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Benefits of tailored disease management in improving tremor, white matter hyperintensities, and liver enzymes in a child with heterozygous X-linked ornithine transcarbamylase deficiency. Mol Genet Metab Rep 2022; 33:100891. [PMID: 36620387 PMCID: PMC9817482 DOI: 10.1016/j.ymgmr.2022.100891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 01/11/2023] Open
Abstract
We report the case of a 19-month-old girl with late-onset ornithine transcarbamylase (OTC) deficiency initially referred to gastroenterology for intermittent vomiting lasting a year and abnormal liver enzymes (AST 730 U/L [reference range 26-55 U/L]; ALT 1213 U/L [reference range 11-30 U/L]) without hepatomegaly. While the patient was hospitalized for liver biopsy, intermittent tremors of the upper extremities with varying severity were noted. The patient was presumed to have hyperammonemia secondary to acute liver failure and was discharged after 5 days; follow-up monitoring led to readmission 7 days later. A brain MRI showed nonspecific bilateral pericallosal and bifrontal white matter FLAIR hyperintensities. These findings raised suspicion for a metabolic disease and prompted a genetics consultation. After inconclusive biochemical testing and worsening clinical status, rapid whole genome sequencing results were obtained identifying a novel, de novo, likely pathogenic, variant c.608C > T (p.Ser203Phe) in the OTC gene. The patient was promptly started on an oral nitrogen scavenger, citrulline supplementation, and protein restriction. Ammonia and glutamine levels normalized within 1 month of treatment and have stayed within the goal ranges with continued tailoring of treatment. Her parents noted resolution of vomiting and improved mood stability. Liver enzymes normalized after 2 months of treatment. The tremor, identified as asterixis, improved and a repeat brain MRI 3 months after the initial imaging showed near-complete resolution of previous white matter hyperintensities.
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Key Words
- ALT, alanine transaminase
- AST, aspartate aminotransferase
- Asterixis
- BASC-3, Behavior Assessment System for Children
- BCAA, branched-chain amino acid
- FLAIR, fluid-attenuated inversion recovery
- GGT, gamma-glutamyl transferase
- Late onset
- MRI, magnetic resonance imaging
- MRS, magnetic resonance spectroscopy
- Manifesting heterozygote
- OTC, ornithine transcarbamylase
- Ornithine transcarbamylase deficiency
- PT, prothrombin time
- Partial onset
- TID, 3 times a day
- UCD, urea cycle disorder
- Urea cycle disorder
- WPPSI-IV, Wechsler Preschool and Primary Scale of Intelligence
- X linked
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Sen K, Whitehead M, Castillo Pinto C, Caldovic L, Gropman A. Fifteen years of urea cycle disorders brain research: Looking back, looking forward. Anal Biochem 2022; 636:114343. [PMID: 34637785 PMCID: PMC8671367 DOI: 10.1016/j.ab.2021.114343] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/13/2021] [Accepted: 08/17/2021] [Indexed: 01/03/2023]
Abstract
Urea cycle disorders (UCD) are inherited diseases resulting from deficiency in one of six enzymes or two carriers that are required to remove ammonia from the body. UCD may be associated with neurological damage encompassing a spectrum from asymptomatic/mild to severe encephalopathy, which results in most cases from Hyperammonemia (HA) and elevation of other neurotoxic intermediates of metabolism. Electroencephalography (EEG), Magnetic resonance imaging (MRI) and Proton Magnetic resonance spectroscopy (MRS) are noninvasive measures of brain function and structure that can be used during HA to guide management and provide prognostic information, in addition to being research tools to understand the pathophysiology of UCD associated brain injury. The Urea Cycle Rare disorders Consortium (UCDC) has been invested in research to understand the immediate and downstream effects of hyperammonemia (HA) on brain using electroencephalogram (EEG) and multimodal brain MRI to establish early patterns of brain injury and to track recovery and prognosis. This review highlights the evolving knowledge about the impact of UCD and HA in particular on neurological injury and recovery and use of EEG and MRI to study and evaluate prognostic factors for risk and recovery. It recognizes the work of others and discusses the UCDC's prior work and future research priorities.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Children's National Hospital, Washington D.C., United States
| | - Matthew Whitehead
- Division of Radiology, Children's National Hospital, Washington D.C., United States
| | | | - Ljubica Caldovic
- Childrens' Research Institute, Children's National Hospital, Washington D.C., United States
| | - Andrea Gropman
- Division of Neurogenetics and Neurodevelopmental Pediatrics, Children's National Hospital, Washington D.C., United States.
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3
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Castillo-Pinto C, Sen K, Gropman A. Neuromonitoring in Rare Disorders of Metabolism. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2021; 94:645-655. [PMID: 34970103 PMCID: PMC8686771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Inborn errors of metabolism (IEM) are a unique class of genetic diseases due to mutations in genes involved in key metabolic pathways. The combined incidence of IEM has been estimated to be as high as 1:1000. Urea Cycle disorders (UCD), one class of IEM, can present with cerebral edema and represent a possible target to explore the utility of different neuromonitoring techniques during an hyperammonemic crisis. The last two decades have brought advances in the early identification and comprehensive management of UCD, including further understanding of neuroimaging patterns associated with neurocognitive function. Nonetheless, very important questions remain about the potential acute neurotoxic effects of hyperammonemia to better understand how to treat and prevent secondary brain injury. In this review, we describe existing neuromonitoring techniques that have been used in rare metabolic disorders to assess and allow amelioration of ongoing brain injury. Directions of future research should be focused on identifying new diagnostic approaches in the management of metabolic crises to optimize care and reduce long term morbidity and mortality in patients with IEM.
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Affiliation(s)
| | - Kuntal Sen
- Neurogenetics and Neurodevelopmental Pediatrics, Children's National, Washington DC, USA
| | - Andrea Gropman
- Neurogenetics and Neurodevelopmental Pediatrics, Children's National, Washington DC, USA
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4
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Stergachis AB, Krier JB, Merugumala SK, Berry GT, Lin AP. Clinical utility of brain MRS imaging of patients with adult-onset non-cirrhotic hyperammonemia. Mol Genet Metab Rep 2021; 27:100742. [PMID: 33763331 PMCID: PMC7973242 DOI: 10.1016/j.ymgmr.2021.100742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 11/15/2022] Open
Abstract
Adult-onset non-cirrhotic hyperammonemia (NCH) is a rare, but often fatal condition that can result in both reversible and irreversible neurological defects. Here we present five cases of adult-onset non-cirrhotic hyperammonemia wherein brain magnetic resonance spectroscopy (MRS) scans for cerebral glutamine (Gln) and myo-inositol (mI) levels helped guide clinical management. Specifically, we demonstrate that when combined with traditional brain magnetic resonance imaging (MRI) scans, cerebral Gln and mI MRS can help disentangle the reversible from irreversible neurological defects associated with hyperammonemic crisis. Specifically, we demonstrate that whereas an elevated brain MRS Gln level is associated with reversible neurological defects, markedly low mI levels are associated with a risk for irreversible neurological defects such as central pontine myelinolysis. Overall, our findings indicate the utility of brain MRS in guiding clinical care and prognosis in patients with adult-onset non-cirrhotic hyperammonemia.
