCD caused by a spontaneous mutation in the mouse Otc gene (c.240T>A, p.K80N). This transversion in exon 3 of ornithine transcarbamylase leads to normal levels of mRNA with low levels of mature protein and is homologous to a mutation that has also been described in a single patient affected with late-onset OTCD. With higher residual enzyme activity, spf-J were found to have normal plasma ammonia and orotate. Baseline plasma amino acid profiles were consistent with mild OTCD: elevated glutamine, and lower citrulline and arginine. In contrast to WT, spf-J displayed baseline elevations in cerebral amino acids with depletion following immune challenge with polyinosinic:polycytidylic acid. Our results indicate that the mild spf-J mutation constitutes a new mouse model that is suitable for mechanistic studies of mild OTCD and the exploration of cerebral pathophysiology during acute decompensation that characterizes proximal urea cycle dysfunction in humans.
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Affiliation(s)
- Tatyana N Tarasenko
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Odrick R Rosas
- Universidad Central de Caribe, Bayamon, Puerto Rico, United States of America
| | - Larry N Singh
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kara Kristaponis
- Department of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Hilary Vernon
- Kennedy Krieger Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Peter J McGuire
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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Fujisawa D, Mitsubuchi H, Matsumoto S, Iwai M, Nakamura K, Hoshide R, Harada N, Yoshino M, Endo F. Early intervention for late-onset ornithine transcarbamylase deficiency. Pediatr Int 2015; 57:e1-3. [PMID: 25711267 DOI: 10.1111/ped.12457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 07/03/2014] [Accepted: 07/14/2014] [Indexed: 11/28/2022]
Abstract
We report the case of a family with late-onset ornithine transcarbamylase deficiency (OTCD). Several family members had died from OTCD, and the c.221G>A, p.Lys221Lys mutation was detected at the 3' end of exon 6 of OTC in the X-chromosome of some members. We provided genetic counseling on pregnancy, delivery, and neonate management to a 4th-generation female carrier and decided on metabolic management of her child from birth. Two male patients were diagnosed with late-onset OTCD on the basis of blood amino acid and genetic analysis, and they received arginine supplementation from the asymptomatic, early neonatal period. These children grew and developed normally, without decompensation. Patients with late-onset OTCD can and should be diagnosed and treated in the early neonatal period, especially those from families already diagnosed with late-onset OTCD, and family members must be provided with genetic counseling.
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Affiliation(s)
- Daisuke Fujisawa
- Department of Pediatrics, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
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Singh S, Suresh S, McClave SA, Cave M. Treating Every Needle in the Haystack. JPEN J Parenter Enteral Nutr 2014; 39:977-85. [DOI: 10.1177/0148607114546900] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/20/2014] [Indexed: 12/16/2022]
Affiliation(s)
- Sanjeev Singh
- Department of General Internal Medicine, Palliative Medicine and Medical Education, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Swetha Suresh
- Department of General Internal Medicine, Palliative Medicine and Medical Education, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
- Department Pediatrics, University of Louisville School of Medicine, Louisville, Kentucky
| | - Stephen A. McClave
- Department of General Internal Medicine, Palliative Medicine and Medical Education, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Matt Cave
- Department of General Internal Medicine, Palliative Medicine and Medical Education, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
- Department of Pharmacology & Toxicology, University of Louisville, Louisville, Kentucky
- Robley Rex Louisville VAMC, Louisville, Kentucky
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Late-onset ornithine carbamoyltransferase deficiency accompanying acute pancreatitis and hyperammonemia. Case Rep Med 2013; 2013:903546. [PMID: 24073003 PMCID: PMC3773375 DOI: 10.1155/2013/903546] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 07/31/2013] [Indexed: 12/31/2022] Open
Abstract
Hyperammonemia related to urea cycle disorders is a rare cause of potentially fatal encephalopathy that is encountered in intensive care units (ICUs). Left undiagnosed, this condition may manifest irreversible neuronal damage. However, timely diagnosis and treatment initiation can be facilitated simply by increased awareness of the ICU staff. Here, we describe a patient with acute severe pancreatitis who developed hyperammonemia and encephalopathy without liver disease. Urea cycle disorder was suspected and hemodialysis was initiated. Following reduction of ammonia levels, subsequent treatment included protein restriction and administration of arginine and sodium benzoate. The patient was discharged to home after 47 days with plasma ammonia within normal range and without neurological symptoms. In clinical care settings, patients with neurological symptoms unexplained by the present illness should be assessed for serum ammonia levels to disclose any urea cycle disorders to initiate timely treatment and improve outcome.
