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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Zhang Q, Hao S, Hui L, Zheng L, Wang X, Feng X, Liu F, Chen X, Zhou B, Wang Y, Zhang C. [Genetic analysis and prenatal diagnosis for a Chinese pedigree affected with co-morbid Ornithine carbamoyl transferase deficiency and MECP2 duplication syndrome]. Zhonghua Yi Xue Yi Chuan Xue Za Zhi 2024; 41:306-311. [PMID: 38448019 DOI: 10.3760/cma.j.cn511374-20221202-00828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
OBJECTIVE To explore the genetic basis for a Chinese pedigree affected with co-morbid Ornithine carbamoyl transferase deficiency (OTCD) and MECP2 duplication syndrome. METHODS A proband who was admitted to the Neonatal Intensive Care Unit of Gansu Provincial Maternal and Child Health Care Hospital on December 19, 2017 was selected as the study subject. High-throughput sequencing and multiplex ligation-dependent probe amplification (MLPA) were carried out for her pedigree, and short tandem repeat-based linkage analysis and chromosome copy number variation sequencing (CNV-seq) were used for the prenatal diagnosis. RESULTS The proband, a 3-day-old female, was found to harbor heterozygous deletion of exons 7-9 of the OTC gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was classified as likely pathogenic (PVS1+PM2_Supporting+PP4). The proband was diagnosed with OTCD , which was in keeping with her acute encephalopathy and metabolic abnormalities (manifesting as hyperammonemia, decreased blood citrulline, and increased urine orotic acid). Prenatal diagnosis was carried out for the subsequent pregnancy. The fetus did not harbor the exons 7-9 deletion of the OTC gene, but was found to carry a duplication in Xq28 region (which encompassed the whole region of MECP2 duplication syndrome) and was positive for the SRY sequence. The same duplication was also found in the proband and her mother. Considering the possible existence of X-chromosome inactivation, the proband was diagnosed with two X-linked recessive disorders including OTCD and MECP2 duplication syndrome, and the fetus was determined as a male affected with the MECP2 duplication syndrome. CONCLUSION Discoveries of the pathogenic variants underlying the OTCD and MECP2 duplication syndrome have enabled clinical intervention, treatment, genetic counseling and prenatal diagnosis for this pedigree.
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Affiliation(s)
- Qinghua Zhang
- Medical Genetics Center, Gansu Provincial Maternal and Child Health Care Hospital (Gansu Provincial Central Hospital), Lanzhou, Gansu 730050, China.
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Siri B, Olivieri G, Lepri FR, Poms M, Goffredo BM, Commone A, Novelli A, Häberle J, Dionisi-Vici C. Father-to-daughter transmission in late-onset OTC deficiency: an underestimated mechanism of inheritance of an X-linked disease. Orphanet J Rare Dis 2024; 19:3. [PMID: 38167094 PMCID: PMC10763478 DOI: 10.1186/s13023-023-02997-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 12/13/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Ornithine Transcarbamylase Deficiency (OTCD) is an X-linked urea cycle disorder characterized by acute hyperammonemic episodes. Hemizygous males are usually affected by a severe/fatal neonatal-onset form or, less frequently, by a late-onset form with milder disease course, depending on the residual enzymatic activity. Hyperammonemia can occur any time during life and patients could remain non- or mis-diagnosed due to unspecific symptoms. In heterozygous females, clinical presentation varies based on the extent of X chromosome inactivation. Maternal transmission in X-linked disease is the rule, but in late-onset OTCD, due to the milder phenotype of affected males, paternal transmission to the females is possible. So far, father-to-daughter transmission of OTCD has been reported only in 4 Japanese families. RESULTS We identified in 2 Caucasian families, paternal transmission of late-onset OTCD with severe/fatal outcome in affected males and 1 heterozygous female. Furthermore, we have reassessed the pedigrees of other published reports in 7 additional families with evidence of father-to-daughter inheritance of OTCD, identifying and listing the family members for which this transmission occurred. CONCLUSIONS Our study highlights how the diagnosis and pedigree analysis of late-onset OTCD may represent a real challenge for clinicians. Therefore, the occurrence of paternal transmission in OTCD should not be underestimated, due to the relevant implications for disease inheritance and risk of recurrence.
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Affiliation(s)
- Barbara Siri
- Division of Metabolic Diseases and Hepatology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy.
- Department of Paediatrics, Città della Salute e della Scienza, OIRM, University of Turin, Turin, Italy.
| | - Giorgia Olivieri
- Division of Metabolic Diseases and Hepatology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Francesca Romana Lepri
- Translational Cytogenomics Research Unit, Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Martin Poms
- Division of Clinical Chemistry and Biochemistry and Children's Research Center, University Children's Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bianca Maria Goffredo
- Division of Metabolism and Metabolic Diseases Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anna Commone
- Division of Metabolic Diseases and Hepatology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Antonio Novelli
- Translational Cytogenomics Research Unit, Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Johannes Häberle
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Carlo Dionisi-Vici
- Division of Metabolic Diseases and Hepatology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
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Duff C, Alexander IE, Baruteau J. Gene therapy for urea cycle defects: An update from historical perspectives to future prospects. J Inherit Metab Dis 2024; 47:50-62. [PMID: 37026568 PMCID: PMC10953416 DOI: 10.1002/jimd.12609] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 04/08/2023]
Abstract
Urea cycle defects (UCDs) are severe inherited metabolic diseases with high unmet needs which present a permanent risk of hyperammonaemic decompensation and subsequent acute death or neurological sequelae, when treated with conventional dietetic and medical therapies. Liver transplantation is currently the only curative option, but has the potential to be supplanted by highly effective gene therapy interventions without the attendant need for life-long immunosuppression or limitations imposed by donor liver supply. Over the last three decades, pioneering genetic technologies have been explored to circumvent the consequences of UCDs, improve quality of life and long-term outcomes: adenoviral vectors, adeno-associated viral vectors, gene editing, genome integration and non-viral technology with messenger RNA. In this review, we present a summarised view of this historical path, which includes some seminal milestones of the gene therapy's epic. We provide an update about the state of the art of gene therapy technologies for UCDs and the current advantages and pitfalls driving future directions for research and development.
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Affiliation(s)
- Claire Duff
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child HealthUniversity College LondonLondonUK
| | - Ian E. Alexander
- Gene Therapy Research Unit, Children's Medical Research Institute, Faculty of Medicine and HealthThe University of Sydney and Sydney Children's Hospitals NetworkWestmeadNew South WalesAustralia
- Discipline of Child and Adolescent HealthThe University of SydneyWestmeadNew South WalesAustralia
| | - Julien Baruteau
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child HealthUniversity College LondonLondonUK
- National Institute of Health Research Great Ormond Street Biomedical Research CentreLondonUK
- Metabolic Medicine DepartmentGreat Ormond Street Hospital for Children NHS Foundation TrustLondonUK
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5
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Cunningham SC, van Dijk EB, Zhu E, Sugden M, Mandwie M, Siew S, Devanapalli B, Tolun AA, Klein A, Wilson L, Aryamanesh N, Gissen P, Baruteau J, Bhattacharya K, Alexander IE. Recapitulation of Skewed X-Inactivation in Female Ornithine Transcarbamylase-Deficient Primary Human Hepatocytes in the FRG Mouse: A Novel System for Developing Epigenetic Therapies. Hum Gene Ther 2023; 34:917-926. [PMID: 37350098 DOI: 10.1089/hum.2023.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023] Open
Abstract
Realization of the immense therapeutic potential of epigenetic editing requires development of clinically predictive model systems that faithfully recapitulate relevant aspects of the target disease pathophysiology. In female patients with ornithine transcarbamylase (OTC) deficiency, an X-linked condition, skewed inactivation of the X chromosome carrying the wild-type OTC allele is associated with increased disease severity. The majority of affected female patients can be managed medically, but a proportion require liver transplantation. With rapid development of epigenetic editing technology, reactivation of silenced wild-type OTC alleles is becoming an increasingly plausible therapeutic approach. Toward this end, privileged access to explanted diseased livers from two affected female infants provided the opportunity to explore whether engraftment and expansion of dissociated patient-derived hepatocytes in the FRG mouse might produce a relevant model for evaluation of epigenetic interventions. Hepatocytes from both infants were successfully used to generate chimeric mouse-human livers, in which clusters of primary human hepatocytes were either OTC positive or negative by immunohistochemistry (IHC), consistent with clonal expansion from individual hepatocytes in which the mutant or wild-type OTC allele was inactivated, respectively. Enumeration of the proportion of OTC-positive or -negative human hepatocyte clusters was consistent with dramatic skewing in one infant and minimal to modest skewing in the other. Importantly, IHC and fluorescence-activated cell sorting analysis of intact and dissociated liver samples from both infants showed qualitatively similar patterns, confirming that the chimeric mouse-human liver model recapitulated the native state in each infant. Also of importance was the induction of a treatable metabolic phenotype, orotic aciduria, in mice, which correlated with the presence of clonally expanded OTC-negative primary human hepatocytes. We are currently using this unique model to explore CRISPR-dCas9-based epigenetic targeting strategies in combination with efficient adeno-associated virus (AAV) gene delivery to reactivate the silenced functional OTC gene on the inactive X chromosome.