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Affiliation(s)
- Andrew B Stergachis
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA, USA.,Brotman Baty Institute for Precision Medicine, Seattle, WA, USA
| | - Joel B Krier
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Sai K Merugumala
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Gerard T Berry
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexander P Lin
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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5
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Sen K, Whitehead MT, Gropman AL. Multimodal imaging in urea cycle-related neurological disease - What can imaging after hyperammonemia teach us? ACTA ACUST UNITED AC 2020; 5:87-95. [PMID: 33344172 PMCID: PMC7739971 DOI: 10.3233/trd-200048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Urea cycle-related brain disease may take on variable neuroimaging manifestations, ranging from normal to abnormal with or without a signature appearance. In the past, we have described the usefulness of multimodal imaging in identifying biomarkers of neuronal injury in UCD patients. In this study, we report unique findings in an adolescent male with neonatal-onset OTC deficiency after an episode of hyperammonemia. MATERIALS AND METHODS Multiplanar, multisequence MR imaging (T1WI, T2WI, T2 FLAIR, diffusion weighted images and gradient echo) of the brain was performed on seven separate occasions over the course following the acute illness; first five exams were performed within 28 days of admission and the final two exams were performed approximately 3 and 5 months later. RESULTS 1.The initial MR revealed increased signal on T2WI in the basal ganglia, claustrum and frontoparietal white matter; which remained stable over time. By the 5th exam, signal changes had developed in frontal cortex; reflecting permanent injury. 2. DTI tractography of the corticospinal tracts displayed revealed diminution of the number of projectional and commissural fibers over time. 3. Blood flow measurements demonstrated hypoperfusion on the fifth exams followed by hyperperfusion on the final two studies. 4. MR spectroscopy demonstrated that glutamine was elevated during hyperammonemia with myoinositol reduction, reflecting osmotic buffering. CONCLUSION This particular multimodal magnetic resonance neuroimaging showed novel, temporally specific manifestations over the disease course in OTC deficiency. This prospective imaging study expands our understanding of the effect of hyperammonemia on the structure and biochemistry of the nervous system.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, DC, USA
| | - Matthew T Whitehead
- Department of Radiology, Children's National Hospital, Washington, DC, USA.,George Washington University of Medicine and Health Sciences, Washington, DC, USA
| | - Andrea L Gropman
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, DC, USA.,George Washington University of Medicine and Health Sciences, Washington, DC, USA
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Sen K, Castillo Pinto C, Gropman AL. Expanding Role of Proton Magnetic Resonance Spectroscopy: Timely Diagnosis and Treatment Initiation in Partial Ornithine Transcarbamylase Deficiency. J Pediatr Genet 2020; 10:77-80. [PMID: 33552645 DOI: 10.1055/s-0040-1709670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/11/2020] [Indexed: 12/21/2022]
Abstract
We report the case of a 3-year-old male patient who presented with a 3-day history of altered mental status, emesis, and abdominal pain in the setting of a viral illness. A rapid screening revealed a high ammonia level and after reviewing his proton magnetic resonance spectroscopy (1H MRS) which showed the classic triad of high glutamate, low choline, and myoinositol, a diagnosis of ornithine transcarbamylase deficiency (OTCD) was made within 6 hours of presentation. Therapy with sodium phenylbutyrate and sodium benzoate was initiated and patient was discharged after 3 days with no neurologic disability. Biochemical and molecular testing eventually confirmed the diagnosis. 1H MRS is a practical and fast neuroimaging modality that can aid in diagnosis of OTCD and enables faster initiation of treatment in acute settings.
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Affiliation(s)
- Kuntal Sen
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, District of Columbia, United States
| | - Carlos Castillo Pinto
- Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, District of Columbia, United States
| | - Andrea L Gropman
- Division of Neurogenetics and Developmental Pediatrics, Center for Neuroscience and Behavioral Medicine, Children's National Hospital, Washington, District of Columbia, United States
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7
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Anderson A, Gropman A, Le Mons C, Stratakis C, Gandjbakhche A. Evaluation of neurocognitive function of prefrontal cortex in ornithine transcarbamylase deficiency. Mol Genet Metab 2020; 129:207-212. [PMID: 31952925 PMCID: PMC7416502 DOI: 10.1016/j.ymgme.2019.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/30/2019] [Accepted: 12/30/2019] [Indexed: 02/02/2023]
Abstract
Hyperammonia due to ornithine transcarbamylase deficiency (OTCD) can cause a range of deficiencies in domains of executive function and working memory. Only a few fMRI studies have focused on neuroimaging data in a population with OTCD. Yet, there is a need for monitoring the disease progression and neurocognitive function in this population. In this study, we used a non-invasive neuroimaging technique, functional Near Infrared Spectroscopy (fNIRS), to examine the hemodynamics of prefrontal cortex (PFC) based on neural activation in an OTCD population. Using fNIRS, we measured the activation in PFC of the participants while performing the Stroop task. Behavioral assessment such as reaction time and correct response were recorded. We investigated the difference in behavioral measures as well as brain activation in left and right PFC in patients with OTCD and controls. Results revealed a distinction in left PFC activation between controls and patients with OTCD, where control subjects showed higher task related activation increase. Subjects with OTCD also exhibited bilateral increase in PFC activation. There was no significant difference in response time or correct response between the two groups. Our findings suggest the alterations in neurocognitive function of PFC in OTCD compared to the controls despite the behavioral profiles exhibiting no such differences. This is a first study using fNIRS to examine a neurocognitive function in OTCD population and can provide a novel insight into the screening of OTCD progression and examining neurocognitive changes.
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Affiliation(s)
- Afrouz Anderson
- NIH, National Institute of Child Health and Human Development, Bethesda, MD 20892, United States of America
| | - Andrea Gropman
- Children's National Medical Center, Division of Neurogenetics and Neurodevelopmental Pediatrics, Washington, DC 20010, United States of America
| | - Cynthia Le Mons
- National Urea Cycle Disorders Foundation, Pasadena, California 91105
| | - Constantine Stratakis
- NIH, National Institute of Child Health and Human Development, Bethesda, MD 20892, United States of America
| | - Amir Gandjbakhche
- NIH, National Institute of Child Health and Human Development, Bethesda, MD 20892, United States of America.
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8
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Gropman AL, Anderson A. Novel imaging technologies for genetic diagnoses in the inborn errors of metabolism. JOURNAL OF TRANSLATIONAL GENETICS AND GENOMICS 2020; 4:429-445. [PMID: 35529470 PMCID: PMC9075742 DOI: 10.20517/jtgg.2020.09] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Many inborn errors of metabolism and genetic disorders affect the brain. The brain biochemistry may differ from that in the periphery and is not accessible by simple blood and urine sampling. Therefore, neuroimaging has proven to be a valuable tool to not only evaluate the brain structure, but also biochemistry, blood flow and function. Neuroimaging in patients with inborn errors of metabolism can include additional sequences in addition to T1 and T2-weighted imaging because in early stages, there may be no significant findings on the routine sequnces due to the lack of sensitivity or the evolution of abnormalities lags behind the ability of the imaging to detect it. In addition, findings on T1 and T2-weighted imaging of several inborn errors of metabolism may be non-specific and be seen in other non-genetic conditions. Therefore, additional neuroimaging modalities that have been employed including diffusion tensor imaging (DTI), magnetic resonance spectroscopy, functional MRI (fMRI), functional near infrared spectroscopy (fNIRS), or positron emission tomography (PET) imaging may further inform underlying changes in myelination, biochemistry, and functional connectivity. The use of Magnetic Resonance Spectroscopy in certain disorders may add a level of specificity depending upon the metabolite levels that are abnormal, as well as provide information about the process of brain injury (i.e., white matter, gray matter, energy deficiency, toxic buildup or depletion of key metabolites). It is even more challenging to understand how genetic or metabolic disorders contribute to short and/or long term changes in cognition which represent the downstream effects of IEMs. In order to image “cognition” or the downstream effects of a metabolic disorder on domains of brain function, more advanced techniques are required to analyze underlying fiber tracts or alternatively, methods such as fMRI enable generation of brain activation maps after both task based and resting state conditions. DTI can be used to look at changes in white matter tracks. Each imaging modality can explore an important aspect of the anatomy, physiology or biochemisty of the central nervous system. Their properties, pros and cons are discussed in this article. These imaging modalities will be discussed in the context of several inborn errors of metabolism including Galactosemia, Phenylketonruia, Maple syrup urine disease, Methylmalonic acidemia, Niemann-Pick Disease, type C1, Krabbe Disease, Ornithine transcarbamylase deficiency, Sjogren Larsson syndrome, Pelizeaus-Merzbacher disease, Pyruvate dehydrogenase deficiency, Nonketotic Hyperglycinemia and Fabry disease. Space constraints do not allow mention of all the disorders in which one of these modalities has been investigated, or where it would add value to diagnosis or disease progression.
