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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] [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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2
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Diaz GA, Bechter M, Cederbaum SD. The role and control of arginine levels in arginase 1 deficiency. J Inherit Metab Dis 2023; 46:3-14. [PMID: 36175366 PMCID: PMC10091968 DOI: 10.1002/jimd.12564] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/22/2022] [Accepted: 09/27/2022] [Indexed: 01/19/2023]
Abstract
Arginase 1 Deficiency (ARG1-D) is a rare urea cycle disorder that results in persistent hyperargininemia and a distinct, progressive neurologic phenotype involving developmental delay, intellectual disability, and spasticity, predominantly affecting the lower limbs and leading to mobility impairment. Unlike the typical presentation of other urea cycle disorders, individuals with ARG1-D usually appear healthy at birth and hyperammonemia is comparatively less severe and less common. Clinical manifestations typically begin to develop in early childhood in association with high plasma arginine levels, with hyperargininemia (and not hyperammonemia) considered to be the primary driver of disease sequelae. Nearly five decades of clinical experience with ARG1-D and empirical studies in genetically manipulated models have generated a large body of evidence that, when considered in aggregate, implicates arginine directly in disease pathophysiology. Severe dietary protein restriction to minimize arginine intake and diversion of ammonia from the urea cycle are the mainstay of care. Although this approach does reduce plasma arginine and improve patients' cognitive and motor/mobility manifestations, it is inadequate to achieve and maintain sufficiently low arginine levels and prevent progression in the long term. This review presents a comprehensive discussion of the clinical and scientific literature, the effects and limitations of the current standard of care, and the authors' perspectives regarding the past, current, and future management of ARG1-D.
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Affiliation(s)
- George A Diaz
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Stephen D Cederbaum
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
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3
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Duff C, Baruteau J. Modelling urea cycle disorders using iPSCs. NPJ Regen Med 2022; 7:56. [PMID: 36163209 PMCID: PMC9513077 DOI: 10.1038/s41536-022-00252-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 08/10/2022] [Indexed: 11/23/2022] Open
Abstract
The urea cycle is a liver-based pathway enabling disposal of nitrogen waste. Urea cycle disorders (UCDs) are inherited metabolic diseases caused by deficiency of enzymes or transporters involved in the urea cycle and have a prevalence of 1:35,000 live births. Patients present recurrent acute hyperammonaemia, which causes high rate of death and neurological sequelae. Long-term therapy relies on a protein-restricted diet and ammonia scavenger drugs. Currently, liver transplantation is the only cure. Hence, high unmet needs require the identification of effective methods to model these diseases to generate innovative therapeutics. Advances in both induced pluripotent stem cells (iPSCs) and genome editing technologies have provided an invaluable opportunity to model patient-specific phenotypes in vitro by creating patients’ avatar models, to investigate the pathophysiology, uncover novel therapeutic targets and provide a platform for drug discovery. This review summarises the progress made thus far in generating 2- and 3-dimensional iPSCs models for UCDs, the challenges encountered and how iPSCs offer future avenues for innovation in developing the next-generation of therapies for UCDs.
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Affiliation(s)
- Claire Duff
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Julien Baruteau
- Genetics and Genomic Medicine Department, Great Ormond Street Institute of Child Health, University College London, London, UK. .,National Institute of Health Research Great Ormond Street Biomedical Research Centre, London, UK. .,Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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Bin Sawad A, Jackimiec J, Bechter M, Trucillo A, Lindsley K, Bhagat A, Uyei J, Diaz GA. Epidemiology, methods of diagnosis, and clinical management of patients with arginase 1 deficiency (ARG1-D): A systematic review. Mol Genet Metab 2022; 137:153-163. [PMID: 36049366 DOI: 10.1016/j.ymgme.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/18/2022] [Accepted: 08/20/2022] [Indexed: 11/19/2022]
Abstract
