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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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Elsayed LEO, Mohammed IN, Hamed AAA, Elseed MA, Salih MAM, Yahia A, Abubaker R, Koko M, Abd Allah ASI, Elbashir MI, Ibrahim ME, Brice A, Ahmed AE, Stevanin G. Novel Homozygous Missense Mutation in the ARG1 Gene in a Large Sudanese Family. Front Neurol 2020; 11:569996. [PMID: 33193012 PMCID: PMC7658625 DOI: 10.3389/fneur.2020.569996] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/25/2020] [Indexed: 12/16/2022] Open
Abstract
Background: Arginases catalyze the last step in the urea cycle. Hyperargininemia, a rare autosomal-recessive disorder of the urea cycle, presents after the first year of age with regression of milestones and evolves gradually into progressive spastic quadriplegia and cognitive dysfunction. Genetic studies reported various mutations in the ARG1 gene that resulted in hyperargininemia due to a complete or partial loss of arginase activity. Case Presentation: Five patients from an extended highly consanguineous Sudanese family presented with regression of the acquired milestones, spastic quadriplegia, and mental retardation. The disease onset ranged from 1 to 3 years of age. Two patients had epileptic seizures and one patient had stereotypic clapping. Genetic testing using whole-exome sequencing, done for the patients and a healthy parent, confirmed the presence of a homozygous novel missense variant in the ARG1 gene [GRCh37 (NM_001244438.1): exon 4: g.131902487T>A, c.458T>A, p.(Val153Glu)]. The variant was predicted pathogenic by five algorithms and affected a highly conserved amino acid located in the protein domain ureohydrolase, arginase subgroup. Sanger sequencing of 13 sampled family members revealed complete co-segregation between the variant and the disease distribution in the family in line with an autosomal-recessive mode of inheritance. Biochemical analysis confirmed hyperargininemia in five patients. Conclusion: This study reports the first Sudanese family with ARG1 mutation. The reported variant is a loss-of-function missense mutation. Its pathogenicity is strongly supported by the clinical phenotype, the computational functional impact prediction, the complete co-segregation with the disease, and the biochemical assessment.
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Affiliation(s)
- Liena E O Elsayed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan.,College of Medicine, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia.,Institut du Cerveau, INSERM, CNRS, Sorbonne Université, Paris, France
| | | | - Ahlam A A Hamed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Maha A Elseed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Mustafa A M Salih
- Division of Pediatric Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Ashraf Yahia
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan.,Institut du Cerveau, INSERM, CNRS, Sorbonne Université, Paris, France.,Department of Biochemistry, Faculty of Medicine, National University, Khartoum, Sudan.,Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France
| | - Rayan Abubaker
- Department of Molecular Biology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Mahmoud Koko
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, Tuebingen, Germany
| | | | | | - Muntaser E Ibrahim
- Department of Molecular Biology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Alexis Brice
- Institut du Cerveau, INSERM, CNRS, Sorbonne Université, Paris, France.,APHP, Pitié-Salpêtrière Hospital, Department of genetics, Paris, France
| | - Ammar E Ahmed
- Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Giovanni Stevanin
- Institut du Cerveau, INSERM, CNRS, Sorbonne Université, Paris, France.,Ecole Pratique des Hautes Etudes, EPHE, PSL Research University, Paris, France.,APHP, Pitié-Salpêtrière Hospital, Department of genetics, Paris, France
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