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Affiliation(s)
- Sharon C Cunningham
- Gene Therapy Research Unit, Faculty of Medicine and Health, Children's Medical Research Institute, The University of Sydney and Sydney Children's Hospitals Network, Westmead, Australia
| | - Eva B van Dijk
- Gene Therapy Research Unit, Faculty of Medicine and Health, Children's Medical Research Institute, The University of Sydney and Sydney Children's Hospitals Network, Westmead, Australia
| | - Erhua Zhu
- Gene Therapy Research Unit, Faculty of Medicine and Health, Children's Medical Research Institute, The University of Sydney and Sydney Children's Hospitals Network, Westmead, Australia
| | - Maya Sugden
- Gene Therapy Research Unit, Faculty of Medicine and Health, Children's Medical Research Institute, The University of Sydney and Sydney Children's Hospitals Network, Westmead, Australia
| | - Mawj Mandwie
- Gene Therapy Research Unit, Faculty of Medicine and Health, Children's Medical Research Institute, The University of Sydney and Sydney Children's Hospitals Network, Westmead, Australia
| | - Susan Siew
- Department of Gastroenterology, James Fairfax Institute of Paediatric Nutrition, Sydney Children's Hospitals Network, Westmead, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, Australia
| | - Beena Devanapalli
- NSW Biochemical Genetics Service, The Children's Hospital at Westmead, Westmead, Australia
| | - Adviye Ayper Tolun
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, Australia
- NSW Biochemical Genetics Service, The Children's Hospital at Westmead, Westmead, Australia
| | - Anne Klein
- Australian e-Health Research Centre, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Sydney, Australia
| | - Laurence Wilson
- Australian e-Health Research Centre, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Sydney, Australia
- Department of Biomedical Sciences, Macquarie University, Macquarie Park, Australia
| | - Nader Aryamanesh
- Embryology Research Unit, Bioinformatics Group, Children's Medical Research Institute, University of Sydney, Westmead, Australia
| | - Paul Gissen
- National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, University College London, London, United Kingdom
| | - Julien Baruteau
- National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, University College London, London, United Kingdom
| | - Kaustuv Bhattacharya
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, Australia
- Genetic Metabolic Disorders Service, The Children's Hospital at Westmead, Sydney, Australia
| | - Ian E Alexander
- Gene Therapy Research Unit, Faculty of Medicine and Health, Children's Medical Research Institute, The University of Sydney and Sydney Children's Hospitals Network, Westmead, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, Australia
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Belanger AJ, Gefteas E, Przybylska M, Geller S, Anarat-Cappillino G, Kloss A, Yew NS. Excretion of excess nitrogen and increased survival by loss of SLC6A19 in a mouse model of ornithine transcarbamylase deficiency. J Inherit Metab Dis 2023; 46:55-65. [PMID: 36220785 DOI: 10.1002/jimd.12568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/28/2022] [Accepted: 10/11/2022] [Indexed: 01/19/2023]
Abstract
Protein catabolism ultimately yields toxic ammonia, which must be converted to urea by the liver for renal excretion. In extrahepatic tissues, ammonia is temporarily converted primarily to glutamine for subsequent hepatic extraction. Urea cycle disorders (UCDs) are inborn errors of metabolism causing impaired ureagenesis, leading to neurotoxic accumulation of ammonia and brain glutamine. Treatment includes dietary protein restriction and oral "ammonia scavengers." These scavengers chemically combine with glutamine and glycine to yield excretable products, creating an alternate pathway of waste nitrogen disposal. The amino acid transporter SLC6A19 is responsible for >95% of absorption and reabsorption of free neutral amino acids in the small intestine and kidney, respectively. Genetic SLC6A19 deficiency causes massive neutral aminoaciduria but is typically benign. We hypothesized that inhibiting SLC6A19 would open a novel and effective alternate pathway of waste nitrogen disposal. To test this, we crossed SLC6A19 knockout (KO) mice with spfash mice, a model of ornithine transcarbamylase (OTC) deficiency. Loss of SLC6A19 in spfash mice normalized plasma ammonia and brain glutamine and increased median survival in response to a high protein diet from 7 to 97 days. While induced excretion of amino acid nitrogen is likely the primary therapeutic mechanism, reduced intestinal absorption of dietary free amino acids, and decreased muscle protein turnover due to loss of SLC6A19 may also play a role. In summary, the results suggest that SLC6A19 inhibition represents a promising approach to treating UCDs and related aminoacidopathies.
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Affiliation(s)
| | | | | | - Sarah Geller
- Rare & Neurologic Diseases, Sanofi, Cambridge, USA
| | | | - Alla Kloss
- Rare & Neurologic Diseases, Sanofi, Cambridge, USA
| | - Nelson S Yew
- Rare & Neurologic Diseases, Sanofi, Cambridge, USA
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8
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Iijima H, Kubota M. A simple screening method for heterozygous female patients with ornithine transcarbamylase deficiency. Mol Genet Metab 2022; 137:301-307. [PMID: 36252454 DOI: 10.1016/j.ymgme.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/08/2022] [Accepted: 10/08/2022] [Indexed: 11/24/2022]
Abstract
Ornithine transcarbamylase deficiency (OTCD), caused by X-linked OTC mutations, is characterized by life-threatening hyperammonemia. Heterozygous female patients are often asymptomatic and usually have milder disease than affected male patients, but can have higher morbidity and mortality rates if the disease progresses prior to diagnosis. Our purpose was to establish a screening method for female heterozygotes with OTCD. We retrospectively identified female patients who underwent plasma amino acid analysis at the National Center for Child Health and Development, using data from electronic medical records from March 2002 to September 2021. We extracted patient age, medical history, and biochemical data, including plasma amino acid levels. Patients were categorized into several groups according to their underlying diseases; those with underlying diseases that could potentially affect plasma amino acid levels, such as mitochondrial disease or short bowel syndrome, were excluded, except for untreated OTCD. Biochemical values were compared between OTCD patients and others using the Mann-Whitney U test. The receiver operator characteristic analysis was performed to assess the diagnostic capability for detecting OTCD in each subject. For patients with multiple test data, the most recent of the measurement dates was used in the analysis. The data sets of 976 patients were included. There were significant differences in values of glutamine, citrulline, arginine, and ammonia, but the diagnostic capacity of each alone was inadequate. By contrast, the (glutamine + glycine)/(citrulline + arginine) ratio was appropriate for discriminating heterozygous female patients with OTCD, with a sensitivity of 100% and specificity of 98.6% when the cutoff level was 15.8; the AUC for this discrimination was 0.996 (95% confidence interval, 0.992 to 1.000). These findings could help identify heterozygous female patients with OTCD before the onset of clinical disease.
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Affiliation(s)
- Hiroyuki Iijima
- Department of General Pediatrics and Interdisciplinary Medicine, National Center for Child Health and Development, Tokyo, Japan.
| | - Mitsuru Kubota
- Department of General Pediatrics and Interdisciplinary Medicine, National Center for Child Health and Development, Tokyo, Japan
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9
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Knerr I, Cassiman D. Ornithine transcarbamylase deficiency: A diagnostic odyssey. J Inherit Metab Dis 2022; 45:661-662. [PMID: 35734906 PMCID: PMC9541173 DOI: 10.1002/jimd.12530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/22/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Ina Knerr
- National Centre for Inherited Metabolic DisordersChildren's Health Ireland (CHI) at Temple StreetDublinRepublic of Ireland
- University College Dublin (UCD)UCD School of MedicineDublinRepublic of Ireland
| | - David Cassiman
- Department of Gastroenterology‐Hepatology and Metabolic CenterUniversity Hospital LeuvenLeuvenBelgium
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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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11
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Santamaria R, Ballester M, Garcia-Llorens G, Martinez F, Blazquez M, Ribes-Koninckx C, Castell JV, Wuestefeld T, Bort R. Derivation of healthy hepatocyte-like cells from a female patient with ornithine transcarbamylase deficiency through X-inactivation selection. Sci Rep 2022; 12:2308. [PMID: 35145162 PMCID: PMC8831560 DOI: 10.1038/s41598-022-06184-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 01/18/2022] [Indexed: 11/09/2022] Open
Abstract
Autologous cell replacement therapy for inherited metabolic disorders requires the correction of the underlying genetic mutation in patient's cells. An unexplored alternative for females affected from X-linked diseases is the clonal selection of cells randomly silencing the X-chromosome containing the mutant allele, without in vivo or ex vivo genome editing. In this report, we have isolated dermal fibroblasts from a female patient affected of ornithine transcarbamylase deficiency and obtained clones based on inactivation status of either maternally or paternally inherited X chromosome, followed by differentiation to hepatocytes. Hepatocyte-like cells derived from these clones display indistinct features characteristic of hepatocytes, but express either the mutant or wild type OTC allele depending on X-inactivation pattern. When clonally derived hepatocyte-like cells were transplanted into FRG® KO mice, they were able to colonize the liver and recapitulate OTC-dependent phenotype conditioned by X-chromosome inactivation pattern. This approach opens new strategies for cell therapy of X-linked metabolic diseases and experimental in vitro models for drug development for such diseases.
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Affiliation(s)
- Ramon Santamaria
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
| | - Maria Ballester
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
| | - Guillem Garcia-Llorens
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Biochemistry and Molecular Biology Department, Universidad de Valencia, Valencia, Spain
| | - Francisco Martinez
- Genetics Unit, Instituto de Investigación Sanitaria La Fe, Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain
| | - Marina Blazquez
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
| | - Carmen Ribes-Koninckx
- Coeliac Disease and Inmunopathology Research Unit, Instituto de Investigación Sanitaria La Fe, Pediatric Gastroenterology, Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain
| | - Jose V Castell
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Biochemistry and Molecular Biology Department, Universidad de Valencia, Valencia, Spain
| | - Torsten Wuestefeld
- Laboratory for In Vivo Genetics & Gene Therapy, Genome Institute of Singapore, A*STAR & National Cancer Centre Singapore, School of Biological Science, SingHealth & Adj. Ass.-Prof. Nanyang Technological University, 60 Biopolis Street, #02-01 Genome, Singapore, 138672, Singapore
| | - Roque Bort
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain.
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12
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Ozdemir Y, Cag M, Gul S, Yüksel Z, Ergoren MC. In Silico Analysis of a De Novo OTC Variant as a Cause of Ornithine Transcarbamylase Deficiency. Appl Immunohistochem Mol Morphol 2022; 30:153-156. [PMID: 34670952 DOI: 10.1097/pai.0000000000000979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 09/06/2021] [Indexed: 11/25/2022]
Abstract
Ornithine transcarbamylase deficiency (OTCD) is the most common X-linked hereditary disorder of urea cycle disorders that is caused by neonatal hyperammonemia. OTC gene sequence variations are common causes of OTCD. The current study presents a 28-month-old baby girl proband with phenotypical characteristics of OTCD such as irritability, somnolence, intermittent vomiting, and high levels of serum ammonium. Whole-exome sequencing revealed a de novo c.275G>A p.(Arg92Gln) variant within the OTC gene. In silico analysis revealed a possible differential affinity between wild-type and mutant OTCase, while Arg92Gln decreases the binding ability of OTCase to the substrate, which can disrupt the urea cycle and explains the molecular pathogenicity of clinical hyperammonemia. In light of the fact that the genotype and phenotype correlation of OTCD is still uncertain, the present in silico analysis outcome can enhance our knowledge on this complicated, rare, and severe genetic disorder.