BACKGROUND Arginase 1 Deficiency (ARG1-D) is a rare, progressive, metabolic disorder that is characterized by devastating manifestations driven by elevated plasma arginine levels. It typically presents in early childhood with spasticity (predominately affecting the lower limbs), mobility impairment, seizures, developmental delay, and intellectual disability. This systematic review aims to identify and describe the published evidence outlining the epidemiology, diagnosis methods, measures of disease progression, clinical management, and outcomes for ARG1-D patients. METHODS A comprehensive literature search across multiple databases such as MEDLINE, Embase, and a review of clinical studies in ClinicalTrials.gov (with results reported) was carried out per PRISMA guidelines on 20 April 2020 with no date restriction. Pre-defined eligibility criteria were used to identify studies with data specific to patients with ARG1-D. Two independent reviewers screened records and extracted data from included studies. Quality was assessed using the modified Newcastle-Ottawa Scale for non-comparative studies. RESULTS Overall, 55 records reporting 40 completed studies and 3 ongoing studies were included. Ten studies reported the prevalence of ARG1-D in the general population, with a median of 1 in 1,000,000. Frequently reported diagnostic methods included genetic testing, plasma arginine levels, and red blood cell arginase activity. However, routine newborn screening is not universally available, and lack of disease awareness may prevent early diagnosis or lead to misdiagnosis, as the disease has overlapping symptomology with other diseases, such as cerebral palsy. Common manifestations reported at time of diagnosis and assessed for disease progression included spasticity (predominately affecting the lower limbs), mobility impairment, developmental delay, intellectual disability, and seizures. Severe dietary protein restriction, essential amino acid supplementation, and nitrogen scavenger administration were the most commonly reported treatments among patients with ARG1-D. Only a few studies reported meaningful clinical outcomes of these interventions on intellectual disability, motor function and adaptive behavior assessment, hospitalization, or death. The overall quality of included studies was assessed as good according to the Newcastle-Ottawa Scale. CONCLUSIONS Although ARG1-D is a rare disease, published evidence demonstrates a high burden of disease for patients. The current standard of care is ineffective at preventing disease progression. There remains a clear need for new treatment options as well as improved access to diagnostics and disease awareness to detect and initiate treatment before the onset of clinical manifestations to potentially enable more normal development, improve symptomatology, or prevent disease progression.
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Affiliation(s)
| | | | | | | | | | | | | | - George A Diaz
- Division of Medical Genetics and Genomics in the Department of Genetics and Genomic Sciences at the Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Khoja S, Liu XB, Truong B, Nitzahn M, Lambert J, Eliav A, Nasser E, Randolph E, Burke KE, White R, Zhu X, Martini PG, Nissim I, Cederbaum SD, Lipshutz GS. Intermittent lipid nanoparticle mRNA administration prevents cortical dysmyelination associated with arginase deficiency. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 28:859-874. [PMID: 35694211 PMCID: PMC9156989 DOI: 10.1016/j.omtn.2022.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 04/22/2022] [Indexed: 11/28/2022]
Abstract
Arginase deficiency is associated with prominent neuromotor features, including spastic diplegia, clonus, and hyperreflexia; intellectual disability and progressive neurological decline are other signs. In a constitutive murine model, we recently described leukodystrophy as a significant component of the central nervous system features of arginase deficiency. In the present studies, we sought to examine if the administration of a lipid nanoparticle carrying human ARG1 mRNA to constitutive knockout mice could prevent abnormalities in myelination associated with arginase deficiency. Imaging of the cingulum, striatum, and cervical segments of the corticospinal tract revealed a drastic reduction of myelinated axons; signs of degenerating axons were also present with thin myelin layers. Lipid nanoparticle/ARG1 mRNA administration resulted in both light and electron microscopic evidence of a dramatic recovery of myelin density compared with age-matched controls; oligodendrocytes were seen to be extending processes to wrap many axons. Abnormally thin myelin layers, when myelination was present, were resolved with intermittent mRNA administration, indicative of not only a greater density of myelinated axons but also an increase in the thickness of the myelin sheath. In conclusion, lipid nanoparticle/ARG1 mRNA administration in arginase deficiency prevents the associated leukodystrophy and restores normal oligodendrocyte function.