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Affiliation(s)
- Andrea L Gropman
- Department of Neurology, Children's National Medical Center, Washington, DC 20010, USA
| | - Afrouz Anderson
- Department of Research, Focus Foundation, Crofton, MD 21035, USA
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Häberle J, Burlina A, Chakrapani A, Dixon M, Karall D, Lindner M, Mandel H, Martinelli D, Pintos-Morell G, Santer R, Skouma A, Servais A, Tal G, Rubio V, Huemer M, Dionisi-Vici C. Suggested guidelines for the diagnosis and management of urea cycle disorders: First revision. J Inherit Metab Dis 2019; 42:1192-1230. [PMID: 30982989 DOI: 10.1002/jimd.12100] [Citation(s) in RCA: 241] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 04/04/2019] [Accepted: 04/08/2019] [Indexed: 02/06/2023]
Abstract
In 2012, we published guidelines summarizing and evaluating late 2011 evidence for diagnosis and therapy of urea cycle disorders (UCDs). With 1:35 000 estimated incidence, UCDs cause hyperammonemia of neonatal (~50%) or late onset that can lead to intellectual disability or death, even while effective therapies do exist. In the 7 years that have elapsed since the first guideline was published, abundant novel information has accumulated, experience on newborn screening for some UCDs has widened, a novel hyperammonemia-causing genetic disorder has been reported, glycerol phenylbutyrate has been introduced as a treatment, and novel promising therapeutic avenues (including gene therapy) have been opened. Several factors including the impact of the first edition of these guidelines (frequently read and quoted) may have increased awareness among health professionals and patient families. However, under-recognition and delayed diagnosis of UCDs still appear widespread. It was therefore necessary to revise the original guidelines to ensure an up-to-date frame of reference for professionals and patients as well as for awareness campaigns. This was accomplished by keeping the original spirit of providing a trans-European consensus based on robust evidence (scored with GRADE methodology), involving professionals on UCDs from nine countries in preparing this consensus. We believe this revised guideline, which has been reviewed by several societies that are involved in the management of UCDs, will have a positive impact on the outcomes of patients by establishing common standards, and spreading and harmonizing good practices. It may also promote the identification of knowledge voids to be filled by future research.
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Affiliation(s)
- Johannes Häberle
- University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
| | - Alberto Burlina
- Division of Inborn Metabolic Disease, Department of Pediatrics, University Hospital Padua, Padova, Italy
| | - Anupam Chakrapani
- Department of Metabolic Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Marjorie Dixon
- Dietetics, Great Ormond Street Hospital for Children, NHS Trust, London, UK
| | - Daniela Karall
- Clinic for Pediatrics, Division of Inherited Metabolic Disorders, Medical University of Innsbruck, Innsbruck, Austria
| | - Martin Lindner
- University Children's Hospital, Frankfurt am Main, Germany
| | - Hanna Mandel
- Institute of Human Genetics and metabolic disorders, Western Galilee Medical Center, Nahariya, Israel
| | - Diego Martinelli
- Division of Metabolism, Bambino Gesù Children's Hospital, Rome, Italy
| | - Guillem Pintos-Morell
- Centre for Rare Diseases, University Hospital Vall d'Hebron, Barcelona, Spain
- CIBERER_GCV08, Research Institute IGTP, Barcelona, Spain
- Universitat Autònoma de Barcelona, Barcelona, Spain
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anastasia Skouma
- Institute of Child Health, Agia Sofia Children's Hospital, Athens, Greece
| | - Aude Servais
- Service de Néphrologie et maladies métaboliques adulte Hôpital Necker 149, Paris, France
| | - Galit Tal
- The Ruth Rappaport Children's Hospital, Rambam Medical Center, Haifa, Israel
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia (IBV-CSIC), Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER), Valencia, Spain
| | - Martina Huemer
- University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland
- Department of Paediatrics, Landeskrankenhaus Bregenz, Bregenz, Austria
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10
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Buerger C, Garbade SF, Alber FD, Waisbren SE, McCarter R, Kölker S, Burgard P. Impairment of cognitive function in ornithine transcarbamylase deficiency is global rather than domain-specific and is associated with disease onset, sex, maximum ammonium, and number of hyperammonemic events. J Inherit Metab Dis 2019; 42:243-253. [PMID: 30671983 PMCID: PMC7439789 DOI: 10.1002/jimd.12013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/18/2018] [Accepted: 11/12/2018] [Indexed: 12/15/2022]
Abstract
Beginning in 2006, the Urea Cycle Disorders Consortium (UCDC) has conducted a longitudinal study of eight inherited deficiencies of enzymes and transporters of the urea cycle, including 444 individuals with ornithine transcarbamylase deficiency (OTCD), of whom 300 (67 males, 233 females) received psychological evaluation. In a cross-sectional study (age range, 3-71 years), analysis of covariance (ANCOVA) determined the association between outcomes in five cognitive domains (global intelligence, executive functions, memory, visuomotor integration, visual perception) and sex, age at testing and timing of disease onset defined as early onset (≤28 days; EO), late onset (LO), or asymptomatic (AS). The dataset of 183 subjects with complete datasets (31 males, 152 females) revealed underrepresentation of EO subjects (2 males, 4 females), who were excluded from the ANCOVA. Although mean scores of LO and AS individuals were within 1 SD of the population norm, AS subjects attained significantly higher scores than LO subjects and males higher scores than females. Correlations between cognitive domains were high, particularly intelligence proved to be a distinguished indicator for cognitive functioning. Maximum plasma ammonium concentration and intelligence correlated significantly higher in EO (r = -0.47) than in LO subjects (r = 0.04). Correlation between the number of hyperammonemic events and intelligence scores were similar for EO (r = -0.30) and LO (r = -0.26) individuals. The number of clinical symptoms was significantly associated with intelligence (r = -0.28) but not with scores in other domains. Results suggest that OTCD has a global impact on cognitive functioning rather than a specific effect on distinct cognitive domains.
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Affiliation(s)
- Corinna Buerger
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Sven F. Garbade
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Fabienne Dietrich Alber
- Division of Metabolism and Children’s Research Centre, University Children’s Hospital Zurich, Zurich, Switzerland
| | - Susan E. Waisbren
- Division of Genetics and Genomics, Children’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Robert McCarter
- Center for Translational Sciences, Children’s National Health System, The George Washington University, Washington, District of Columbia
| | - Stefan Kölker
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Peter Burgard
- Division of Neuropaediatrics and Inherited Metabolic Diseases, Centre for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
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11
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O'Donnell-Luria AH, Lin AP, Merugumala SK, Rohr F, Waisbren SE, Lynch R, Tchekmedyian V, Goldberg AD, Bellinger A, McFaline-Figueroa JR, Simon T, Gershanik EF, Levy BD, Cohen DE, Samuels MA, Berry GT, Frank NY. Brain MRS glutamine as a biomarker to guide therapy of hyperammonemic coma. Mol Genet Metab 2017; 121:9-15. [PMID: 28408159 DOI: 10.1016/j.ymgme.2017.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 11/28/2022]
Abstract
Acute idiopathic hyperammonemia in an adult patient is a life-threatening condition often resulting in a rapid progression to irreversible cerebral edema and death. While ammonia-scavenging therapies lower blood ammonia levels, in comparison, clearance of waste nitrogen from the brain may be delayed. Therefore, we used magnetic resonance spectroscopy (MRS) to monitor cerebral glutamine levels, the major reservoir of ammonia, in a gastric bypass patient with hyperammonemic coma undergoing therapy with N-carbamoyl glutamate and the ammonia-scavenging agents, sodium phenylacetate and sodium benzoate. Improvement in mental status mirrored brain glutamine levels, as coma persisted for 48h after plasma ammonia normalized. We hypothesize that the slower clearance for brain glutamine levels accounts for the delay in improvement following initiation of treatment in cases of chronic hyperammonemia. We propose MRS to monitor brain glutamine as a noninvasive approach to be utilized for diagnostic and therapeutic monitoring purposes in adult patients presenting with idiopathic hyperammonemia.
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Affiliation(s)
- Anne H O'Donnell-Luria
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alexander P Lin
- Department of Radiology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Sai K Merugumala
- Department of Radiology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Frances Rohr
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Susan E Waisbren
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Rebecca Lynch
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | | | - Aaron D Goldberg
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Andrew Bellinger
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | | | - Tracey Simon
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | | | - Bruce D Levy
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - David E Cohen
- Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Martin A Samuels
- Department of Neurology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Gerard T Berry
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Natasha Y Frank
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, VA Boston Healthcare System, Boston, MA 02115, USA.