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Affiliation(s)
- Yesim Ozdemir
- Medical Genetics Department, Medical Faculty, Uskudar University
| | - Murat Cag
- Generel Surgery Department, Memorial Bahcelievler Hospital, Istanbul, Turkey
| | - Seref Gul
- Department of Chemical and Biological Engineering, Faculty of Engineering, Koc University
| | - Zafer Yüksel
- Human Genetics, Bioscientia GmbH, Ingelheim, Germany
| | - Mahmut C Ergoren
- Department of Medical Genetics, Faculty of Medicine, Near East University
- DESAM Insitute, Near East University, Nicosia, Cyprus
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13
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Durer S, Durer C, Hoilat GJ. Adult-onset ornithine transcarbamylase deficiency as a rare cause of fatal hyperammonaemia. Lancet 2021; 398:e11. [PMID: 34454677 DOI: 10.1016/s0140-6736(21)01606-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/25/2021] [Accepted: 07/06/2021] [Indexed: 11/17/2022]
Affiliation(s)
- Seren Durer
- Department of Internal Medicine, State University of New York Upstate Medical University Hospital, Syracuse, NY, USA.
| | - Ceren Durer
- Department of Internal Medicine, State University of New York Upstate Medical University Hospital, Syracuse, NY, USA
| | - Gilles Jadd Hoilat
- Department of Internal Medicine, State University of New York Upstate Medical University Hospital, Syracuse, NY, USA
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14
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Lopes‐Marques M, Pacheco AR, Peixoto MJ, Cardoso AR, Serrano C, Amorim A, Prata MJ, Cooper DN, Azevedo L. Common polymorphic OTC variants can act as genetic modifiers of enzymatic activity. Hum Mutat 2021; 42:978-989. [PMID: 34015158 PMCID: PMC8362079 DOI: 10.1002/humu.24221] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 05/05/2021] [Accepted: 05/18/2021] [Indexed: 12/24/2022]
Abstract
Understanding the role of common polymorphisms in modulating the clinical phenotype when they co‐occur with a disease‐causing lesion is of critical importance in medical genetics. We explored the impact of apparently neutral common polymorphisms, using the gene encoding the urea cycle enzyme, ornithine transcarbamylase (OTC), as a model system. Distinct combinations of genetic backgrounds embracing two missense polymorphisms were created in cis with the pathogenic p.Arg40His replacement. In vitro enzymatic assays revealed that the polymorphic variants were able to modulate OTC activity both in the presence or absence of the pathogenic lesion. First, we found that the combination of the minor alleles of polymorphisms p.Lys46Arg and p.Gln270Arg significantly enhanced enzymatic activity in the wild‐type protein. Second, enzymatic assays revealed that the minor allele of the p.Gln270Arg polymorphism was capable of ameliorating OTC activity when combined in cis with the pathogenic p.Arg40His replacement. Structural analysis predicted that the minor allele of the p.Gln270Arg polymorphism would serve to stabilize the OTC wild‐type protein, thereby corroborating the results of the experimental assays. Our findings demonstrate the potential importance of cis‐interactions between common polymorphic variants and pathogenic missense mutations and illustrate how standing genetic variation can modulate protein function.
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Affiliation(s)
- Mónica Lopes‐Marques
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - Ana Rita Pacheco
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
| | - Maria João Peixoto
- ICVS‐ Life and Health Sciences Research Institute, School of MedicineUniversity of MinhoBragaPortugal
- ICVS/3B's‐PT Government Associate LaboratoryBragaGuimarãesPortugal
| | - Ana Rita Cardoso
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - Catarina Serrano
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - António Amorim
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - Maria João Prata
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
| | - David N. Cooper
- Institute of Medical Genetics; School of MedicineCardiff UniversityCardiffUK
| | - Luísa Azevedo
- i3S‐Instituto de Investigação e Inovação em Saúde, Population Genetics and Evolution GroupUniversidade do PortoPortoPortugal
- IPATIMUP‐Institute of Molecular Pathology and Immunology, Population Genetics and Evolution GroupUniversity of PortoPortoPortugal
- Faculty of Sciences, Department of BiologyUniversity of PortoPortoPortugal
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15
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Sugahara G, Yamasaki C, Yanagi A, Furukawa S, Ogawa Y, Fukuda A, Enosawa S, Umezawa A, Ishida Y, Tateno C. Humanized liver mouse model with transplanted human hepatocytes from patients with ornithine transcarbamylase deficiency. J Inherit Metab Dis 2021; 44:618-628. [PMID: 33336822 PMCID: PMC8247293 DOI: 10.1002/jimd.12347] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 12/10/2020] [Accepted: 12/16/2020] [Indexed: 12/20/2022]
Abstract
Ornithine transcarbamylase deficiency (OTCD) is a metabolic and genetic disease caused by dysfunction of the hepatocytic urea cycle. To develop new drugs or therapies for OTCD, it is ideal to use models that are more closely related to human metabolism and pathology. Primary human hepatocytes (HHs) isolated from two patients (a 6-month-old boy and a 5-year-old girl) and a healthy donor were transplanted into host mice (hemi-, hetero-OTCD mice, and control mice, respectively). HHs were isolated from these mice and used for serial transplantation into the next host mouse or for in vitro experiments. Histological, biochemical, and enzyme activity analyses were performed. Cultured HHs were treated with ammonium chloride or therapeutic drugs. Replacement rates exceeded 80% after serial transplantation in both OTCD mice. These highly humanized OTCD mice showed characteristics similar to OTCD patients that included increased blood ammonia levels and urine orotic acid levels enhanced by allopurinol. Hemi-OTCD mice showed defects in OTC expression and significantly low enzymatic activities, while hetero-OTCD mice showed residual OTC expression and activities. A reduction in ammonium metabolism was observed in cultured HHs from OTCD mice, and treatment with the therapeutic drug reduced the ammonia levels in the culture medium. In conclusion, we established in vivo OTC mouse models with hemi- and hetero-patient HHs. HHs isolated from the mice were useful as an in vitro model of OTCD. These OTC models could be a source of valuable patient-derived hepatocytes that would enable large scale and reproducible experiments using the same donor.
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Affiliation(s)
- Go Sugahara
- Research and Development DepartmentPhoenixBio Co., LtdHigashi‐HiroshimaJapan
| | - Chihiro Yamasaki
- Research and Development DepartmentPhoenixBio Co., LtdHigashi‐HiroshimaJapan
| | - Ami Yanagi
- Research and Development DepartmentPhoenixBio Co., LtdHigashi‐HiroshimaJapan
| | - Suzue Furukawa
- Research and Development DepartmentPhoenixBio Co., LtdHigashi‐HiroshimaJapan
| | - Yuko Ogawa
- Research and Development DepartmentPhoenixBio Co., LtdHigashi‐HiroshimaJapan
| | - Akinari Fukuda
- National Center for Child Health and DevelopmentTokyoJapan
| | - Shin Enosawa
- Division for Advanced Medical SciencesNational Center for Child Health and DevelopmentTokyoJapan
| | - Akihiro Umezawa
- Regenerative MedicineNational Center for Child Health and DevelopmentTokyoJapan
| | - Yuji Ishida
- Research and Development DepartmentPhoenixBio Co., LtdHigashi‐HiroshimaJapan
- Research Center for Hepatology and GastroenterologyHiroshima UniversityHiroshimaJapan
| | - Chise Tateno
- Research and Development DepartmentPhoenixBio Co., LtdHigashi‐HiroshimaJapan
- Research Center for Hepatology and GastroenterologyHiroshima UniversityHiroshimaJapan
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16
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Division of Genetics and Metabolism, Child Diseases and Health Care Branch, Chinese Association for Maternal and Child Health. [Consensus on diagnosis and treatment of ornithine trans-carbamylase deficiency]. Zhejiang Da Xue Xue Bao Yi Xue Ban 2020; 49:539-547. [PMID: 33210478 PMCID: PMC8800749 DOI: 10.3785/j.issn.1008-9292.2020.04.11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/15/2020] [Indexed: 12/11/2022]
Abstract
Ornithine transcarbamylase deficiency(OTCD)is a most common ornithine cycle (urea cycle) disorder. It is a X-link inherited disorder caused by OTC gene mutation that in turn leads to reduction or loss of OTC enzyme activity. Its onset time is related to the lack of enzyme activity. Patients with neonatal onset usually have complete absence of OTC enzyme activity, which is mainly associated with male semi-zygotic mutations; and the disease progresses rapidly with high mortality rates. Patients with late onset vary in onset age and clinical manifestations, and the course of disease can be progressive or intermittent. The acute attack mainly manifests neuropsychiatric symptoms accompanied by digestive symptoms like liver function damage or even acute liver failure. Elevated blood ammonia is the main biochemical indicator of OTCD patients. Increased glutamine, decreased citrulline in blood, and increased orotic acid in urine are typical clinical manifestations for OTCD patients. Genetic testing of OTC gene is important for OTCD diagnosis. The goal of treatment is to minimize the neurological damage caused by hyperammonemia while ensuring the nutritional needs for patient development. For patients with poor response to medication and diet, liver transplantation is recommended under the condition of stable metabolic state and absence of severe neurological damage. During long-term treatment, physical growth indicators, nutrition status, liver function, blood ammonia and amino acids should be regularly monitored. This consensus aims to standardize the diagnosis and treatment of OTCD, improve the prognosis, reduce the mortality and disability of patients.
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17
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Wang L, Yang Y, Breton C, Bell P, Li M, Zhang J, Che Y, Saveliev A, He Z, White J, Latshaw C, Xu C, McMenamin D, Yu H, Morizono H, Batshaw ML, Wilson JM. A mutation-independent CRISPR-Cas9-mediated gene targeting approach to treat a murine model of ornithine transcarbamylase deficiency. Sci Adv 2020; 6:eaax5701. [PMID: 32095520 PMCID: PMC7015695 DOI: 10.1126/sciadv.aax5701] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 09/30/2019] [Indexed: 02/05/2023]
Abstract
Ornithine transcarbamylase (OTC) deficiency is an X-linked urea cycle disorder associated with high mortality. Although a promising treatment for late-onset OTC deficiency, adeno-associated virus (AAV) neonatal gene therapy would only provide short-term therapeutic effects as the non-integrated genome gets lost during hepatocyte proliferation. CRISPR-Cas9-mediated homology-directed repair can correct a G-to-A mutation in 10% of OTC alleles in the livers of newborn OTC spfash mice. However, an editing vector able to correct one mutation would not be applicable for patients carrying different OTC mutations, plus expression would not be fast enough to treat a hyperammonemia crisis. Here, we describe a dual-AAV vector system that accomplishes rapid short-term expression from a non-integrated minigene and long-term expression from the site-specific integration of this minigene without any selective growth advantage for OTC-positive cells in newborns. This CRISPR-Cas9 gene-targeting approach may be applicable to all patients with OTC deficiency, irrespective of mutation and/or clinical state.
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Affiliation(s)
- Lili Wang
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yang Yang
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Camilo Breton
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Peter Bell
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mingyao Li
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jia Zhang
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yan Che
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alexei Saveliev
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Zhenning He
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John White
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Caitlin Latshaw
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Chenyu Xu
- Center for Genetic Medicine Research, Children’s Research Institute, Children’s National Hospital, Washington, DC 20010, USA
| | - Deirdre McMenamin
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongwei Yu
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children’s Research Institute, Children’s National Hospital, Washington, DC 20010, USA
| | - Mark L. Batshaw
- Center for Genetic Medicine Research, Children’s Research Institute, Children’s National Hospital, Washington, DC 20010, USA
| | - James M. Wilson
- Gene Therapy Program, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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18
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Olga S, Natalia S, Igor B, Alena C, Ekaterina Z, Oksana R, Zhanna M, Nadezhda S, Aleksander P. A novel splice site mutation in OTC gene of a female with ornithine transcarbamylase deficiency and her asymptomatic mosaic father. J Genet 2020; 99:29. [PMID: 32482918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ornithine transcarbamylase deficiency is an X-linked disease with a wide range of clinical severity and manifestation age both in males and females. Here, we describe a case which is caused by a novel c.78-1G[A splice site mutation, which on mRNA level leads to a 1-bp deletion and a frameshift (c.78delG (p.C27Vfs*11)) in OTC exon 2 in a young girl. The same mutation has been detected in a mosaicstate in her asymptomatic father.