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Affiliation(s)
- Suhail Khoja
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Xiao-Bo Liu
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Brian Truong
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Matthew Nitzahn
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Jenna Lambert
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Adam Eliav
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Eram Nasser
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Emma Randolph
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | | | - Rebecca White
- Moderna Inc., 200 Technology Square, Cambridge, MA 02139, USA
| | - Xuling Zhu
- Moderna Inc., 200 Technology Square, Cambridge, MA 02139, USA
| | | | - Itzhak Nissim
- Division of Metabolism and Human Genetics, The Children Hospital of Philadelphia and The Department of Biochemistry and Biophysics, Perlman School of Medicine, Philadelphia, PA 19104, USA
| | - Stephen D. Cederbaum
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center at UCLA, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Gerald S. Lipshutz
- Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Department of Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
- Intellectual and Developmental Disabilities Research Center at UCLA, Los Angeles, CA 90095, USA
- Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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6
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Cui B, Wei L, Sun LY, Qu W, Zeng ZG, Liu Y, Zhu ZJ. The effect of liver transplantation for argininemia-the largest experiences in a single center. Transl Pediatr 2022; 11:495-504. [PMID: 35558983 PMCID: PMC9085954 DOI: 10.21037/tp-21-576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 01/27/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Argininemia, a rare urea cycle disorder resulting from an arginase-1 deficiency, is characterized by a progressive spastic paraplegia. While advances in diagnosis and treatment have increased the management of this condition, not all symptoms are resolved in response to traditional therapies. Interestingly, there exist some rare reports on the use of liver transplantation (LT) for the treatment of argininemia. METHODS We conducted a retrospective study of eleven patients with argininemia receiving a LT as performed at our center over the period from January 2015 to November 2019. These patients were included due to their poor responses to protein restriction diets and alternative therapies of nitrogen scavengers. Detailed information on coagulation, liver function, histopathological and morphological examination of liver samples, and other clinical presentations were extracted from these patients. A grading scale was used for evaluating the neurological status, classification of physical growth and quality of life of these patients in response to the LT. RESULTS Prior to LT, high levels of arginine were detected in all of argininemia patients and liver enzymes were elevated in nine of those patients. Nine patients presented with coagulation dysfunction without bleeding symptoms. Spastic paraplegia, irritability, intellectual developmental disability, and growth deficits were hallmarks of these nine patients, while four patients showed repeated, generalized tonic-clonic seizures before the operation. Seven novel mutations were found in these patients. The indication for LT in this series of patients was a presentation of progressive neurological impairments. After LT, the coagulation index and plasma arginine levels returned to normal and episodes of seizure were controlled in four patients. To date, all patients have survived and their LT has resulted a restoration of arginine metabolism and liver function, along with preventing further neurological deterioration, all of which provided an opportunity for future recuperation. Overall, the neurological status, growth deficits and quality of life were all significantly improved after LT with no evidence of severe complications. CONCLUSIONS LT can serve as an effective treatment for argininemia in patients who respond poorly to traditional therapy. An early intervention of LT should be conducted in these patients to prevent neurological damage and improve their quality of life.
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Affiliation(s)
- Bin Cui
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Lin Wei
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Li-Ying Sun
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China.,Department of Critical Liver Diseases, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Wei Qu
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Zhi-Gui Zeng
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Ying Liu
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Zhi-Jun Zhu
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
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7
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Selenium protects against the likelihood of fetal neural tube defects partly via the arginine metabolic pathway. Clin Nutr 2022; 41:838-846. [DOI: 10.1016/j.clnu.2022.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 01/26/2022] [Accepted: 02/10/2022] [Indexed: 11/22/2022]
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8
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Jiang XW, Yu WH, Wang Y, Xiong ZL, Ma XL, Zhou C, Huo MH. Acetyl-11-keto-beta-boswellic acid promotes sciatic nerve repair after injury: molecular mechanism. Neural Regen Res 2022; 17:2778-2784. [PMID: 35662229 PMCID: PMC9165397 DOI: 10.4103/1673-5374.339494] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Previous studies showed that acetyl-11-keto-beta-boswellic acid (AKBA), the active ingredient in the natural Chinese medicine Boswellia, can stimulate sciatic nerve injury repair via promoting Schwann cell proliferation. However, the underlying molecular mechanism remains poorly understood. In this study, we performed genomic sequencing in a rat model of sciatic nerve crush injury after gastric AKBA administration for 30 days. We found that the phagosome pathway was related to AKBA treatment, and brain-derived neurotrophic factor expression in the neurotrophic factor signaling pathway was also highly up-regulated. We further investigated gene and protein expression changes in the phagosome pathway and neurotrophic factor signaling pathway. Myeloperoxidase expression in the phagosome pathway was markedly decreased, and brain-derived neurotrophic factor, nerve growth factor, and nerve growth factor receptor expression levels in the neurotrophic factor signaling pathway were greatly increased. Additionally, expression levels of the inflammatory factors CD68, interleukin-1β, pro-interleukin-1β, and tumor necrosis factor-α were also decreased. Myelin basic protein- and β3-tubulin-positive expression as well as the axon diameter-to-total nerve diameter ratio in the injured sciatic nerve were also increased. These findings suggest that, at the molecular level, AKBA can increase neurotrophic factor expression through inhibiting myeloperoxidase expression and reducing inflammatory reactions, which could promote myelin sheath and axon regeneration in the injured sciatic nerve.
