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Naguib S, Mansour LA, Soliman NA, El-Hanafy HM, Fahmy YA, Elmonem MA, Halim RMA. Expanding the Genetic Spectrum of AGXT Gene Variants in Egyptian Patients with Primary Hyperoxaluria Type I. Genet Test Mol Biomarkers 2024; 28:151-158. [PMID: 38657121 DOI: 10.1089/gtmb.2023.0525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
Introduction: Approximately 80% of primary hyperoxaluria cases are caused by primary hyperoxaluria type 1 (PH1, OMIM# 259900), which is characterized by pathogenic variants in the AGXT gene, resulting in deficiency of the liver-specific enzyme alanine-glyoxylate aminotransferase (AGT). This leads to increased production of oxalate, which cannot be effectively eliminated from the body, resulting in its accumulation primarily in the kidneys and other organs. Subjects and Methods: This study included 17 PH1 Egyptian patients from 12 unrelated families, recruited from the Inherited Kidney Disease Outpatient Clinic and the Dialysis Units, Cairo University Hospitals, during the period from January 2018 to December 2019, aiming to identify the pathogenic variants in the AGXT gene. Results: Six different variants were detected. These included three frameshift and three missense variants, all found in homozygosity within the respective families. The most common variant was c.121G>A;p.(Gly41Arg) detected in four families, followed by c.725dup;p.(Asp243GlyfsTer12) in three families, c.33dup;p.(Lys12Glnfs156) in two families, and c.731T >C;p.(Ile244Thr), c.33delC;p.(Lys12Argfs34), and c.568G>A;p.(Gly190Arg) detected in one family each. Conclusion: Consanguineous Egyptian families with history of renal stones or renal disease suspicious of primary hyperoxaluria should undergo AGXT genetic sequencing, specifically targeting exons 1 and 7, as variants in these two exons account for >75% of disease-causing variants in Egyptian patients with confirmed PH1.
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Affiliation(s)
- Somayya Naguib
- Department of Clinical and Chemical Pathology, Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Lamiaa A Mansour
- Department of Clinical and Chemical Pathology, Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Neveen A Soliman
- Department of Pediatrics, Center of Pediatric Nephrology and Transplantation (CPNT), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
- Egyptian Group for Orphan Renal Disease (EGORD), Cairo, Egypt
- Department of Clinical Genetics, Egypt Center for Research and Regenerative Medicine (ECRRM), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Hadeel M El-Hanafy
- Department of Clinical and Chemical Pathology, Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Yosra A Fahmy
- Department of Pediatrics, Center of Pediatric Nephrology and Transplantation (CPNT), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
- Egyptian Group for Orphan Renal Disease (EGORD), Cairo, Egypt
| | - Mohamed A Elmonem
- Department of Clinical and Chemical Pathology, Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
- Department of Clinical Genetics, Egypt Center for Research and Regenerative Medicine (ECRRM), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Radwa M Abdel Halim
- Department of Clinical and Chemical Pathology, Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
- Department of Clinical and Chemical Pathology, Faculty of Medicine, New Giza University, Giza, Egypt
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Meyer M, Hollenbeck JC, Reunert J, Seelhöfer A, Rust S, Fobker M, Biskup S, Och U, Linden M, Sass JO, Marquardt T. 3-Hydroxyisobutyrate dehydrogenase (HIBADH) deficiency-A novel disorder of valine metabolism. J Inherit Metab Dis 2021; 44:1323-1329. [PMID: 34176136 DOI: 10.1002/jimd.12410] [Citation(s) in RCA: 3] [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: 10/30/2020] [Revised: 06/04/2021] [Accepted: 06/14/2021] [Indexed: 11/08/2022]
Abstract
3-Hydroxyisobutyric acid (3HiB) is an intermediate in the degradation of the branched-chain amino acid valine. Disorders in valine degradation can lead to 3HiB accumulation and its excretion in the urine. This article describes the first two patients with a new metabolic disorder, 3-hydroxyisobutyrate dehydrogenase (HIBADH) deficiency, its phenotype and its treatment with a low-valine diet. The detected mutation in the HIBADH gene leads to nonsense-mediated mRNA decay of the mutant allele and to a complete loss-of-function of the enzyme. Under strict adherence to a low-valine diet a rapid decrease of 3HiB excretion in the urine was observed. Due to limited patient numbers and intrafamilial differences in phenotype with one affected and one unaffected individual, the clinical phenotype of HIBADH deficiency needs further evaluation.
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Affiliation(s)
- Melanie Meyer
- Department of General Pediatrics, University Hospital, Münster, Germany
| | - Jana C Hollenbeck
- Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences & Institute for Functional Gene Analytics (IFGA), RG Inborn Errors of Metabolism, Rheinbach, Germany
| | - Janine Reunert
- Department of General Pediatrics, University Hospital, Münster, Germany
| | - Anja Seelhöfer
- Department of General Pediatrics, University Hospital, Münster, Germany
| | - Stephan Rust
- Department of General Pediatrics, University Hospital, Münster, Germany
| | - Manfred Fobker
- Center for Laboratory Medicine, University Hospital, Münster, Germany
| | - Saskia Biskup
- CeGaT GmbH und Praxis für Humangenetik Tübingen, Tübingen, Germany
| | - Ulrike Och
- Department of General Pediatrics, University Hospital, Münster, Germany
| | | | - Jörn Oliver Sass
- Bonn-Rhein-Sieg University of Applied Sciences, Department of Natural Sciences & Institute for Functional Gene Analytics (IFGA), RG Inborn Errors of Metabolism, Rheinbach, Germany
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