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Affiliation(s)
- Shchagina Olga
- Research Centre for Medical Genetics, Moscow 115522, Russia. ,
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19
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Allegri G, Deplazes S, Rimann N, Causton B, Scherer T, Leff JW, Diez-Fernandez C, Klimovskaia A, Fingerhut R, Krijt J, Kožich V, Nuoffer JM, Grisch-Chan HM, Thöny B, Häberle J. Comprehensive characterization of ureagenesis in the spf ash mouse, a model of human ornithine transcarbamylase deficiency, reveals age-dependency of ammonia detoxification. J Inherit Metab Dis 2019; 42:1064-1076. [PMID: 30714172 DOI: 10.1002/jimd.12068] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/30/2019] [Indexed: 12/24/2022]
Abstract
The most common ureagenesis defect is X-linked ornithine transcarbamylase (OTC) deficiency which is a main target for novel therapeutic interventions. The spf ash mouse model carries a variant (c.386G>A, p.Arg129His) that is also found in patients. Male spf ash mice have a mild biochemical phenotype with low OTC activity (5%-10% of wild-type), resulting in elevated urinary orotic acid but no hyperammonemia. We recently established a dried blood spot method for in vivo quantification of ureagenesis by Gas chromatography-mass spectrometry (GC-MS) using stable isotopes. Here, we applied this assay to wild-type and spf ash mice to assess ureagenesis at different ages. Unexpectedly, we found an age-dependency with a higher capacity for ammonia detoxification in young mice after weaning. A parallel pattern was observed for carbamoylphosphate synthetase 1 and OTC enzyme expression and activities, which may act as pacemaker of this ammonia detoxification pathway. Moreover, high ureagenesis in younger mice was accompanied by elevated periportal expression of hepatic glutamine synthetase, another main enzyme required for ammonia detoxification. These observations led us to perform a more extensive analysis of the spf ash mouse in comparison to the wild-type, including characterization of the corresponding metabolites, enzyme activities in the liver and plasma and the gut microbiota. In conclusion, the comprehensive enzymatic and metabolic analysis of ureagenesis performed in the presented depth was only possible in animals. Our findings suggest such analyses being essential when using the mouse as a model and revealed age-dependent activity of ammonia detoxification.
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Affiliation(s)
- Gabriella Allegri
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Sereina Deplazes
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Nicole Rimann
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | | | - Tanja Scherer
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | | | - Carmen Diez-Fernandez
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Anna Klimovskaia
- Institute for Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Ralph Fingerhut
- Swiss Newborn Screening Laboratory, University Children's Hospital, Zurich, Switzerland
| | - Jakub Krijt
- Department of Pediatrics and Adolescent Medicine, Charles University-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Viktor Kožich
- Department of Pediatrics and Adolescent Medicine, Charles University-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Jean-Marc Nuoffer
- Department of Clinical Chemistry, Inselspital Bern, Bern, Switzerland
| | - Hiu M Grisch-Chan
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Beat Thöny
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
| | - Johannes Häberle
- Division of Metabolism and Children's Research Center (CRC), University Children's Hospital Zurich, Zurich, Switzerland
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Abstract
INTRODUCTION Ornithine transcarbamylase deficiency (OTCD) is a common metabolic disease of urea circulation disorder. We reported the clinical, brain imaging and genetic characteristics of 2 cases with OTCD. The patients' clinical features, novel gene mutations, cranial MR specific imaging changes and blood tandem mass spectrometry, and urine gas chromatography-mass spectrometry were, retrospectively, analyzed. PATIENT CONCERNS Patient 1 was a 1.6-year-old female. She was admitted to the hospital with 2-months history of general irritability and disturbance of consciousness for a day. Patient 2 was a 3.7-year-old female. She was admitted to the hospital due to decline of language ability and irritability for 5 days. Blood tandem mass spectrometry and urine gas chromatography-mass spectrometry showed uracil and orotate increased significantly in urine while amino acids in the urea cycle ring were in the normal range. The features of brain MRI are consistent with those of urea circulatory disorders. Gene detection showed 1 novel mutation in the OTC gene (c.658C>T) in patient 1 and, 1 novel mutation (c.298+2T>G) in the OTC gene in patient 2. DIAGNOSIS Combined with metabolic screening and gene detection, both patients were diagnosed with OTCD. INTERVENTIONS The patients' condition improved after following a low protein diet and receiving treatments for decreasing blood ammonia, energy supplement, correcting acid-base imbalance, and other symptomatic treatments. OUTCOMES After prompt symptomatic treatment, the consciousness and cognition of the children improved. Besides, liver function also improved significantly. CONCLUSIONS For patients with neurological symptoms and unexplained increase in transaminase and ammonia, OTCD should be considered as a possible diagnosis. Brain MRI can help the diagnosis of genetic metabolic encephalopathy and reflect the level of brain injury. Metabolic screening and genetic detection are helpful to make a confirmed diagnosis.
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Affiliation(s)
- Dan Yu
- Department of Pediatrics, West China Second University Hospital, Sichuan University
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education
| | - Guoyan Lu
- Department of Pediatrics, West China Second University Hospital, Sichuan University
| | - Rajah Mowshica
- West China School of Medicine, West China Hospital Sichuan University
| | - Yan Cheng
- Department of Radiology, West China Second University Hospital, Sichuan University, China
| | - Fumin Zhao
- Department of Radiology, West China Second University Hospital, Sichuan University, China
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21
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Abstract
Metabolic liver diseases are attractive gene therapy targets that necessitate reconstitution of enzymatic activity in functionally complex biochemical pathways. The levels of enzyme activity required in individual hepatocytes and the proportion of the hepatic cell mass that must be gene corrected for therapeutic benefit vary in a disease-dependent manner that is difficult to predict. While empirical evaluation is inevitably required, useful insights can nevertheless be gained from knowledge of disease pathophysiology and theoretical approaches such as mathematical modeling. Urea cycle defects provide an excellent example. Building on a previously described one-compartment model of the urea cycle, we have constructed a two-compartment model that can simulate liver-targeted gene therapy interventions using the computational program Mathematica. The model predicts that therapeutically effective reconstitution of ureagenesis will correlate most strongly with the proportion of the hepatic cell mass transduced rather than the level of enzyme-encoding transgene expression achieved in individual hepatocytes. Importantly, these predictions are supported by experimental data in mice and human genotype/phenotype correlations. The most notable example of the latter is ornithine transcarbamylase deficiency (X-linked) where impairment of ureagenesis in male and female patients is closely simulated by the one- and two-compartment models, respectively. Collectively, these observations support the practical value of mathematical modeling in evaluation of the disease-specific gene transfer challenges posed by complex metabolic phenotypes.
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Affiliation(s)
- Cindy Y Kok
- Gene Therapy Research Unit, Children's Medical Research Institute, Faculty of Medicine and Health and Sydney Children's Hospitals Network, The University of Sydney, Westmead, Australia
| | - Sharon C Cunningham
- Gene Therapy Research Unit, Children's Medical Research Institute, Faculty of Medicine and Health and Sydney Children's Hospitals Network, The University of Sydney, Westmead, Australia
| | - Philip W Kuchel
- School of Life and Environmental Sciences, The University of Sydney, Westmead, Australia
| | - Ian E Alexander
- Gene Therapy Research Unit, Children's Medical Research Institute, Faculty of Medicine and Health and Sydney Children's Hospitals Network, The University of Sydney, Westmead, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Westmead, Australia
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Abstract
A 52-year-old woman developed vomiting and disturbance of consciousness after consuming raw fish and sushi on a trip. A blood test showed hyperammonemia (310 μg/dL) with a normal liver function. She fell into a deep coma, and her serum ammonia level increased to 684 μg/dL. L-arginine was administered as a diagnostic treatment for urea cycle disorder (UCD) and serum ammonia, and her consciousness levels improved. She was diagnosed with ornithine transcarbamylase deficiency (OTCD) by analyses of plasma amino acids, urinary orotic acid, and the OTC gene mutation. UCD should be considered for patients with hyperammonemia without severe liver function abnormalities.
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Affiliation(s)
- Yudai Koya
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Michihiko Shibata
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Michio Senju
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Yuichi Honma
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Masaaki Hiura
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Masahiro Ishii
- Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Shirou Matsumoto
- Department of Pediatrics, Graduate School of Medical Sciences, Kumamoto University, Japan
| | - Masaru Harada
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
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23
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Ng HI, Sun LY, Zhu ZJ. Application of graft-derived cell-free DNA in ornithine transcarbamylase deficiency patient after living donor liver transplantation: Two case reports. Medicine (Baltimore) 2018; 97:e13843. [PMID: 30572553 PMCID: PMC6320025 DOI: 10.1097/md.0000000000013843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
RATIONALE Graft-derived-cell-free DNA (Gcf-DNA) in plasma was a promising biomarker to monitor graft-rejection after liver transplantation. However, little is known about the application of Gcf-DNA in living-donor-liver-transplantation (LDLT). PATIENTS CONCERN In this study, 2 patients diagnosed with Ornithine Transcarbamylase Deficiency (OTCD) were enrolled and indicated for LDLT. DIAGNOSES Two patients were genetically diagnosed with OTCD, and they suffered from recurrent and uncontrollable hyper-ammonemia and failed in accepting the normalized OTCD treatments, such as decreasing dietary nitrogen intake and increasing waste-nitrogen excretion. INTERVENTIONS LDLT was performed in the 2 patients uneventfully, and we collected circulating cell-free DNA from plasma in specific postoperative time points (day 1, day 7, day 14, day 30, day 60). Since both of the recipients were sex-mismatch with the donors, we measured Gcf-DNA through the Y-chromosome method and compared it with the routine liver function. OUTCOMES The result showed that Gcf-DNA had the similar discrimination of graft injury trend while compared to routine liver function. The follow-up showed these 2 patients' status is stable. LESSONS Applying Gcf-DNA to monitor graft injury in LDLT is promising, but still long term follow-up and more samples are needed for validation.