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Storkanova G, Vlaskova H, Chuzhanova N, Zeman J, Stranecky V, Majer F, Peskova K, Luksan O, Jirsa M, Hrebicek M, Dvorakova L. Ornithine carbamoyltransferase deficiency: molecular characterization of 29 families. Clin Genet 2013; 84:552-9. [DOI: 10.1111/cge.12085] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 12/21/2012] [Accepted: 12/21/2012] [Indexed: 11/30/2022]
Affiliation(s)
- G Storkanova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - H Vlaskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - N Chuzhanova
- School of Science and Technology; Nottingham Trent University; Nottingham NG11 8NS UK
| | - J Zeman
- Department of Paediatrics and Adolescent Medicine; First Faculty of Medicine, Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - V Stranecky
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - F Majer
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - K Peskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - O Luksan
- Laboratory of Experimental Hepatology; Institute for Clinical and Experimental Medicine (IKEM); Prague Czech Republic
| | - M Jirsa
- Laboratory of Experimental Hepatology; Institute for Clinical and Experimental Medicine (IKEM); Prague Czech Republic
| | - M Hrebicek
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
| | - L Dvorakova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine; Charles University in Prague, and General University Hospital in Prague; Czech Republic
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Mew NA, Krivitzky L, McCarter R, Batshaw M, Tuchman M. Clinical outcomes of neonatal onset proximal versus distal urea cycle disorders do not differ. J Pediatr 2013; 162:324-9.e1. [PMID: 22901741 PMCID: PMC4440324 DOI: 10.1016/j.jpeds.2012.06.065] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 05/17/2012] [Accepted: 06/29/2012] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To compare the clinical course and outcome of patients diagnosed with one of 4 neonatal-onset urea cycle disorders (UCDs): deficiency of carbamyl phosphate synthase 1 (CPSD), ornithine transcarbamylase (OTCD), argininosuccinate synthase (ASD), or argininosuccinate lyase (ALD). STUDY DESIGN Clinical, biochemical, and neuropsychological data from 103 subjects with neonatal-onset UCDs were derived from the Longitudinal Study of Urea Cycle Disorders, an observational protocol of the Urea Cycle Disorders Consortium, one of the Rare Disease Clinical Research Networks. RESULTS Some 88% of the subjects presented clinically by age 7 days. Peak ammonia level was 963 μM in patients with proximal UCDs (CPSD or OTCD), compared with 589 μM in ASD and 573 μM in ALD. Roughly 25% of subjects with CPSD or OTCD, 18% of those with ASD, and 67% of those with ALD had a "honeymoon period," defined as the time interval from discharge from initial admission to subsequent admission for hyperammonemia, greater than 1 year. The proportion of patients with a poor outcome (IQ/Developmental Quotient <70) was greatest in ALD (68%), followed by ASD (54%) and CPSD/OTCD (47%). This trend was not significant, but was observed in both patients aged <4 years and those aged ≥ 4 years. Poor cognitive outcome was not correlated with peak ammonia level or duration of initial admission. CONCLUSION Neurocognitive outcomes do not differ between patients with proximal UCDs and those with distal UCDs. Factors other than hyperammonemia may contribute to poor neurocognitive outcome in the distal UCDs.
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Affiliation(s)
- Nicholas Ah Mew
- Center for Genetic Medicine and Center for Clinical and Community Research, Children's National Medical Center, Department of Pediatrics, The George Washington University, Washington, DC 20010, USA
| | - Lauren Krivitzky
- Neuropsychology & Assessment, Department of Child and Adolescent Psychiatry and Behavioral Sciences, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Robert McCarter
- Center for Genetic Medicine and Center for Clinical and Community Research, Children's National Medical Center, Department of Pediatrics, The George Washington University, Washington, DC 20010, USA
| | - Mark Batshaw
- Center for Genetic Medicine and Center for Clinical and Community Research, Children's National Medical Center, Department of Pediatrics, The George Washington University, Washington, DC 20010, USA
| | - Mendel Tuchman
- Center for Genetic Medicine and Center for Clinical and Community Research, Children's National Medical Center, Department of Pediatrics, The George Washington University, Washington, DC 20010, USA
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Mitchell S, Welch-Burke T, Dumitrescu L, Lomenick JP, Murdock DG, Crawford DC, Summar M. Peptide tyrosine tyrosine levels are increased in patients with urea cycle disorders. Mol Genet Metab 2012; 106:39-42. [PMID: 22459207 PMCID: PMC3336020 DOI: 10.1016/j.ymgme.2012.02.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Accepted: 02/14/2012] [Indexed: 11/25/2022]
Abstract
Nutritional management is essential for patients with inborn errors of metabolism, such as urea cycle disorders (UCDs). Lack of appetite is common in these patients and can lead to underconsumption of calories, catabolism, and subsequently loss of metabolic control. The etiology of anorexia in these patients is largely unexplored. The neuroendocrine hormone peptide tyrosine tyrosine (PYY), secreted postprandially from endocrine cells of the ileum and colon, induces feelings of satiety and decreases food intake. While plasma PYY levels have been characterized in a number of populations, they have not been examined in UCD patients. In a retrospective study, plasma PYY concentrations were measured in UCD (n=42) patients and controls (n=28) via an ELISA to determine if levels of this anorexigenic hormone are altered in this patient population. Median PYY levels were significantly higher in UCD patients compared to controls (p=3.5×10(-5)). Body mass index was significantly associated with increased PYY levels in controls (p=0.02), while UCD diagnosis subtype was associated with PYY levels (p=1×10(-3)) in cases. Median PYY levels were significantly lower in ornithine carbamoyltransferase deficient patients compared with all other UCD subtypes (p=9×10(-3)), but significantly higher compared to controls (p=1.6×10(-3)). Overall, this study demonstrates that UCD cases have increased PYY levels compared to controls, suggesting that regulation of PYY may be altered in these patients. These observations may lead to a better understanding of the development of anorexia in UCD patients.