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Barkovich E, Robinson C, Gropman A. Brain biomarkers and neuroimaging to diagnose urea cycle disorders and assess prognosis. Expert Opin Orphan Drugs 2016. [DOI: 10.1080/21678707.2016.1242407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Waisbren SE, Gropman AL, Batshaw ML. Improving long term outcomes in urea cycle disorders-report from the Urea Cycle Disorders Consortium. J Inherit Metab Dis 2016; 39:573-84. [PMID: 27215558 PMCID: PMC4921309 DOI: 10.1007/s10545-016-9942-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 12/31/2022]
Abstract
The Urea Cycle Disorders Consortium (UCDC) has conducted, beginning in 2006, a longitudinal study (LS) of eight enzyme deficiencies/transporter defects associated with the urea cycle. These include N-acetylglutamate synthase deficiency (NAGSD); Carbamyl phosphate synthetase 1 deficiency (CPS1D); Ornithine transcarbamylase deficiency (OTCD); Argininosuccinate synthetase deficiency (ASSD) (Citrullinemia); Argininosuccinate lyase deficiency (ASLD) (Argininosuccinic aciduria); Arginase deficiency (ARGD, Argininemia); Hyperornithinemia, hyperammonemia, homocitrullinuria (HHH) syndrome (or mitochondrial ornithine transporter 1 deficiency [ORNT1D]); and Citrullinemia type II (mitochondrial aspartate/glutamate carrier deficiency [CITRIN]). There were 678 UCD patients enrolled in 14 sites in the U.S., Canada, and Europe at the writing of this paper. This review summarizes findings of the consortium related to outcome, focusing primarily on neuroimaging findings and neurocognitive function. Neuroimaging studies in late onset OTCD offered evidence that brain injury caused by biochemical dysregulation may impact functional neuroanatomy serving working memory processes, an important component of executive function and regulation. Additionally, there were alteration in white mater microstructure and functional connectivity at rest. Intellectual deficits in OTCD and other urea cycle disorders (UCD) vary. However, when neuropsychological deficits occur, they tend to be more prominent in motor/performance areas on both intelligence tests and other measures. In some disorders, adults performed significantly less well than younger patients. Further longitudinal follow-up will reveal whether this is due to declines throughout life or to improvements in diagnostics (especially newborn screening) and treatments in the younger generation of patients.
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Affiliation(s)
- Susan E Waisbren
- Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Andrea L Gropman
- Children's Research Institute, Children's National Health System, Washington, DC, USA
| | - Mark L Batshaw
- Departments of Pediatrics and Neurology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
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Switch from Sodium Phenylbutyrate to Glycerol Phenylbutyrate Improved Metabolic Stability in an Adolescent with Ornithine Transcarbamylase Deficiency. JIMD Rep 2016; 31:11-14. [PMID: 27000017 DOI: 10.1007/8904_2016_551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/25/2016] [Accepted: 02/29/2016] [Indexed: 12/30/2022] Open
Abstract
A male patient, born in 1999, was diagnosed with ornithine transcarbamylase deficiency as neonate and was managed with a strict low-protein diet supplemented with essential amino acids, L-citrulline, and L-arginine as well as sodium benzoate. He had an extensive history of hospitalizations for hyperammonemic crises throughout childhood and early adolescence, which continued after the addition of sodium phenylbutyrate in 2009. In December 2013 he was switched to glycerol phenylbutyrate, and his metabolic stability was greatly improved over the following 7 months prior to liver transplant.
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In Vivo NMR Studies of the Brain with Hereditary or Acquired Metabolic Disorders. Neurochem Res 2015; 40:2647-85. [PMID: 26610379 DOI: 10.1007/s11064-015-1772-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 11/10/2015] [Accepted: 11/12/2015] [Indexed: 01/09/2023]
Abstract
Metabolic disorders, whether hereditary or acquired, affect the brain, and abnormalities of the brain are related to cellular integrity; particularly in regard to neurons and astrocytes as well as interactions between them. Metabolic disturbances lead to alterations in cellular function as well as microscopic and macroscopic structural changes in the brain with diabetes, the most typical example of metabolic disorders, and a number of hereditary metabolic disorders. Alternatively, cellular dysfunction and degeneration of the brain lead to metabolic disturbances in hereditary neurological disorders with neurodegeneration. Nuclear magnetic resonance (NMR) techniques allow us to assess a range of pathophysiological changes of the brain in vivo. For example, magnetic resonance spectroscopy detects alterations in brain metabolism and energetics. Physiological magnetic resonance imaging (MRI) detects accompanying changes in cerebral blood flow related to neurovascular coupling. Diffusion and T1/T2-weighted MRI detect microscopic and macroscopic changes of the brain structure. This review summarizes current NMR findings of functional, physiological and biochemical alterations within a number of hereditary and acquired metabolic disorders in both animal models and humans. The global view of the impact of these metabolic disorders on the brain may be useful in identifying the unique and/or general patterns of abnormalities in the living brain related to the pathophysiology of the diseases, and identifying future fields of inquiry.
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Pacheco-Colón I, Washington SD, Sprouse C, Helman G, Gropman AL, VanMeter JW. Reduced Functional Connectivity of Default Mode and Set-Maintenance Networks in Ornithine Transcarbamylase Deficiency. PLoS One 2015; 10:e0129595. [PMID: 26067829 PMCID: PMC4466251 DOI: 10.1371/journal.pone.0129595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 05/11/2015] [Indexed: 12/21/2022] Open
Abstract
Background and Purpose Ornithine transcarbamylase deficiency (OTCD) is an X-chromosome linked urea cycle disorder (UCD) that causes hyperammonemic episodes leading to white matter injury and impairments in executive functioning, working memory, and motor planning. This study aims to investigate differences in functional connectivity of two resting-state networks—default mode and set-maintenance—between OTCD patients and healthy controls. Methods Sixteen patients with partial OTCD and twenty-two control participants underwent a resting-state scan using 3T fMRI. Combining independent component analysis (ICA) and region-of-interest (ROI) analyses, we identified the nodes that comprised each network in each group, and assessed internodal connectivity. Results Group comparisons revealed reduced functional connectivity in the default mode network (DMN) of OTCD patients, particularly between the anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC) node and bilateral inferior parietal lobule (IPL), as well as between the ACC/mPFC node and the posterior cingulate cortex (PCC) node. Patients also showed reduced connectivity in the set-maintenance network, especially between right anterior insula/frontal operculum (aI/fO) node and bilateral superior frontal gyrus (SFG), as well as between the right aI/fO and ACC and between the ACC and right SFG. Conclusion Internodal functional connectivity in the DMN and set-maintenance network is reduced in patients with partial OTCD compared to controls, most likely due to hyperammonemia-related white matter damage. Because several of the affected areas are involved in executive functioning, it is postulated that this reduced connectivity is an underlying cause of the deficits OTCD patients display in this cognitive domain.
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Affiliation(s)
- Ileana Pacheco-Colón
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurology, Georgetown University Medical Center, Washington, DC, United States of America
- * E-mail:
| | - Stuart D. Washington
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurology, Georgetown University Medical Center, Washington, DC, United States of America
| | - Courtney Sprouse
- Department of Neurogenetics, Children’s National Health System, Washington, DC, United States of America
- George Washington University of the Health Sciences, Washington, DC, United States of America
| | - Guy Helman
- Department of Neurogenetics, Children’s National Health System, Washington, DC, United States of America
| | - Andrea L. Gropman
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurogenetics, Children’s National Health System, Washington, DC, United States of America
- George Washington University of the Health Sciences, Washington, DC, United States of America
- Medical Genetics Branch, NHGRI, National Institutes of Health, Bethesda, Maryland, United States of America
| | - John W. VanMeter
- Center for Functional and Molecular Imaging, Georgetown University, Washington, DC, United States of America
- Department of Neurology, Georgetown University Medical Center, Washington, DC, United States of America
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Prasun P, Altinok D, Misra VK. Ornithine transcarbamylase deficiency presenting with acute reversible cortical blindness. J Child Neurol 2015; 30:782-5. [PMID: 24850570 DOI: 10.1177/0883073814535490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 04/14/2014] [Indexed: 11/17/2022]
Abstract
Acute focal neurologic deficits are a rare but known presentation of ornithine transcarbamylase deficiency, particularly in females. We describe here a 6-year-old girl with newly diagnosed ornithine transcarbamylase deficiency who presents with an episode of acute cortical blindness lasting for 72 hours in the absence of hyperammonemia. Her symptoms were associated with a subcortical low-intensity lesion with overlying cortical hyperintensity on fluid-attenuated inversion recovery magnetic resonance imaging (MRI) of the occipital lobes. Acute reversible vision loss with these MRI findings is an unusual finding in patients with ornithine transcarbamylase deficiency. Our findings suggest a role for oxidative stress and aberrant glutamine metabolism in the acute clinical features of ornithine transcarbamylase deficiency even in the absence of hyperammonemia.