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Wang X, Yuan Y, Didelija IC, Mohammad MA, Marini JC. Ex Vivo Enteroids Recapitulate In Vivo Citrulline Production in Mice. J Nutr 2018; 148:1415-1420. [PMID: 30184221 PMCID: PMC6669957 DOI: 10.1093/jn/nxy126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 03/29/2018] [Accepted: 05/24/2018] [Indexed: 12/15/2022] Open
Abstract
Background The endogenous production of arginine relies on the synthesis of citrulline by enteral ornithine transcarbamylase (OTC). Mutations in the gene coding for this enzyme are the most frequent cause of urea cycle disorders. There is a lack of correlation between in vivo metabolic function and DNA sequence, transcript abundance, or in vitro enzyme activity. Objective The goal of the present work was to test the hypothesis that enteroids, a novel ex vivo model, are able to recapitulate the in vivo citrulline production of wild-type (WT) and mutant mice. Methods Six-week-old male WT and OTC-deficient mice [sparse fur and abnormal skin (spf-ash) mutation] were studied. Urea and citrulline fluxes were determined in vivo, and OTC abundance was measured in liver and gut tissue. Intestinal crypts were isolated and cultured to develop enteroids. Ex vivo citrulline production and OTC abundance were determined in these enteroids. Results Liver OTC abundance was lower (mean ± SE: 0.16 ± 0.01 compared with 1.85 ± 0.18 arbitrary units; P < 0.001) in spf-ash mice than in WT mice, but there was no difference in urea production. In gut tissue, OTC was barely detectable in mutant mice; despite this, a lower but substantial citrulline production (67 ± 3 compared with 167 ± 8 µmol · kg-1 · h-1; P < 0.001) was shown in the mutant mice. Enteroids recapitulated the in vivo findings of a very low OTC content accompanied by a reduced citrulline production (1.07 ± 0.20 compared with 4.64 ± 0.44 nmol · µg DNA-1 · d-1; P < 0.001). Conclusions Enteroids recapitulate in vivo citrulline production and offer the opportunity to study the regulation of citrulline production in a highly manipulable system.
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Affiliation(s)
- Xiaoying Wang
- USDA–Agricultural Research Service Children's Nutrition Research Center, Houston, TX
| | - Yang Yuan
- USDA–Agricultural Research Service Children's Nutrition Research Center, Houston, TX
| | - Inka C Didelija
- USDA–Agricultural Research Service Children's Nutrition Research Center, Houston, TX
| | - Mahmoud A Mohammad
- USDA–Agricultural Research Service Children's Nutrition Research Center, Houston, TX
| | - Juan C Marini
- USDA–Agricultural Research Service Children's Nutrition Research Center, Houston, TX
- Pediatric Critical Care Medicine, Department of Pediatrics, Baylor College of Medicine, Houston, TX
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Prieve MG, Harvie P, Monahan SD, Roy D, Li AG, Blevins TL, Paschal AE, Waldheim M, Bell EC, Galperin A, Ella-Menye JR, Houston ME. Targeted mRNA Therapy for Ornithine Transcarbamylase Deficiency. Mol Ther 2018; 26:801-813. [PMID: 29433939 PMCID: PMC5910669 DOI: 10.1016/j.ymthe.2017.12.024] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 12/21/2017] [Accepted: 12/28/2017] [Indexed: 11/18/2022] Open
Abstract
We describe a novel, two-nanoparticle mRNA delivery system and show that it is highly effective as a means of intracellular enzyme replacement therapy (i-ERT) using a murine model of ornithine transcarbamylase deficiency (OTCD). Our Hybrid mRNA Technology delivery system (HMT) comprises an inert lipid nanoparticle that protects the mRNA from nucleases in the blood as it distributes to the liver and a polymer micelle that targets hepatocytes and triggers endosomal release of mRNA. This results in high-level synthesis of the desired protein specifically in the liver. HMT delivery of human OTC mRNA normalizes plasma ammonia and urinary orotic acid levels, and leads to a prolonged survival benefit in the murine OTCD model. HMT represents a unique, non-viral mRNA delivery method that allows multi-dose, systemic administration for treatment of single-gene inherited metabolic diseases.
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Affiliation(s)
- Mary G Prieve
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA.
| | - Pierrot Harvie
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Sean D Monahan
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Debashish Roy
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Allen G Li
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Teri L Blevins
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Amber E Paschal
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Matt Waldheim
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Eric C Bell
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | - Anna Galperin
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
| | | | - Michael E Houston
- PhaseRx, Inc., 410 W. Harrison Street, Suite 300, Seattle, WA 98119, USA
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26
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Wilnai Y, Blumenfeld YJ, Cusmano K, Hintz SR, Alcorn D, Benitz WE, Berquist WE, Bernstein JA, Castillo RO, Concepcion W, Cowan TM, Cox KL, Lyell DJ, Esquivel CO, Homeyer M, Hudgins L, Hurwitz M, Palma JP, Schelley S, Akula VP, Summar ML, Enns GM. Prenatal treatment of ornithine transcarbamylase deficiency. Mol Genet Metab 2018; 123:297-300. [PMID: 29396029 DOI: 10.1016/j.ymgme.2018.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 01/13/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE OF STUDY Patients with neonatal urea cycle defects (UCDs) typically experience severe hyperammonemia during the first days of life, which results in serious neurological injury or death. Long-term prognosis despite optimal pharmacological and dietary therapy is still poor. The combination of intravenous sodium phenylacetate and sodium benzoate (Ammonul®) can eliminate nitrogen waste independent of the urea cycle. We report attempts to improve outcomes for males with severe ornithine transcarbamylase deficiency (OTCD), a severe X-linked condition, via prenatal intravenous administration of Ammonul and arginine to heterozygous carrier females of OTCD during labor. METHODS USED Two heterozygote OTCD mothers carrying male fetuses with a prenatal diagnosis of OTCD received intravenous Ammonul, arginine and dextrose-containing fluids shortly before birth. Maintenance Ammonul and arginine infusions and high-caloric enteral nutrition were started immediately after birth. Ammonul metabolites were measured in umbilical cord blood and the blood of the newborn immediately after delivery. Serial ammonia and biochemical analyses were performed following delivery. SUMMARY OF RESULTS Therapeutic concentrations of Ammonul metabolites were detected in umbilical cord and neonatal blood samples. Plasma ammonia and glutamine levels in the postnatal period were within the normal range. Peak ammonia levels in the first 24-48h were 53mcmol/l and 62mcmol/l respectively. The boys did not experience neurological sequelae secondary to hyperammonemia and received liver transplantation at ages 3months and 5months. The patients show normal development at ages 7 and 3years. CONCLUSION Prenatal treatment of mothers who harbor severe OTCD mutations and carry affected male fetuses with intravenous Ammonul and arginine, followed by immediate institution of maintenance infusions after delivery, results in therapeutic levels of benzoate and phenylacetate in the newborn at delivery and, in conjunction with high-caloric enteral nutrition, prevents acute hyperammonemia and neurological decompensation. Following initial medical management, early liver transplantation may improve developmental outcome.
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Affiliation(s)
- Yael Wilnai
- Department of Pediatrics, Stanford University, CA, USA
| | - Yair J Blumenfeld
- Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kristina Cusmano
- Department of Genetics and Metabolism, Children's National Medical Center, Washington, DC, USA
| | - Susan R Hintz
- Department of Pediatrics, Stanford University, CA, USA
| | | | | | | | | | - Ricardo O Castillo
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Stanford University, CA, USA
| | - Waldo Concepcion
- Division of Abdominal Transplantation, Stanford University, CA, USA
| | - Tina M Cowan
- Department of Pathology, Stanford University, CA, USA
| | - Kenneth L Cox
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Stanford University, CA, USA
| | - Deirdre J Lyell
- Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA, USA
| | | | | | | | - Melissa Hurwitz
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, Stanford University, CA, USA
| | | | | | | | - Marshall L Summar
- Department of Genetics and Metabolism, Children's National Medical Center, Washington, DC, USA
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Wang L, Bell P, Morizono H, He Z, Pumbo E, Yu H, White J, Batshaw ML, Wilson JM. AAV gene therapy corrects OTC deficiency and prevents liver fibrosis in aged OTC-knock out heterozygous mice. Mol Genet Metab 2017; 120:299-305. [PMID: 28283349 PMCID: PMC5423267 DOI: 10.1016/j.ymgme.2017.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/28/2017] [Accepted: 02/28/2017] [Indexed: 12/23/2022]
Abstract
Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder of the urea cycle. Hemizygous males and heterozygous females may experience life-threatening elevations of ammonia in blood and brain, leading to irreversible cognitive impairment, coma, and death. Recent evidence of acute liver failure and fibrosis/cirrhosis is also emerging in OTC-deficient patients. Here, we investigated the long-term consequences of abnormal ureagenesis in female mice heterozygous (Het) for a null mutation in the OTC gene. Two-month-old Het OTC knockout (KO) mice received a single dose of self-complementary adeno-associated virus (AAV) encoding a codon-optimized human OTC gene at 1×1010, 3×1010, or 1×1011 vector genome copies per mouse. We compared liver pathology from 18-month-old treated Het OTC-KO mice, age-matched untreated Het OTC-KO mice, and WT littermates, and assessed urinary orotic acid levels and vector genome copies in liver at 4, 10, and 16months following vector administration. Het OTC-KO female mice showed evidence of liver inflammation and the eventual development of significant fibrosis. Treatment with AAV gene therapy not only corrected the underlying metabolic abnormalities, but also prevented the development of liver fibrosis. Our study demonstrates that early treatment of OTC deficiency with gene therapy may prevent clinically relevant consequences of chronic liver damage from developing.
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Affiliation(s)
- Lili Wang
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, 125 S. 31st Street, Philadelphia, PA 19104, USA
| | - Peter Bell
- Gene Therapy Program, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 125 S. 31st Street, Philadelphia, PA 19104, USA
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children's Research Institute, Children's National Health System, 111 Michigan Ave., Washington, DC 20010, USA
| | - Zhenning He
- Gene Therapy Program, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 125 S. 31st Street, Philadelphia, PA 19104, USA
| | - Elena Pumbo
- Center for Genetic Medicine Research, Children's Research Institute, Children's National Health System, 111 Michigan Ave., Washington, DC 20010, USA
| | - Hongwei Yu
- Gene Therapy Program, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 125 S. 31st Street, Philadelphia, PA 19104, USA
| | - John White
- Gene Therapy Program, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 125 S. 31st Street, Philadelphia, PA 19104, USA
| | - Mark L Batshaw
- Center for Genetic Medicine Research, Children's Research Institute, Children's National Health System, 111 Michigan Ave., Washington, DC 20010, USA
| | - James M Wilson
- Gene Therapy Program, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, 125 S. 31st Street, Philadelphia, PA 19104, USA.