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Affiliation(s)
- Sabrina Mitchell
- Center for Human Genetics Research, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Choi DE, Lee KW, Shin YT, Na KR. Hyperammonemia in a patient with late-onset ornithine carbamoyltransferase deficiency. J Korean Med Sci 2012; 27:556-9. [PMID: 22563224 PMCID: PMC3342550 DOI: 10.3346/jkms.2012.27.5.556] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 01/26/2012] [Indexed: 12/31/2022] Open
Abstract
Ornithine carbamoyltransferase (OTC) deficiency is a urea cycle disorder that causes the accumulation of ammonia, which can lead to encephalopathy. Adults presenting with hyperammonemia who are subsequently diagnosed with urea cycle disorders are rare. Herein, we report a case of a late-onset OTC deficient patient who was successfully treated with arginine, benzoate and hemodialysis. A 59-yr-old man was admitted to our hospital with progressive lethargy and confusion. Although hyperammonemia was suspected as the cause of the patient's mental changes, there was no evidence of chronic liver disease. A plasma amino acid and urine organic acid analysis revealed OTC deficiency. Despite the administration of a lactulose enema, the patient's serum ammonia level increased and he remained confused, leading us to initiate acute hemodialysis. After treatment with arginine, sodium benzoate and hemodialysis, the patient's serum ammonia level stabilized and his mental status returned to normal.
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Affiliation(s)
- Dae Eun Choi
- Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea
| | - Kang Wook Lee
- Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea
| | - Young Tai Shin
- Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea
| | - Ki Ryang Na
- Department of Internal Medicine, Chungnam National University Hospital, Daejeon, Korea
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Bireley WR, Van Hove JLK, Gallagher RC, Fenton LZ. Urea cycle disorders: brain MRI and neurological outcome. Pediatr Radiol 2012; 42:455-62. [PMID: 21989980 DOI: 10.1007/s00247-011-2253-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/17/2011] [Accepted: 08/22/2011] [Indexed: 01/09/2023]
Abstract
BACKGROUND Urea cycle disorders encompass several enzyme deficiencies that can result in cerebral damage, with a wide clinical spectrum from asymptomatic to severe. OBJECTIVE The goal of this study was to correlate brain MRI abnormalities in urea cycle disorders with clinical neurological sequelae to evaluate whether MRI abnormalities can assist in guiding difficult treatment decisions. MATERIALS AND METHODS We performed a retrospective chart review of patients with urea cycle disorders and symptomatic hyperammonemia. Brain MRI images were reviewed for abnormalities that correlated with severity of clinical neurological sequelae. RESULTS Our case series comprises six urea cycle disorder patients, five with ornithine transcarbamylase deficiency and one with citrullinemia type 1. The observed trend in distribution of brain MRI abnormalities as the severity of neurological sequelae increased was the peri-insular region first, extending into the frontal, parietal, temporal and, finally, the occipital lobes. There was thalamic restricted diffusion in three children with prolonged hyperammonemia. Prior to death, this site is typically reported to be spared in urea cycle disorders. CONCLUSION The pattern and extent of brain MRI abnormalities correlate with clinical neurological outcome in our case series. This suggests that brain MRI abnormalities may assist in determining prognosis and helping clinicians with subsequent treatment decisions.
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Affiliation(s)
- William R Bireley
- Department of Radiology, University of Colorado, 12631 E. 17th Ave., Aurora, CO 80045, USA.
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Diagnosis of ornithine transcarbamylase deficiency secondary to p.Leu301Phe mutation in an adult patient. Rev Neurol (Paris) 2012; 168:296-7. [DOI: 10.1016/j.neurol.2011.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 04/19/2011] [Accepted: 06/22/2011] [Indexed: 11/18/2022]
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