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Affiliation(s)
- Pankaj Prasun
- Division of Genetics & Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, USA
| | - Deniz Altinok
- Pediatric Imaging, Children's Hospital of Michigan, Detroit, MI, USA
| | - Vinod K Misra
- Division of Genetics & Metabolic Disorders, Children's Hospital of Michigan, Detroit, MI, USA
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Intracranial Pressure Monitoring Demonstrates that Cerebral Edema Is Not Correlated to Hyperammonemia in a Child with Ornithine Transcarbamylase Deficiency. JIMD Rep 2015; 27:55-62. [DOI: 10.1007/8904_2015_486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/31/2015] [Accepted: 07/15/2015] [Indexed: 10/23/2022] Open
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Abstract
Glycerol phenylbutyrate (GPB) is a new generation ammonia scavenger drug that was recently approved by the US FDA for chronic management in patients with urea cycle defect disorders after multicenter clinical trials. GPB is composed of three molecules of phenylbutyrate (PB) that are esterified to a glycerol backbone. The active agent, phenylacetate, is generated through multiple metabolic steps including hydrolysis in the small intestine by pancreatic triglyceride lipases. Its pharmacokinetic pattern is characterized by a slower release of the active metabolite than unconjugated PB, which contributes to superior ammonia control and fewer episodes of hyperammonemia. GPB is well tolerated with fewer gastrointestinal complications compared with sodium benzoate or PB. These unique features suggest that it may enhance adherence and, potentially, in improved outcomes in urea cycle disorder patients. GPB may have therapeutic potential in additional conditions such as chronic hepatic encephalopathy or other inherited metabolic disorders.
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Affiliation(s)
- Kimihiko Oishi
- a Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1497, New York, NY 10029, USA
- b Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1497, New York, NY 10029, USA
| | - George A Diaz
- a Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1497, New York, NY 10029, USA
- b Department of Pediatrics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1497, New York, NY 10029, USA
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Pacheco-Colón I, Fricke S, VanMeter J, Gropman AL. Advances in urea cycle neuroimaging: Proceedings from the 4th International Symposium on urea cycle disorders, Barcelona, Spain, September 2013. Mol Genet Metab 2014; 113:118-26. [PMID: 25066103 PMCID: PMC4177962 DOI: 10.1016/j.ymgme.2014.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 05/10/2014] [Indexed: 11/20/2022]
Abstract
Our previous imaging research performed as part of a Urea Cycle Rare Disorders Consortium (UCRDC) grant, has identified specific biomarkers of neurologic injury in ornithine transcarbamylase deficiency, OTCD. While characterization of mutations can be achieved in most cases, this information does not necessarily predict the severity of the underlying neurological syndrome. The biochemical consequences of any mutation may be modified additionally by a large number of factors, including contributions of other enzymes and transport systems that mediate flux through the urea cycle, diet and other environmental factors. These factors likely vary from one patient to another, and they give rise to heterogeneity of clinical severity. Affected cognitive domains include non-verbal learning, fine motor processing, reaction time, visual memory, attention, and executive function. Deficits in these capacities may be seen in symptomatic patients, as well as asymptomatic carriers with normal IQ and correlate with variances in brain structure and function in these patients. Using neuroimaging we can identify biomarkers that reflect the downstream impact of UCDs on cognition. This manuscript is a summary of the presentation from the 4th International Consortium on urea cycle disorders held in, Barcelona, Spain, September 2, 2014.
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Affiliation(s)
| | - Stanley Fricke
- Children's National Medical, USA; George Washington University, USA
| | - John VanMeter
- Center for Functional and Molecular Imaging, Georgetown University, USA
| | - Andrea L Gropman
- Center for Functional and Molecular Imaging, Georgetown University, USA; Children's National Medical, USA; George Washington University, USA.
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Krishna SH, McKinney AM, Lucato LT. Congenital Genetic Inborn Errors of Metabolism Presenting as an Adult or Persisting Into Adulthood: Neuroimaging in the More Common or Recognizable Disorders. Semin Ultrasound CT MR 2014; 35:160-91. [DOI: 10.1053/j.sult.2013.10.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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22
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Abstract
Magnetic resonance spectroscopy (MRS) is indicated in the imaging protocol of the patient with epilepsy to screen for metabolic derangements such as inborn errors of metabolism and to characterize masses that may be equivocal on conventional magnetic resonance imaging for dysplasia versus neoplasia. Single-voxel MRS with echo time of 35 milliseconds may be used for this purpose as a quick screening tool in the epilepsy imaging protocol. MRS is useful in the evaluation of both focal and generalized epilepsy.
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Lichter-Konecki U, Nadkarni V, Moudgil A, Cook N, Poeschl J, Meyer MT, Dimmock D, Baumgart S. Feasibility of adjunct therapeutic hypothermia treatment for hyperammonemia and encephalopathy due to urea cycle disorders and organic acidemias. Mol Genet Metab 2013; 109:354-9. [PMID: 23791307 DOI: 10.1016/j.ymgme.2013.05.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/20/2013] [Accepted: 05/20/2013] [Indexed: 01/06/2023]
Abstract
BACKGROUND Children with urea cycle disorders (UCDs) or organic acidemias (OAs) and acute hyperammonemia and encephalopathy are at great risk for neurological injury, developmental delay, intellectual disability, and death. Nutritional support, intravenous alternative pathway therapy, and dialysis are used to treat severe hyperammonemia associated with UCDs and nutritional support and dialysis are used to treat severe hyperammonemia in OAs. Brain protective treatment while therapy is initiated may improve neurological and cognitive function for the lifetime of the child. Animal experiments and small clinical trials in hepatic encephalopathy caused by acute liver failure suggest that therapeutic hypothermia provides neuroprotection in hyperammonemia associated encephalopathy. We report results of an ongoing pilot study that assesses if whole body cooling during rescue treatment of neonates with acute hyperammonemia and encephalopathy is feasible and can be conducted safely. METHODS Adjunct whole body therapeutic hypothermia was conducted in addition to standard treatment in acutely encephalopathic, hyperammonemic neonates with UCDs and OAs requiring dialysis. Therapeutic hypothermia was initiated using cooling blankets as preparations for dialysis were underway. Similar to standard therapeutic hypothermia treatment for neonatal hypoxic ischemic encephalopathy, patients were maintained at 33.5°C±1°C for 72h, they were then slowly rewarmed by 0.5°C every 3h over 18h. In addition data of age-matched historic controls were collected for comparison. RESULTS Seven patients were cooled using the pilot study protocol and data of seven historic controls were reviewed. All seven patients survived the initial rescue and cooling treatment, 6 patients were discharged home 2-4weeks after hospitalization, five of them feeding orally. The main complication observed in a majority of patients was hypotension. CONCLUSION Adjunct therapeutic hypothermia for neonates with UCDs and OAs receiving standard treatment was feasible and could be conducted safely in pediatric and neonatal intensive care units experienced in the application of therapeutic hypothermia in critically ill neonates. However, including adjunct therapeutic hypothermia in the already involved treatment regimen of critically ill patients with hyperammonemia and encephalopathy adds to the complexity of care and should not be done unless it is proven efficacious in a randomized clinical trial.
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MESH Headings
- Adolescent
- Child
- Child, Preschool
- Developmental Disabilities/complications
- Developmental Disabilities/pathology
- Developmental Disabilities/therapy
- Humans
- Hyperammonemia/pathology
- Hyperammonemia/therapy
- Hypothermia, Induced
- Hypoxia-Ischemia, Brain/complications
- Hypoxia-Ischemia, Brain/drug therapy
- Hypoxia-Ischemia, Brain/pathology
- Infant
- Infant, Newborn
- Pilot Projects
- Urea/metabolism
- Urea Cycle Disorders, Inborn/complications
- Urea Cycle Disorders, Inborn/genetics
- Urea Cycle Disorders, Inborn/pathology
- Urea Cycle Disorders, Inborn/therapy
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Affiliation(s)
- Uta Lichter-Konecki
- Division Genetics & Metabolism, Children's National Medical Center, Dept. of Pediatrics, George Washington University MC, Washington, DC 20010, USA.