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28
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Beard L, Wymore E, Fenton L, Coughlin CR, Weisfeld-Adams JD. Lethal neonatal hyperammonemia in severe ornithine transcarbamylase (OTC) deficiency compounded by large hepatic portosystemic shunt. J Inherit Metab Dis 2017; 40:159-160. [PMID: 27832417 DOI: 10.1007/s10545-016-9985-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 09/15/2016] [Accepted: 09/19/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Lauren Beard
- Division of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.
| | - Erica Wymore
- Division of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Laura Fenton
- Division of Pediatric Radiology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Curtis R Coughlin
- Division of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - James D Weisfeld-Adams
- Division of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
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Abstract
We report a 3-year-old Saudi boy with recurrent episodes of vomiting, poor feeding, and altered mental status accompanied by an intermittent mild hyperammonemia, and a large elevation of urinary orotic acid. Sanger sequencing of the ornithine transcarbamylase (OTC) gene revealed a novel hemizygous deletion at the fourth nucleotide of intron 4 (c.386+4delT) in the proband and his asymptomatic mother. This novel mutation in the OTC gene is responsible for the late-onset phenotype of OTC deficiency.
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Affiliation(s)
- Sarar Mohamed
- Department of Pediatrics (39), College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia. E-mail.
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30
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Abstract
OBJECTIVE In Jane Austen's Pride and Prejudice, members of the Bennet family are either sensible or silly, and males are under-represented. This study searches for an underlying medical diagnosis that explains these features. DESIGN Very retrospective literature review. PARTICIPANTS Mrs Bennet, her five daughters (Jane, Elizabeth, Mary, Kitty and Lydia), her brother (Mr Gardiner) and her sister (Mrs Phillips). MAIN OUTCOME MEASURES Family tree and associated phenotypes METHODS The author read Pride and Prejudice. A Bennet family tree was constructed. The number of male and female descendants was analysed using a binomial model. For each character, evidence of behaviour was collected, and members of the Bennet family were categorised as either sensible or silly. RESULTS Males are under-represented in Mrs Bennet's family. Assuming an equal probability of male or female offspring, this reaches statistical significance (binomial model, P = 0.03). Approximately 50% of females in the family are silly. Silly behaviour is more prevalent during social gatherings. CONCLUSIONS The family tree suggests an X-linked genetic disorder, fatal in utero or in early life to affected males, explaining the paucity of male offspring. Female carriers survive, but with cognitive difficulties, explaining the approximate 50-50 distribution of sensible and silly females in the family. The exacerbation of silliness during social gatherings may suggest an effect of protein intake, raising suspicions of a disorder of protein metabolism. Ornithine transcarbamylase deficiency is one such condition. Unfortunately, there remain significant challenges in performing genetic testing on fictional characters, so definitive evidence remains elusive. Jane and Elizabeth Bennet do not show signs of the disorder. However, carriers may be asymptomatic; they should be offered genetic counselling before Bingley or Darcy offspring are considered.
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Affiliation(s)
- William Stern
- Department of Clinical and Experimental Epilepsy, NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, London, UK.
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31
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Tong W, Jin D, Sun J. [Report of a case with late-onset ornithine transcarbamylase deficiency with gas chromatography-mass spectrometry and DNA sequencing confirmation and literatures review]. Zhonghua Er Ke Za Zhi 2015; 53:366-369. [PMID: 26080667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVE To discuss the clinical characteristics, diagnosis and treatment management of ornithine transcarbamylase deficiency (OTCD). METHOD Data of the clinical diagnosis and treatment of a case with OTCD were analyzed, and the domestic and international literature was reviewed. RESULT (1) The case was a boy, 8 years old; and the initial symptoms were vomiting and reduced consciousness for a day after eating a lot of eggs as previous similar history. The level of blood ammonia was 2 500 µmol/L. The patient was treated with fasting, high-calorie fluid intravenous infusion, reducing blood ammonia. However, the disease further aggravated and the patient died due to brain hernia and central cardiovascular failure. Finally, he was confirmed as OTCD through urine testing by gas chromatography-mass spectrometry, plasma amino acid examination (plasma arginine and citrullineurine reduced, orotic acid raised) and genetic testing (OTC c.386G>A p. (Arg129His)). (2) Data of 55 case reports about diagnosis and treatment outcome including 65 OTCD cases' clinical data in domestic and abroad reports in nearly 5 years. Their ages ranged from 3 days to 49 years; the common symptoms were vomiting and encephalopathy; both urine tests were positive in 52 cases; pathogenic genes had less repeated loci and located at Xp21.1 in 42 cases detected by OTC gene test; all of which had gene mutation. CONCLUSION The acute onset OTCD begins with the symptoms of vomiting and unconsciousness, with rapid rise of blood ammonia level. OTCD may cause high mortality.
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Affiliation(s)
- Wenjia Tong
- Department of Pediatric Intensive Care Medicine, Anhui Province Children's Hospital, Hefei 230051, China
| | - Danqun Jin
- Department of Pediatric Intensive Care Medicine, Anhui Province Children's Hospital, Hefei 230051, China;
| | - Jingmin Sun
- Department of Pediatric Intensive Care Medicine, Anhui Province Children's Hospital, Hefei 230051, China
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Sprouse C, King J, Helman G, Pacheco-Colón I, Shattuck K, Breeden A, Seltzer R, VanMeter JW, Gropman AL. Investigating neurological deficits in carriers and affected patients with ornithine transcarbamylase deficiency. Mol Genet Metab 2014; 113:136-41. [PMID: 24881970 PMCID: PMC4458385 DOI: 10.1016/j.ymgme.2014.05.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Urea cycle disorders are caused by dysfunction in any of the six enzymes and two transport proteins involved in urea biosynthesis. Our study focuses on ornithine transcarbamylase deficiency (OTCD), an X-linked disorder that results in a dysfunctional mitochondrial enzyme, which prevents the synthesis of citrulline from carbamoyl phosphate and ornithine. This enzyme deficiency can lead to hyperammonemic episodes and severe cerebral edema. The objective of this study was to use a cognitive battery to expose the cognitive deficits in asymptomatic carriers of OTCD. MATERIALS AND METHODS In total, 81 participants were recruited as part of a larger urea cycle disorder imaging consortium study. There were 25 symptomatic participants (18 female, 7 male, 25.6 year s ± 12.72 years), 20 asymptomatic participants (20 female, 0 male, 37.6 years ± 15.19 years), and 36 healthy control participants (21 female, 15 male, 29.8 years ± 13.39 years). All participants gave informed consent to participate and were then given neurocognitive batteries with standard scores and T scores recorded. RESULTS When stratified by symptomatic participant, asymptomatic carrier, and control, the results showed significant differences in measures of executive function (e.g. CTMT and Stroop) and motor ability (Purdue Assembly) between all groups tested. Simple attention, academic measures, language and non-verbal motor abilities showed no significant differences between asymptomatic carriers and control participants, however, there were significant differences between symptomatic and control participant performance in these measures. CONCLUSIONS In our study, asymptomatic carriers of OTCD showed no significant differences in cognitive function compared to control participants until they were cognitively challenged with fine motor tasks, measures of executive function, and measures of cognitive flexibility. This suggests that cognitive dysfunction is best measurable in asymptomatic carriers after they are cognitively challenged.
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Affiliation(s)
- Courtney Sprouse
- Department of Neurogenetics, Children's National Medical Center, Washington D.C., USA; Center for Functional and Molecular Imaging, Georgetown University, Washington D.C., USA
| | - Jessica King
- Department of Neurogenetics, Children's National Medical Center, Washington D.C., USA
| | - Guy Helman
- Department of Neurogenetics, Children's National Medical Center, Washington D.C., USA
| | - Ileana Pacheco-Colón
- Center for Functional and Molecular Imaging, Georgetown University, Washington D.C., USA
| | - Kyle Shattuck
- Center for Functional and Molecular Imaging, Georgetown University, Washington D.C., USA
| | - Andrew Breeden
- Center for Functional and Molecular Imaging, Georgetown University, Washington D.C., USA
| | - Rebecca Seltzer
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - John W VanMeter
- Center for Functional and Molecular Imaging, Georgetown University, Washington D.C., USA
| | - Andrea L Gropman
- Department of Neurogenetics, Children's National Medical Center, Washington D.C., USA; Center for Functional and Molecular Imaging, Georgetown University, Washington D.C., USA; George Washington University of Health Sciences, Washington D.C., USA
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33
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Samuel N, Politansky AK, Hoffman R, Itzkovich S, Mandel H. Coagulopathy unmasking hepatic failure in a child with ornithine transcarbamylase deficiency. Isr Med Assoc J 2013; 15:777-779. [PMID: 24449986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Nir Samuel
- Department of Pediatrics B, Meyer Children's Hospital, Rambam Health Care Campus, Haifa, Israel.
| | - Anat K Politansky
- Thrombosis and Hemostasis Unit, Rambam Health Care Campus, Haifa, Israel
| | - Ron Hoffman
- Thrombosis and Hemostasis Unit, Rambam Health Care Campus, Haifa, Israel
| | - Shlomit Itzkovich
- Clinical Nutrition Unit, Meyer Children's Hospital, Rambam Health Care Campus, Haifa, Israel
| | - Hanna Mandel
- Department of Pediatrics B, Meyer Children's Hospital, Rambam Health Care Campus, Haifa, Israel
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Nagasaka H, Yorifuji T, Egawa H, Inui A, Fujisawa T, Komatsu H, Tsukahara H, Uemoto S, Inomata Y. Characteristics of NO cycle coupling with urea cycle in non-hyperammonemic carriers of ornithine transcarbamylase deficiency. Mol Genet Metab 2013; 109:251-4. [PMID: 23669167 DOI: 10.1016/j.ymgme.2013.04.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 04/18/2013] [Indexed: 11/17/2022]
Abstract
Urea cycle deficient patients with prominent hyperammonemic often exhibit abnormal production of nitric oxide (NO), which reduces vascular tone, along with amino acid abnormalities. However, information related to the metabolic changes in heterozygotes of ornithine transcarbamylase deficiency (OTCD) lacking overt hyperammonemia is quite limited. We examined vascular mediators and amino acids in non-hyperammonemic heterozygotes. Twenty-four heterozygous OTCD adult females without hyperammonemic bouts, defined as non-hyperammonemic carriers, were enrolled. We measured blood amino acids constituting urea cycle and nitric oxide (NO) cycle. Blood concentrations of nitrate/nitrite (NOx) as stable NO-metabolites, asymmetric dimethylarginine (ADMA) inhibiting NO synthesis, and endothelin-1 (ET-1) raising vascular tone were also determined. NOx concentrations were significantly lower in non-hyperammonemic carriers (p < 0.01). However, ADMA and ET-1 levels in this group were comparable to those in the age-matched control group. Arginine and citrulline levels were also significantly lower in non-hyperammonemic carriers than in controls (p < 0.01). Of the 24 non-hyperammonemic carriers, 10 often developed headaches. Their daily NOx and arginine levels were significantly lower than those in headache-free carriers (p < 0.05). In three carriers receiving oral l-arginine, blood NOx concentrations were significantly higher. In two of those three, the occurrence of headaches was decreased. These results suggest that NO cycle coupling with the urea cycle is altered substantially even in non-hyperammonemic OTCD carriers, predisposing them to headaches.
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Affiliation(s)
- Hironori Nagasaka
- Department of Pediatrics, Takarazuka City Hospital, 4-5-1 Kohama-cho, Takarazuka 665-0827, Japan.