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9
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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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10
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Cui B, Wei L, Zhu ZJ, Sun LY. Neurophysiological characteristics in argininemia: a case report. Transl Pediatr 2021; 10:1947-1951. [PMID: 34430444 PMCID: PMC8349968 DOI: 10.21037/tp-21-112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/27/2021] [Indexed: 11/06/2022] Open
Abstract
Argininemia is a rare inherited disorder characterized by progressive spastic paraplegia, leading by mutation of the ARG1 gene. Liver transplantation (LT) had been reported to prevent symptoms progression, while its pathophysiology is still unclear. A 13-year-old male patient with argininemia for progressive neurological impairment was admitted to our center. Plasma amino acid screening showed a high concentration of arginine, and gene sequencing showed heterozygous mutation of the ARG1 gene. Spastic Paraplegia Rating Scale (SPRS), motor evoked potentials (MEPs), somatosensory evoked potentials (SEPs), F-wave, electromyography, nerve conduction velocity (NCV), and brain MRI were used to evaluate the patient. Herein, we describe the clinical characteristics of this patient, attempting a correlation between clinical, neurophysiological, and neuroimaging data in argininemia. Pyramidal tract dysfunction of lower limbs affected him, while only MEPs showed abnormalities among all neurophysiological evaluations, and mild cerebellum atrophy was observed. He responded poorly to traditional treatment such as a protein restriction diet and sodium benzoate. The symptoms of speech disorder, irritability, and dyskinesia were gradually deteriorating, so living-donor LT (LDLT) was done to prevent the progression. The symptoms improved significantly six months after LT, and the spasticity severity score decreased 50%. The findings suggest that LDLT is effective to argininemia, and the phenotypical similarities to other disorders that affect the urea cycle (HHH syndrome and pyrroline-5-carboxylate synthetase deficiency) suggest a common mechanism may contribute to maintaining the integrity of the corticospinal tract.
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Affiliation(s)
- Bin Cui
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Lin Wei
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Zhi-Jun Zhu
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Li-Ying Sun
- Liver Transplantation Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Center for Pediatric Liver Transplantation, Capital Medical University, Beijing, China.,National Clinical Research Center for Digestive Diseases, Beijing, China.,Intensive Care Unit, Beijing Friendship Hospital, Capital Medical University, Beijing, China
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11
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Nitzahn M, Lipshutz GS. CPS1: Looking at an ancient enzyme in a modern light. Mol Genet Metab 2020; 131:289-298. [PMID: 33317798 PMCID: PMC7738762 DOI: 10.1016/j.ymgme.2020.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/06/2023]
Abstract
The mammalian urea cycle (UC) is responsible for siphoning catabolic waste nitrogen into urea for excretion. Disruptions of the functions of any of the enzymes or transporters lead to elevated ammonia and neurological injury. Carbamoyl phosphate synthetase 1 (CPS1) is the first and rate-limiting UC enzyme responsible for the direct incorporation of ammonia into UC intermediates. Symptoms in CPS1 deficiency are typically the most severe of all UC disorders, and current clinical management is insufficient to prevent the associated morbidities and high mortality. With recent advances in basic and translational studies of CPS1, appreciation for this enzyme's essential role in the UC has been broadened to include systemic metabolic regulation during homeostasis and disease. Here, we review recent advances in CPS1 biology and contextualize them around the role of CPS1 in health and disease.
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Affiliation(s)
- Matthew Nitzahn
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Gerald S Lipshutz
- Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Psychiatry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA; Semel Institute for Neuroscience, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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12
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Tabarki B, Hakami W, Alkhuraish N, Tlili-Graies K, Alfadhel M. Spinal Cord Involvement in Pediatric-Onset Metabolic Disorders With Mendelian and Mitochondrial Inheritance. Front Pediatr 2020; 8:599861. [PMID: 33520891 PMCID: PMC7841137 DOI: 10.3389/fped.2020.599861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/24/2020] [Indexed: 01/31/2023] Open
Abstract
Previous reviews have described the features of brain involvement in pediatric-onset metabolic disorders with Mendelian and mitochondrial inheritance, but only a few have focused on spinal cord abnormalities. An increasing number of metabolic disorders with Mendelian and mitochondrial inheritance in children with predominant spinal cord involvement has been recognized. Spinal cord involvement may be isolated or may occur more frequently with brain involvement. Timely diagnosis and occasional genetic counseling are needed for timely therapy. Therefore, clinicians must be aware of the clinical, laboratory, and radiographic features of these disorders. In this review, we describe pediatric-onset metabolic disorders with Mendelian and mitochondrial inheritance and predominant spinal cord involvement. Furthermore, we provide an overview of these conditions, including background information and examples that require rapid identification, focusing on treatable conditions; that would be catastrophic if they are not recognized.
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Affiliation(s)
- Brahim Tabarki
- Division of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Wejdan Hakami
- Division of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Nader Alkhuraish
- Division of Neuroradiology, Department of Radiology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Kalthoum Tlili-Graies
- Division of Neuroradiology, Department of Radiology, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Medical Genomics Research Department, King Abdullah International Medical Research Center, King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia.,Genetics and Precision Medicine Department, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, King Abdullah Specialist Children's Hospital, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
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