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Gropman AL, Prust M, Breeden A, Fricke S, VanMeter J. Urea cycle defects and hyperammonemia: effects on functional imaging. Metab Brain Dis 2013; 28:269-75. [PMID: 23149878 PMCID: PMC3594356 DOI: 10.1007/s11011-012-9348-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 10/21/2012] [Indexed: 11/25/2022]
Abstract
The urea-cycle disorders (UCDs) are a group of congenital enzyme and carrier deficiencies predisposing to hyperammonemia (HA). HA causes changes in the central nervous system (CNS) including alterations of neurotransmitter function, cell volume, and energy deprivation ultimately leading to cerebral edema. Neuropathological findings of UCDs primarily reflect changes in astrocyte morphology. Neurological features accompanying acute HA include changes in behavior and consciousness in the short term, and potential for impairments in memory and executive function as long-term effects. Plasma measures of ammonia and glutamine, although useful for clinical monitoring, prove poor markers of CNS function. Multimodal neuroimaging has potential to investigate impact on cognitive function by interrogating neural networks, connectivity and biochemistry. As neuroimaging methods become increasingly sophisticated, they will play a critical role in clinical monitoring and treatment of metabolic disease. We describe our findings in UCDs; with focus on Ornithine Transcarbamylase deficiency (OTCD) the only X linked UCD.
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Affiliation(s)
- Andrea L Gropman
- Department of Neurology, Children's National Medical Center, George Washington University of Health Sciences, 111 Michigan Avenue, NW, Washington, DC 20010, USA.
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Diaz GA, Krivitzky LS, Mokhtarani M, Rhead W, Bartley J, Feigenbaum A, Longo N, Berquist W, Berry SA, Gallagher R, Lichter-Konecki U, Bartholomew D, Harding CO, Cederbaum S, McCandless SE, Smith W, Vockley G, Bart SA, Korson MS, Kronn D, Zori R, Merritt JL, C S Nagamani S, Mauney J, Lemons C, Dickinson K, Moors TL, Coakley DF, Scharschmidt BF, Lee B. Ammonia control and neurocognitive outcome among urea cycle disorder patients treated with glycerol phenylbutyrate. Hepatology 2013; 57:2171-9. [PMID: 22961727 PMCID: PMC3557606 DOI: 10.1002/hep.26058] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/15/2012] [Indexed: 02/02/2023]
Abstract
UNLABELLED Glycerol phenylbutyrate is under development for treatment of urea cycle disorders (UCDs), rare inherited metabolic disorders manifested by hyperammonemia and neurological impairment. We report the results of a pivotal Phase 3, randomized, double-blind, crossover trial comparing ammonia control, assessed as 24-hour area under the curve (NH3 -AUC0-24hr ), and pharmacokinetics during treatment with glycerol phenylbutyrate versus sodium phenylbutyrate (NaPBA) in adult UCD patients and the combined results of four studies involving short- and long-term glycerol phenylbutyrate treatment of UCD patients ages 6 and above. Glycerol phenylbutyrate was noninferior to NaPBA with respect to ammonia control in the pivotal study, with mean (standard deviation, SD) NH3 -AUC0-24hr of 866 (661) versus 977 (865) μmol·h/L for glycerol phenylbutyrate and NaPBA, respectively. Among 65 adult and pediatric patients completing three similarly designed short-term comparisons of glycerol phenylbutyrate versus NaPBA, NH3 -AUC0-24hr was directionally lower on glycerol phenylbutyrate in each study, similar among all subgroups, and significantly lower (P < 0.05) in the pooled analysis, as was plasma glutamine. The 24-hour ammonia profiles were consistent with the slow-release behavior of glycerol phenylbutyrate and better overnight ammonia control. During 12 months of open-label glycerol phenylbutyrate treatment, average ammonia was normal in adult and pediatric patients and executive function among pediatric patients, including behavioral regulation, goal setting, planning, and self-monitoring, was significantly improved. CONCLUSION Glycerol phenylbutyrate exhibits favorable pharmacokinetics and ammonia control relative to NaPBA in UCD patients, and long-term glycerol phenylbutyrate treatment in pediatric UCD patients was associated with improved executive function (ClinicalTrials.gov NCT00551200, NCT00947544, NCT00992459, NCT00947297). (HEPATOLOGY 2012).
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Affiliation(s)
- George A Diaz
- Mount Sinai School of Medicine, Department of Genetics and Genomic Sciences, Department of Pediatrics, New York, NY, USA
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Abstract
Many inborn errors of metabolism (IEMs) are associated with irreversible brain injury. For many, it is unclear how metabolite intoxication or substrate depletion accounts for the specific neurologic findings observed. IEM-associated brain injury patterns are characterized by whether the process involves gray matter, white matter, or both, and beyond that, whether subcortical or cortical gray matter nuclei are involved. Despite global insults, IEMs may result in selective injury to deep gray matter nuclei or white matter. This manuscript reviews the neuro-imaging patterns of neural injury in selected disorders of metabolism involving small molecule and macromolecular disorders (ie, Phenylketonuria, urea cycle disorders, and maple syrup urine disease) and discusses the contribution of diet and nutrition to the prevention or exacerbation of injury in selected inborn metabolic disorders. Where known, a review of the roles of individual differences in blood-brain permeability and transport mechanisms in the etiology of these disorders will be discussed.
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Affiliation(s)
- Andrea L. Gropman
- Departments of Pediatrics and Neurology, Children’s National Medical Center and the George Washington University of the Health Sciences, Washington, DC
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Degos B, Daelman L, Huberfeld G, Meppiel E, Rabier D, Galanaud D, Magis AS, Lyon-Caen O, Samuel D, Sedel F. Portosystemic shunts: an underdiagnosed but treatable cause of neurological and psychiatric disorders. J Neurol Sci 2012; 321:58-64. [PMID: 22906583 DOI: 10.1016/j.jns.2012.07.050] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 07/20/2012] [Accepted: 07/20/2012] [Indexed: 12/19/2022]
Abstract
Portosystemic shunts (PSS) remain an unrecognized cause of neurological or psychiatric disorders. Here we report 5 patients with neuropsychiatric presentations of PSS. Main presentations encompassed progressive Parkinsonism, organic psychosis, recurrent coma, recurrent delusion, cognitive decline and posterior cortical atrophy. None of our patients had a known history of liver disease and laboratory analyses of liver function were normal or only slightly perturbed. Only 16 similar cases of PSS revealed by neurological or psychiatric symptoms were found in the English literature. Clinical presentations were similar to our patients but asterixis, cerebellar symptoms and spastic paraparesis were noticed in some cases. EEG could be normal or could show non specific slow waves or even, rarely, triphasic slow waves. The most frequent and specific diagnostic features included hyperammonemia, abnormal brain magnetic resonance spectroscopy and visualization of the shunts by ultrasonography or abdominal imaging techniques. Therefore, in otherwise unexplained neuropsychiatric disturbances, ammonia should be routinely measured and, if elevated, a dedicated gastroenterologist or an expert radiologist should be consulted for potential PSS examination. Treatment of the shunts or of the hyperammonemia resulted in marked neurological or psychiatric improvement in all cases.
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Affiliation(s)
- Bertrand Degos
- Department of Neurology, Salpêtrière Hospital, Assistance Publique Hôpitaux de Paris, France.
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Boenzi S, Pastore A, Martinelli D, Goffredo BM, Boiani A, Rizzo C, Dionisi-Vici C. Creatine metabolism in urea cycle defects. J Inherit Metab Dis 2012; 35:647-53. [PMID: 22644604 DOI: 10.1007/s10545-012-9494-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 04/26/2012] [Accepted: 04/28/2012] [Indexed: 12/12/2022]
Abstract
Creatine (Cr) and phosphocreatine play an essential role in energy storage and transmission. Maintenance of creatine pool is provided by the diet and by de novo synthesis, which utilizes arginine, glycine and s-adenosylmethionine as substrates. Three primary Cr deficiencies exists: arginine:glycine amidinotransferase deficiency, guanidinoacetate methyltransferase deficiency and the defect of Cr transporter SLC6A8. Secondary Cr deficiency is characteristic of ornithine-aminotransferase deficiency, whereas non-uniform Cr abnormalities have anecdotally been reported in patients with urea cycle defects (UCDs), a disease category related to arginine metabolism in which Cr must be acquired by de novo synthesis because of low dietary intake. To evaluate the relationships between ureagenesis and Cr synthesis, we systematically measured plasma Cr in a large series of UCD patients (i.e., OTC, ASS, ASL deficiencies, HHH syndrome and lysinuric protein intolerance). Plasma Cr concentrations in UCDs followed two different trends: patients with OTC and ASS deficiencies and HHH syndrome presented a significant Cr decrease, whereas in ASL deficiency and lysinuric protein intolerance Cr levels were significantly increased (23.5 vs. 82.6 μmol/L; p < 0.0001). This trend distribution appears to be regulated upon cellular arginine availability, highlighting its crucial role for both ureagenesis and Cr synthesis. Although decreased Cr contributes to the neurological symptoms in primary Cr deficiencies, still remains to be explored if an altered Cr metabolism may participate to CNS dysfunction also in patients with UCDs. Since arginine in most UCDs becomes a semi-essential aminoacid, measuring plasma Cr concentrations might be of help to optimize the dose of arginine substitution.