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Meng LL, Jiang T, Qin L, Ma DY, Chen YL, Han SP, Yu ZB, Guo XR, Hu P, Xu ZF. [Molecular diagnosis of OTC gene mutation in a Chinese family with ornithine transcarbamylase deficiency]. Zhonghua Yi Xue Yi Chuan Xue Za Zhi 2013; 30:195-198. [PMID: 23568734 DOI: 10.3760/cma.j.issn.1003-9406.2013.04.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE To detect potential mutations of OTC gene in a male infant affected with ornithine transcarbamylase deficiency. METHODS Genomic DNA were isolated from peripheral blood samples of family members and 100 healthy individuals. Potential mutations of the 10 exons of OTC gene were screened with PCR and Sanger sequencing. RESULTS A homozygous missense mutation c.917G>C in exon 9, which results in p.R306T, was identified in the infant. Sequencing of the mother and two female members of the family indicated a heterozygous status for the same mutation. The same mutation was not found in other members of the family and 100 healthy controls. CONCLUSION A missense mutation c.917G>C in the OTC gene is responsible for the pathogenesis of the disease. Identification of the mutation can facilitate prenatal diagnosis and genetic counseling for the family.
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Affiliation(s)
- Lu-lu Meng
- The Fourth Clinical Medicine College of Nanjing Medical University, Jiangsu 210029, P.R. China
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Fantur M, Karall D, Scholl-Buergi S, Häberle J, Rauchenzauner M, Fruehwirth M. Recurrent somnolence in a 17-month-old infant: late-onset ornithine transcarbamylase (OTC) deficiency due to the novel hemizygous mutation c.535C > T (p.Leu179Phe). Eur J Paediatr Neurol 2013; 17:112-5. [PMID: 22727265 DOI: 10.1016/j.ejpn.2012.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 05/24/2012] [Accepted: 05/24/2012] [Indexed: 11/18/2022]
Abstract
Herein, we describe a case of a now 28-month-old boy who presented at the age of 17 months with four episodes of recurrent vomiting and somnolence during a period of four months with increasing severity. A comprehensive clinical and metabolic evaluation revealed normal blood pH and blood glucose, normal cerebral computed tomography and electroencephalogram but an elevated plasma ammonia concentration, which raised the suspicion of a urea cycle disorder. The combination of elevated urinary orotic acid and plasma glutamine with normal citrulline suggested the diagnosis of ornithine transcarbamylase (OTC) deficiency, which was confirmed by molecular genetic testing revealing the novel hemizygous mutation c.535C > T (p.Leu179Phe) of the OTC gene. After restitution of anabolism by administration of parenteral glucose, substitution of citrulline and detoxification of ammonia with sodium benzoate, the patient recovered rapidly and is in a stable metabolic and neurological state since then. This case underlines that the diagnosis of a urea cycle defect should be considered in the differential diagnosis of recurrent idiopathic vomiting in combination with unexplained neurological symptoms also beyond the neonatal period due to the possibility of mild or atypical late-onset presentation (e.g. OTC deficiency in hemizygous males).
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Affiliation(s)
- Michaela Fantur
- Dep. of Pediatrics, Hospital St. Vinzenz, Sanatoriumstrasse 43, 6511 Zams, Austria.
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Langendonk JG, Roos JCP, Angus L, Williams M, Karstens FPJ, de Klerk JBC, Maritz C, Ben-Omran T, Williamson C, Lachmann RH, Murphy E. A series of pregnancies in women with inherited metabolic disease. J Inherit Metab Dis 2012; 35:419-24. [PMID: 21918856 DOI: 10.1007/s10545-011-9389-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/07/2011] [Accepted: 08/18/2011] [Indexed: 12/17/2022]
Abstract
In this case series we report 12 pregnancies, in women treated at four centres, illustrating some of the issues that may be encountered during pregnancy by women with inherited metabolic disease. We discuss how specific pregnancy, labour and delivery issues for mothers with methylmalonic acidemia, homocystinuria, propionic acidemia, glutaric acidemia type 1, ornithine transcarbamylase (OTC) deficiency and 3-hydroxy-3-methylglutaric(HMG)-CoA lyase deficiency were managed and the outcome for the mother and child in each case. Eight of the 12 pregnancies resulted in the successful delivery of a liveborn infant. Several women experienced decompensation of their condition during pregnancy or the post-partum period. There was one maternal death in a women with 3-hydroxy-3-methylglutaric(HMG)-CoA lyase deficiency. Pre-pregnancy counselling and co-management of high risk medical patients by obstetricians and specialist physicians with an understanding of the relationship between pregnancy and inherited metabolic disease is essential.
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Affiliation(s)
- Janneke G Langendonk
- Centre for Lysosomal and Metabolic diseases, Departments of Internal Medicine and Pediatrics, Erasmus MC, Rotterdam, The Netherlands
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Wang L, Wang H, Morizono H, Bell P, Jones D, Lin J, McMenamin D, Yu H, Batshaw ML, Wilson JM. Sustained correction of OTC deficiency in spf( ash) mice using optimized self-complementary AAV2/8 vectors. Gene Ther 2012; 19:404-10. [PMID: 21850052 PMCID: PMC3321078 DOI: 10.1038/gt.2011.111] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/18/2011] [Indexed: 12/26/2022]
Abstract
Ornithine transcarbamylase deficiency (OTCD) is the most common inborn error of urea synthesis. Complete OTCD can result in hyperammonemic coma in the neonatal period, which can rapidly become fatal. Current acute therapy involves dialysis; chronic therapy involves the stimulation of alternate nitrogen clearance pathways; and the only curative approach is liver transplantation. Adeno-associated virus (AAV) vector-based gene therapy would add to current treatment options provided the vector delivers high level and stable transgene expression in liver without dose-limiting toxicity. In this study, we employed an AAV2/8-based self-complementary (sc) vector expressing the murine OTC (mOTC) gene under a liver-specific thyroxine-binding globulin promoter and examined the therapeutic effects in a mouse model of OTCD, the spf (ash) mouse. Seven days after a single intravenous injection of vector, treated mice showed complete normalization of urinary orotic acid, a measure of OTC activity. We further improved vector efficacy by incorporating a Kozak or Kozak-like sequence into mOTC complementary DNA, which increased the OTC activity by five or twofold and achieved sustained correction of orotic aciduria for up to 7 months. Our results demonstrate that vector optimizations can significantly improve the efficacy of gene therapy.
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Affiliation(s)
- Lili Wang
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Huan Wang
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Vaccine Research Institute, Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children’s National Medical Center, Children’s Research Institute, Washington, District of Columbia, USA
| | - Peter Bell
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - David Jones
- Center for Genetic Medicine Research, Children’s National Medical Center, Children’s Research Institute, Washington, District of Columbia, USA
| | - Jianping Lin
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Deirdre McMenamin
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Hongwei Yu
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Mark L. Batshaw
- Center for Genetic Medicine Research, Children’s National Medical Center, Children’s Research Institute, Washington, District of Columbia, USA
| | - James M. Wilson
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Division of Transfusion Medicine, University of Pennsylvania, Philadelphia, PA 19104
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Wilson JM, Shchelochkov OA, Gallagher RC, Batshaw ML. Hepatocellular carcinoma in a research subject with ornithine transcarbamylase deficiency. Mol Genet Metab 2012; 105:263-5. [PMID: 22129577 PMCID: PMC3273986 DOI: 10.1016/j.ymgme.2011.10.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 10/25/2011] [Accepted: 10/25/2011] [Indexed: 12/22/2022]
Abstract
A 66 year old woman who is a manifesting heterozygote for ornithine transcarbamylase deficiency (OTCD) presented with hepatocellular carcinoma (HCC). Fourteen years prior to this presentation she participated in a phase I gene therapy study which used an adenoviral vector, thought to be non-oncogenic, to deliver a normal OTC gene to hepatocytes [1]. A recent review of data collected through a national longitudinal study of individuals with urea cycle defects [2,3] suggests that early urea cycle disorders (UCDs) are associated with hepatocellular damage and liver dysfunction in many cases. This may predispose an affected individual to a substantially increased risk of developing HCC, as has been observed in certain other inborn errors of metabolism. We speculate that the underlying urea cycle defect may be the cause of HCC in this individual.
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Affiliation(s)
- James M Wilson
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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41
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Wang L, Morizono H, Lin J, Bell P, Jones D, McMenamin D, Yu H, Batshaw ML, Wilson JM. Preclinical evaluation of a clinical candidate AAV8 vector for ornithine transcarbamylase (OTC) deficiency reveals functional enzyme from each persisting vector genome. Mol Genet Metab 2012; 105:203-11. [PMID: 22133298 PMCID: PMC3270700 DOI: 10.1016/j.ymgme.2011.10.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/31/2011] [Accepted: 10/31/2011] [Indexed: 10/15/2022]
Abstract
Ornithine transcarbamylase deficiency (OTCD), the most common and severe urea cycle disorder, is an excellent model for developing liver-directed gene therapy. No curative therapy exists except for liver transplantation which is limited by available donors and carries significant risk of mortality and morbidity. Adeno-associated virus 8 (AAV8) has been shown to be the most efficient vector for liver-directed gene transfer and is currently being evaluated in a clinical trial for treating hemophilia B. In this study, we generated a clinical candidate vector for a proposed OTC gene therapy trial in humans based on a self-complementary AAV8 vector expressing codon-optimized human OTC (hOTCco) under the control of a liver-specific promoter. Codon-optimization dramatically improved the efficacy of OTC gene therapy. Supraphysiological expression levels and activity of hOTC were achieved in adult spf(ash) mice following a single intravenous injection of hOTCco vector. Vector doses as low as 1×10(10) genome copies (GC) achieved robust and sustained correction of the OTCD biomarker orotic aciduria and clinical protection against an ammonia challenge. Functional expression of hOTC in 40% of liver areas was found in mice treated with a low vector dose of 1×10(9) GC. We suggest that the clinical candidate vector we have developed has the potential to achieve therapeutic effects in OTCD patients.
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Affiliation(s)
- Lili Wang
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hiroki Morizono
- Center for Genetic Medicine Research, Children’s National Medical Center, Children’s Research Institute, Washington, D.C., USA
| | - Jianping Lin
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Peter Bell
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David Jones
- Center for Genetic Medicine Research, Children’s National Medical Center, Children’s Research Institute, Washington, D.C., USA
| | - Deirdre McMenamin
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Hongwei Yu
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Mark L. Batshaw
- Center for Genetic Medicine Research, Children’s National Medical Center, Children’s Research Institute, Washington, D.C., USA
| | - James M. Wilson
- Gene Therapy Program, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Corresponding author: Department of Pathology and Laboratory Medicine University of Pennsylvania, Philadelphia, PA 19104, USA Phone: 215-898-0226; Fax: 215-494-5444
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42
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Sun WH, Yang Y, Zhang YP, Li XT, Zhang M, Cao Y, Wang Y. [Analysis of clinical features, biochemical analysis and gene mutations in one Chinese pedigree with neonatal-onset ornithine transcarbamylase deficiency]. Zhonghua Er Ke Za Zhi 2011; 49:356-360. [PMID: 21624287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
OBJECTIVE This study aimed at understanding clinical features, biochemistry and gene mutation in one Chinese pedigree which had a neonatal-onset ornithine transcarbamylase deficiency (OTCD) boy, and exploring the significance of ornithine transcarbamylase analysis in prenatal diagnosis. METHOD The clinical and biochemical data of one case were analyzed. The amino acids in blood and organic acids in urine were analyzed by mass spectrum technology. The OTC gene mutation was detected using polymerase chain reaction (PCR) and DNA direct sequencing for the case, his parents and the fetus amniocyte and her blood after birth. RESULT The age of onset was 3 days after birth, he began to have poor reaction, difficulty to feed, high blood ammonia, infection, slight metabolic acidosis, which were consistent with the clinical diagnosis of urea cycle disorders. The boy died at the age of 9 days. Citrulline of blood was detected twice, and were 0.86 µm and 1.06 µm, respectively. The orotic acid was elevated (124 µm/M Creatinine), and urine lactic acid was significantly elevated. The citrulline and orotic acid in his parents and their second baby were normal in DBS and urine. One nonsense mutation in the OTC gene was found at the exon 9 (C. 958 C > T) and his mother was the heterozygote, which caused an arginine to terminate the code at position 320 of the protein (R320X). Two other mutations were also detected at intron 9 (C.1005 + 132 InsT) and intron 5 (C.542 + 134 G > G/A). But the analysis of his father's DNA, the fetus amniocyte and her blood was normal. CONCLUSION The mutation of C. 958 C > T in OTC gene may occur during neonatal period. This mutation would result in a very severe symptom, even die suddenly several days after birth, if it was a boy. It needs more researches to discuss whether the C.1005 + 132 InsT in intron 9 and C.542 + 134 G > G/A in intron 5 were associated with the neonatal-onset OTCD. The DNA analysis of OTC gene could be utilized for the prenatal diagnosis.
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Affiliation(s)
- Wei-hua Sun
- Pediatrics Institute, Children's Hospital of Fudan University, Shanghai 201102, China
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Quintero-Rivera F, Deignan JL, Peredo J, Grody WW, Crandall B, Sims M, Cederbaum SD. An exon 1 deletion in OTC identified using chromosomal microarray analysis in a mother and her two affected deceased newborns: implications for the prenatal diagnosis of ornithine transcarbamylase deficiency. Mol Genet Metab 2010; 101:413-6. [PMID: 20817516 DOI: 10.1016/j.ymgme.2010.08.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 08/06/2010] [Accepted: 08/07/2010] [Indexed: 11/24/2022]
Abstract
We describe the outcome of two consecutive pregnancies with a clinical presentation of ornithine transcarbamylase (OTC) deficiency (OTCD) without a molecular diagnosis. A 119kb deletion on Xp11.4 including the OTC gene was detected in the mother. The same deletion was identified in the blood spots from deceased male newborns. In patients with a clinical and biochemical presentation of OTCD and negative OTC sequencing, whole genome or targeted chromosomal microarray analysis (CMA) with coverage of the OTC and neighboring genes should be performed as a reflex test.
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Affiliation(s)
- Fabiola Quintero-Rivera
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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Lin HY, Lin HY, Lin SP. Novel human pathological mutations. Gene symbol: OTC. Disease: ornithine transcarbamylase deficiency. Hum Genet 2010; 127:475. [PMID: 21488237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Hsiang-Yu Lin
- Department of Pediatrics, Mackay Memorial Hospital and Mackay Medicine, Nursing and Management College, Taipei, Taiwan, ROC.
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Coman D, Yaplito-Lee J, La P, Nasioulas S, Bruno D, Slater HR, Stock-Myer SE, Lynch EL, Gardner RJM. Three Mendelian disorders (chronic granulomatous disease, retinitis pigmentosa, ornithine transcarbamylase deficiency) in a young woman with an X chromosome deletion, del(X)(p11.4p21.1). Mol Genet Metab 2010; 99:329. [PMID: 20036594 DOI: 10.1016/j.ymgme.2009.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 11/20/2009] [Indexed: 11/20/2022]
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Balasubramaniam S, Rudduck C, Bennetts B, Peters G, Wilcken B, Ellaway C. Contiguous gene deletion syndrome in a female with ornithine transcarbamylase deficiency. Mol Genet Metab 2010; 99:34-41. [PMID: 19783189 DOI: 10.1016/j.ymgme.2009.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 08/21/2009] [Accepted: 08/21/2009] [Indexed: 10/20/2022]
Abstract
OTC deficiency, a partially dominant X-linked trait, is the most frequent inborn error of the urea cycle. We describe a female patient with a contiguous gene deletion syndrome encompassing the OTC, DMD, RPGR, CYBB and XK genes, amongst others, only manifesting features of OTC deficiency. Molecular characterization was ascertained by MLPA and confirmed by CGH microarray, which revealed an 8.7 Mb deletion of the X-chromosome. Complete de novo deletion of the OTC gene led to a severe clinical phenotype in the proband. The application of high resolution molecular genetic techniques such as MLPA and array CGH, in mutation negative OTC cases allows the identification of chromosomal rearrangements, such as large deletions and provides information for accurate genetic counseling and prenatal diagnosis.
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Affiliation(s)
- S Balasubramaniam
- Genetic Metabolic Disorders Service, The Children's Hospital at Westmead, Sydney, NSW 2145, Australia
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47
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Gene therapy: concepts and methods. Few applications so far. Prescrire Int 2009; 18:276-9. [PMID: 20027718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
(1) Gene therapy consists of inserting foreign genetic material into a patient's cells to correct a health disorder; (2) Only a fraction of gene therapy trials involve hereditary single-gene disorders. Most trials focus on acquired disorders such as cancer and cardiovascular disease; (3) The therapeutic gene can be delivered directly into the target organ or the general circulation, or alternatively into cells that are first isolated from the patient and then reinjected; (4) One of the main problems with gene therapy is finding an appropriate vector (viral or non-viral) that is both effective and safe. Most currently available vectors confer only weak and transient therapeutic gene expression. In addition, many carry major risks such as immunological disorders and oncogenicity; (5) In early 2009, only one therapeutic gene product is commercially available, in China.
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Cunningham SC, Spinoulas A, Carpenter KH, Wilcken B, Kuchel PW, Alexander IE. AAV2/8-mediated correction of OTC deficiency is robust in adult but not neonatal Spf(ash) mice. Mol Ther 2009; 17:1340-6. [PMID: 19384294 PMCID: PMC2835243 DOI: 10.1038/mt.2009.88] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 03/30/2009] [Indexed: 11/08/2022] Open
Abstract
Ornithine transcarbamylase (OTC) deficiency, the most common urea cycle disorder, is associated with severe hyperammonemia accompanied by a high risk of neurological damage and death in patients presenting with the neonatal-onset form. Contemporary therapies, including liver transplantation, remain inadequate with considerable morbidity, justifying vigorous investigation of alternate therapies. Clinical evidence suggests that as little as 3% normal enzyme activity is sufficient to ameliorate the severe neonatal phenotype, making OTC deficiency an ideal model for the development of liver-targeted gene therapy. In this study, we investigated metabolic correction in neonatal and adult male OTC-deficient Spf(ash) mice following adeno-associated virus (AAV)2/8-mediated delivery of the murine OTC complementary DNA under the transcriptional control of a liver-specific promoter. Substantially supraphysiological levels of OTC enzymatic activity were readily achieved in both adult and neonatal mice following a single intraperitoneal (i.p.) injection, with metabolic correction in adults being robust and life-long. In the neonates, however, full metabolic correction was transient, although modest levels of OTC expression persisted into adulthood. Although not directly testable in Spf(ash) mice, these levels were theoretically sufficient to prevent hyperammonemia in a null phenotype. This loss of expression in the neonatal liver is the consequence of hepatocellular proliferation and presents an added challenge to human therapy.
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Affiliation(s)
- Sharon C Cunningham
- Gene Therapy Research Unit, Children's Medical Research Institute and The Children's Hospital at Westmead, Wentworthville, New South Wales, Australia
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Bürle M, Mende H, Plum U, Bluthardt M, Walka M, Geldner G. [Ornithine transcarbamylase deficiency in adolescence and adulthood: first manifestation with life-threatening decompensation]. Anaesthesist 2009; 58:594-601. [PMID: 19468698 DOI: 10.1007/s00101-009-1540-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Ornithine transcarbamylase (OTC) deficiency is the most frequent innate disorder of the urea cycle and is X-chromosome linked. The disease normally manifests itself shortly after birth and is fatal when untreated. Due to the different expression and X-chromosomal inheritance the manifestation of symptoms can appear later particularly in girls and young women. The first symptoms are non-specific signs of elevated cerebral pressure as a result of a hyperammonemia, which range from nausea and headache up to cerebral herniation with fatal outcome. Measurement of plasma ammonia levels is a simple yet important screening test for patients with unexpected stupor or delirium. CASE REPORTS The two case reports show the clinical range from acute decompensation with acute cerebral herniation followed by fatal outcome to recovery under emergency therapy without substantial neurological deficits. THERAPY Emergency treatment consists of symptomatic securing of vital parameters and an immediate reduction in the ammonia level using high calorie, protein-free nutrition to avoid catabolism together with administration of arginine, benzoate or phenyl butyrate. In cases of coma with severe cerebral edema and the threat of a herniation reaction or excessive ammonia levels, emergency hemodialysis must be immediately carried out. CONCLUSIONS In the clinical routine it is extremely important to consider a metabolic defect at an early phase and among others to determine the ammonia level so that the appropriate treatment can be instigated in time.
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Affiliation(s)
- M Bürle
- Klinik für Anästhesiologie, Intensivmedizin, Schmerztherapie und Notfallmedizin, Klinikum Ludwigsburg, Posilipostr. 4, 71640, Ludwigsburg, Deutschland.
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Abstract
Almost a decade has passed since the untimely death of Jesse Gelsinger. The reflections of Dr. Wilson and efforts made on a national scale to address various ethical issues in biomedical research provide an opportunity to consider what progress has been made in efforts to build and restore the public's trust in biomedical research. The restoration of public trust is especially critical in the aftermath of tragic events like Mr. Gelsinger's death and the authors note the need for greater emphasis on building public trust than has occurred to date in the broader biomedical research community.
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Affiliation(s)
- Mark Yarborough
- Center for Bioethics and Humanities, University of Colorado Denver, Mail Stop B 137, 13120 E. 19th Avenue, Aurora, CO 80045, USA.
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