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Affiliation(s)
- Sara Boenzi
- Division of Metabolism and Research Unit of Metabolic Biochemistry, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy.
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Häberle J, Boddaert N, Burlina A, Chakrapani A, Dixon M, Huemer M, Karall D, Martinelli D, Crespo PS, Santer R, Servais A, Valayannopoulos V, Lindner M, Rubio V, Dionisi-Vici C. Suggested guidelines for the diagnosis and management of urea cycle disorders. Orphanet J Rare Dis 2012; 7:32. [PMID: 22642880 PMCID: PMC3488504 DOI: 10.1186/1750-1172-7-32] [Citation(s) in RCA: 362] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 04/06/2012] [Indexed: 12/11/2022] Open
Abstract
Urea cycle disorders (UCDs) are inborn errors of ammonia detoxification/arginine synthesis due to defects affecting the catalysts of the Krebs-Henseleit cycle (five core enzymes, one activating enzyme and one mitochondrial ornithine/citrulline antiporter) with an estimated incidence of 1:8.000. Patients present with hyperammonemia either shortly after birth (~50%) or, later at any age, leading to death or to severe neurological handicap in many survivors. Despite the existence of effective therapy with alternative pathway therapy and liver transplantation, outcomes remain poor. This may be related to underrecognition and delayed diagnosis due to the nonspecific clinical presentation and insufficient awareness of health care professionals because of disease rarity. These guidelines aim at providing a trans-European consensus to: guide practitioners, set standards of care and help awareness campaigns. To achieve these goals, the guidelines were developed using a Delphi methodology, by having professionals on UCDs across seven European countries to gather all the existing evidence, score it according to the SIGN evidence level system and draw a series of statements supported by an associated level of evidence. The guidelines were revised by external specialist consultants, unrelated authorities in the field of UCDs and practicing pediatricians in training. Although the evidence degree did hardly ever exceed level C (evidence from non-analytical studies like case reports and series), it was sufficient to guide practice on both acute and chronic presentations, address diagnosis, management, monitoring, outcomes, and psychosocial and ethical issues. Also, it identified knowledge voids that must be filled by future research. We believe these guidelines will help to: harmonise practice, set common standards and spread good practices with a positive impact on the outcomes of UCD patients.
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Affiliation(s)
- Johannes Häberle
- University Children’s Hospital Zurich and Children’s Research Centre, Zurich, 8032, Switzerland
| | - Nathalie Boddaert
- Radiologie Hopital Necker, Service Radiologie Pediatrique, 149 Rue De Sevres, Paris 15, 75015, France
| | - Alberto Burlina
- Department of Pediatrics, Division of Inborn Metabolic Disease, University Hospital Padua, Via Giustiniani 3, Padova, 35128, Italy
| | - Anupam Chakrapani
- Birmingham Children’s Hospital NHS Foundation Trust, Steelhouse Lane, Birmingham, B4 6NH, United Kingdom
| | - Marjorie Dixon
- Dietetic Department, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, WC1N 3JH, United Kingdom
| | - Martina Huemer
- Kinderabteilung, LKH Bregenz, Carl-Pedenz-Strasse 2, Bregenz, A-6900, Austria
| | - Daniela Karall
- University Children’s Hospital, Medical University Innsbruck, Anichstrasse 35, Innsbruck, 6020, Austria
| | - Diego Martinelli
- Division of Metabolism, Bambino Gesù Children’s Hospital, IRCCS, Piazza S. Onofrio 4, Rome, I-00165, Italy
| | | | - René Santer
- Universitätsklinikum Hamburg Eppendorf, Klinik für Kinder- und Jugendmedizin, Martinistr. 52, Hamburg, 20246, Germany
| | - Aude Servais
- Service de Néphrologie et maladies métaboliques adulte Hôpital Necker 149, rue de Sèvres, Paris, 75015, France
| | - Vassili Valayannopoulos
- Reference Center for Inherited Metabolic Disorders (MaMEA), Hopital Necker-Enfants Malades, 149 Rue de Sevres, Paris, 75015, France
| | - Martin Lindner
- University Children’s Hospital, Im Neuenheimer Feld 430, Heidelberg, 69120, Germany
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas (IBV-CSIC) and Centro de Investigación Biomédica en Red para Enfermedades Raras (CIBERER), C/ Jaume Roig 11, Valencia, 46010, Spain
| | - Carlo Dionisi-Vici
- Division of Metabolism, Bambino Gesù Children’s Hospital, IRCCS, Piazza S. Onofrio 4, Rome, I-00165, Italy
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Bireley WR, Van Hove JLK, Gallagher RC, Fenton LZ. Urea cycle disorders: brain MRI and neurological outcome. Pediatr Radiol 2012; 42:455-62. [PMID: 21989980 DOI: 10.1007/s00247-011-2253-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 08/17/2011] [Accepted: 08/22/2011] [Indexed: 01/09/2023]
Abstract
BACKGROUND Urea cycle disorders encompass several enzyme deficiencies that can result in cerebral damage, with a wide clinical spectrum from asymptomatic to severe. OBJECTIVE The goal of this study was to correlate brain MRI abnormalities in urea cycle disorders with clinical neurological sequelae to evaluate whether MRI abnormalities can assist in guiding difficult treatment decisions. MATERIALS AND METHODS We performed a retrospective chart review of patients with urea cycle disorders and symptomatic hyperammonemia. Brain MRI images were reviewed for abnormalities that correlated with severity of clinical neurological sequelae. RESULTS Our case series comprises six urea cycle disorder patients, five with ornithine transcarbamylase deficiency and one with citrullinemia type 1. The observed trend in distribution of brain MRI abnormalities as the severity of neurological sequelae increased was the peri-insular region first, extending into the frontal, parietal, temporal and, finally, the occipital lobes. There was thalamic restricted diffusion in three children with prolonged hyperammonemia. Prior to death, this site is typically reported to be spared in urea cycle disorders. CONCLUSION The pattern and extent of brain MRI abnormalities correlate with clinical neurological outcome in our case series. This suggests that brain MRI abnormalities may assist in determining prognosis and helping clinicians with subsequent treatment decisions.
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Affiliation(s)
- William R Bireley
- Department of Radiology, University of Colorado, 12631 E. 17th Ave., Aurora, CO 80045, USA.
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Gropman AL, Shattuck K, Prust MJ, Seltzer RR, Breeden AL, Hailu A, Rigas A, Hussain R, VanMeter J. Altered neural activation in ornithine transcarbamylase deficiency during executive cognition: an fMRI study. Hum Brain Mapp 2011; 34:753-61. [PMID: 22110002 DOI: 10.1002/hbm.21470] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 07/26/2011] [Accepted: 08/26/2011] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Ornithine transcarbamylase deficiency (OTCD) is an X-linked urea cycle disorder characterized by hyperammonemia resulting in white matter injury and impairments in working memory and executive cognition. OBJECTIVE To test for differences in BOLD signal activation between subjects with OTCD and healthy controls during a working memory task. DESIGN, SETTING AND PATIENTS Nineteen subjects with OTCD and 21 healthy controls participated in a case-control, IRB-approved study at Georgetown University Medical Center. INTERVENTION An N-back working memory task was performed in a block design using 3T functional magnetic resonance imaging. RESULTS In subjects with OTCD we observed increased BOLD signal in the right dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) relative to healthy age matched controls. CONCLUSIONS Increased neuronal activation in OTCD subjects despite equivalent task performance points to sub-optimal activation of the working memory network in these subjects, most likely reflecting damage caused by hyperammonemic events. These increases directly relate to our previous finding of reduced frontal white matter integrity in the superior extents of the corpus callosum; key hemispheric connections for these areas. Future studies using higher cognitive load are required to further characterize these effects.
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Affiliation(s)
- Andrea L Gropman
- Department of Neurology, Children's National Medical Center, Washington, DC 20010, USA.
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Prust MJ, Gropman AL, Hauser N. New frontiers in neuroimaging applications to inborn errors of metabolism. Mol Genet Metab 2011; 104:195-205. [PMID: 21778100 PMCID: PMC3758691 DOI: 10.1016/j.ymgme.2011.06.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Revised: 06/25/2011] [Accepted: 06/26/2011] [Indexed: 12/21/2022]
Abstract
Most inborn errors of metabolism (IEMs) are associated with potential for injury to the developing central nervous system resulting in chronic encephalopathy, though the etiopathophysiology of neurological injury have not been fully established in many disorders. Shared mechanisms can be envisioned such as oxidative injury due to over-activation of N-Methyl-d-Aspartate (NMDA) receptors with subsequent glutamatergic damage, but other causes such as energy depletion or inflammation are possible. Neuroimaging has emerged as a powerful clinical and research tool for studying the brain in a noninvasive manner. Several platforms exist to study neural networks underlying cognitive processes, white matter/myelin microstructure, and cerebral metabolism in vivo. The scope and limitations of these methods will be discussed in the context of valuable information they provide in the study and management of selected inborn errors of metabolism. This review is not meant to be an exhaustive coverage of diagnostic findings on MRI in multiple IEMs, but rather to illustrate how neuroimaging modalities beyond T1 and T2 images, can add depth to an understanding of the underlying brain changes evoked by the selected IEMs. Emphasis will be placed on techniques that are available in the clinical setting. Though technically complex, many of these modalities have moved - or soon will - to the clinical arena.
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Affiliation(s)
- Morgan J. Prust
- Department of Neurology, Children’s National Medical Center, Washington, D.C., USA
| | - Andrea L. Gropman
- Department of Neurology, Children’s National Medical Center, Washington, D.C., USA
- Medical Genetics Branch, National Human Genome Research Institute, USA
- Corresponding author at: Department of Neurology, Children’s National Medical Center, 111 Michigan Avenue, N.W., Washington, D.C. 20010, USA. Fax: +1 202 476 5226. (A.L. Gropman)
| | - Natalie Hauser
- Medical Genetics Branch, National Human Genome Research Institute, USA
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Clinical practice: the management of hyperammonemia. Eur J Pediatr 2011; 170:21-34. [PMID: 21165747 DOI: 10.1007/s00431-010-1369-2] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/22/2010] [Accepted: 11/24/2010] [Indexed: 01/25/2023]
Abstract
Hyperammonemia is a life-threatening condition which can affect patients at any age. Elevations of ammonia in plasma indicate its increased production and/or decreased detoxification. The hepatic urea cycle is the main pathway to detoxify ammonia; it can be defective due to an inherited enzyme deficiency or secondary to accumulated toxic metabolites or substrate depletion. Clinical signs and symptoms in hyperammonemia are unspecific but they are mostly neurological. Thus, in any unexplained change in consciousness or in any unexplained encephalopathy, hyperammonemia must be excluded as fast as possible. Any delay in recognition and start of treatment of hyperammonemia may have deleterious consequences for the patient. Treatment largely depends on the underlying cause but is, at least in pediatric patients, mainly aimed at establishing anabolism to avoid endogenous protein breakdown and amino acid imbalances. In addition, pharmacological treatment options exist to improve urea cycle function or to remove nitrogen, but their use depend on the underlying disorder. To improve the prognosis of acute hyperammonemia, an increased awareness of this condition is probably more needed than anything else. Likewise, the immediate start of appropriate therapy is of utmost importance. This review focuses on a better understanding of factors leading to ammonia elevations and on practical aspects related to diagnosis and treatment in order to improve clinical management of hyperammonemia.
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Brajon D, Carassou P, Pruna L, Feillet F, Kaminsky P. [Ornithine transcarbamylase deficiency in adult]. Rev Med Interne 2010; 31:709-11. [PMID: 20570026 DOI: 10.1016/j.revmed.2010.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 01/11/2010] [Accepted: 02/06/2010] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Ornithine transcarbamylase (OTC) deficiency is a X-linked inherited disorder characterized by hyperammoniemic encephalopathy in male neonates. However, there is an increased evidence of late-onset disease, including in adults. CASE REPORTS A 23-year-old woman presented with vomiting, somnolence, confusion and hyperammonemia. Familial history revealed OTC deficiency in three brothers and one sister, but urinary orotic acid level was normal at birth in the reported patient who therefore was considered as mutation-free. The mother was asymptomatic but had cognitive defect and moderate mental deficiency. Molecular biology demonstrated that both our patient and her mother were heterozygous for complete OCT deletion. CONCLUSION OCT deficiency could be diagnosed in adult patients at any age and clinical features are various, including hyperammonemic encephalopathy, psychiatric disorders or mental deficiency.
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Affiliation(s)
- D Brajon
- Médecine interne orientée vers les maladies orphelines et systémiques, Tour Drouet, hôpitaux de Brabois, CHU de Nancy, 54511 Vandœuvre cedex, France
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Abstract
Urea cycle disorders (UCD) represent a group of rare inborn errors of metabolism that carry a high risk of mortality and neurological morbidity resulting from the effects of accumulation of ammonia and other biochemical intermediates. These disorders result from single gene defects involved in the detoxification pathway of ammonia to urea. UCD include deficiencies in any of the six enzymes and two membrane transporters involved in urea biosynthesis. It has previously been reported that approximately half of infants who present with hyperammonemic coma in the newborn period die of cerebral edema; and those who survive 3days or more of coma invariably have intellectual disability [1]. In children with partial defects there is an association between the number and severity of recurrent hyperammonemic (HA) episodes (i.e. with or without coma) and subsequent cognitive and neurologic deficits [2]. However, the effects of milder or subclinical HA episodes on the brain are largely unknown. This review discusses the results of neuroimaging studies performed as part of the NIH funded Rare Diseases Clinical Research Center in Urea Cycle Disorders and focuses on biomarkers of brain injury in ornithine transcarbamylase deficiency (OTCD). We used anatomic imaging, functional magnetic resonance imaging (fMRI), diffusion-tensor imaging (DTI), and (1)H/(13)C magnetic resonance spectroscopy (MRS) to study clinically stable adults with partial OTCD. This allowed us to determine alterations in brain biochemistry associated with changes in cell volume and osmolarity and permitted us to identify brain biomarkers of HA. We found that white matter tracts underlying specific pathways involved in working memory and executive function are altered in subjects with OTCD (as measured by DTI), including those heterozygous women who were previously considered asymptomatic. An understanding of the pathogenesis of brain injury in UCD is likely to advance our knowledge of more common disorders of liver dysfunction.
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Affiliation(s)
- Andrea Gropman
- Department of Neurology, Children's National Medical Center, Center for Neuroscience and Behavioral Medicine, Washington, DC 20010, USA.
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Gropman AL, Sailasuta N, Harris KC, Abulseoud O, Ross BD. Ornithine transcarbamylase deficiency with persistent abnormality in cerebral glutamate metabolism in adults. Radiology 2009; 252:833-41. [PMID: 19567648 DOI: 10.1148/radiol.2523081878] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To determine cerebral glutamate turnover rate in partial-ornithine transcarbamylase deficiency (OTCD) patients by using carbon 13 ((13)C) magnetic resonance (MR) spectroscopy. MATERIALS AND METHODS The study was performed with approval of the institutional review board, in compliance with HIPAA regulations, and with written informed consent of the subjects. MR imaging, hydrogen 1 ((1)H) MR spectroscopy, and (13)C MR spectroscopy were performed at 1.5 T in 10 subjects, six patients with OTCD and four healthy control subjects, who were in stable condition. Each received intravenous (13)C-glucose (0.2 g/kg), C1 or C2 position, as a 15-minute bolus. Cerebral metabolites were determined with proton decoupling in a parieto-occipital region (n = 9) and without proton decoupling in a frontal region (n = 1) during 60-120 minutes. RESULTS Uptake and removal of cerebral glucose ([1-(13)C]-glucose or [2-(13)C]-glucose) were comparable in healthy control subjects and subjects with OTCD (P = .1). Glucose C1 was metabolized to glutamate C4 and glucose C2 was metabolized to glutamate C5 at comparable rates, both of which were significantly reduced in OTCD (combined, P = .04). No significant differences in glutamine formation were found in subjects with OTCD (P = .1). [2-(13)C]-glucose and its metabolic products were observed in anterior cingulate gyrus without proton decoupling in one subject with OTCD. CONCLUSION Treatments that improve cerebral glucose metabolism and glutamate neurotransmission may improve neurologic outcome in patients with OTCD, in whom prevention and treatment of hyperammonemic episodes appear to be insufficient.
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Affiliation(s)
- Andrea L Gropman
- Department of Neurology, Children's National Medical Center, Washington, DC, USA
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