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Posset R, Garbade SF, Gleich F, Scharre S, Okun JG, Gropman AL, Nagamani SCS, Druck AC, Epp F, Hoffmann GF, Kölker S, Zielonka M. Severity-adjusted evaluation of liver transplantation on health outcomes in urea cycle disorders. Genet Med 2024; 26:101039. [PMID: 38054409 DOI: 10.1016/j.gim.2023.101039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/07/2023] Open
Abstract
PURPOSE Liver transplantation (LTx) is performed in individuals with urea cycle disorders when medical management (MM) insufficiently prevents the occurrence of hyperammonemic events. However, there is a paucity of systematic analyses on the effects of LTx on health-related outcome parameters compared to individuals with comparable severity who are medically managed. METHODS We investigated the effects of LTx and MM on validated health-related outcome parameters, including the metabolic disease course, linear growth, and neurocognitive outcomes. Individuals were stratified into "severe" and "attenuated" categories based on the genotype-specific and validated in vitro enzyme activity. RESULTS LTx enabled metabolic stability by prevention of further hyperammonemic events after transplantation and was associated with a more favorable growth outcome compared with individuals remaining under MM. However, neurocognitive outcome in individuals with LTx did not differ from the medically managed counterparts as reflected by the frequency of motor abnormality and cognitive standard deviation score at last observation. CONCLUSION Whereas LTx enabled metabolic stability without further need of protein restriction or nitrogen-scavenging therapy and was associated with a more favorable growth outcome, LTx-as currently performed-was not associated with improved neurocognitive outcomes compared with long-term MM in the investigated urea cycle disorders.
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Affiliation(s)
- Roland Posset
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany.
| | - Sven F Garbade
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Florian Gleich
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Svenja Scharre
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G Okun
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Andrea L Gropman
- Children's National Health System and The George Washington School of Medicine, Washington, DC
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX
| | - Ann-Catrin Druck
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Friederike Epp
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Matthias Zielonka
- Heidelberg University, Medical Faculty Heidelberg, and Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany.
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Seidl MJ, Scharre S, Posset R, Druck AC, Epp F, Okun JG, Dimitrov B, Hoffmann GF, Kölker S, Zielonka M. ASS1 deficiency is associated with impaired neuronal differentiation in zebrafish larvae. Mol Genet Metab 2024; 141:108097. [PMID: 38113552 DOI: 10.1016/j.ymgme.2023.108097] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 11/22/2023] [Accepted: 11/23/2023] [Indexed: 12/21/2023]
Abstract
Citrullinemia type 1 (CTLN1) is a rare autosomal recessive urea cycle disorder caused by deficiency of the cytosolic enzyme argininosuccinate synthetase 1 (ASS1) due to pathogenic variants in the ASS1 gene located on chromosome 9q34.11. Even though hyperammenomia is considered the major pathomechanistic factor for neurological impairment and cognitive dysfunction, a relevant subset of individuals presents with a neurodegenerative course in the absence of hyperammonemic decompensations. Here we show, that ASS1 deficiency induced by antisense-mediated knockdown of the zebrafish ASS1 homologue is associated with defective neuronal differentiation ultimately causing neuronal cell loss and consecutively decreased brain size in zebrafish larvae in vivo. Whereas ASS1-deficient zebrafish larvae are characterized by markedly elevated concentrations of citrulline - the biochemical hallmark of CTLN1, accumulation of L-citrulline, hyperammonemia or therewith associated secondary metabolic alterations did not account for the observed phenotype. Intriguingly, coinjection of the human ASS1 mRNA not only normalized citrulline concentration but also reversed the morphological cerebral phenotype and restored brain size, confirming conserved functional properties of ASS1 across species. The results of the present study imply a novel, potentially non-enzymatic (moonlighting) function of the ASS1 protein in neurodevelopment.
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Affiliation(s)
- Marie J Seidl
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Svenja Scharre
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Roland Posset
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Ann-Catrin Druck
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Friederike Epp
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G Okun
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Bianca Dimitrov
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Georg F Hoffmann
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Matthias Zielonka
- Heidelberg University, Medical Faculty Heidelberg, and Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Heidelberg, Germany.
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Scharre S, Posset R, Garbade SF, Gleich F, Seidl MJ, Druck AC, Okun JG, Gropman AL, Nagamani SCS, Hoffmann GF, Kölker S, Zielonka M. Predicting the disease severity in male individuals with ornithine transcarbamylase deficiency. Ann Clin Transl Neurol 2022; 9:1715-1726. [PMID: 36217298 PMCID: PMC9639638 DOI: 10.1002/acn3.51668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 09/01/2022] [Accepted: 09/06/2022] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVE Ornithine transcarbamylase deficiency (OTC-D) is an X-linked metabolic disease and the most common urea cycle disorder. Due to high phenotypic heterogeneity, ranging from lethal neonatal hyperammonemic events to moderate symptoms and even asymptomatic individuals, the prediction of the disease course at an early disease stage is very important to individually adjust therapies such as medical treatment or liver transplantation. In this translational study, we developed a severity-adjusted classification system based on in vitro residual enzymatic OTC activity. METHODS Applying a cell-based expression system, residual enzymatic OTC activities of 71 pathogenic OTC variants were spectrophotometrically determined and subsequently correlated with clinical and biochemical outcome parameters of 119 male individuals with OTC-D (mOTC-D) as reported in the UCDC and E-IMD registries. RESULTS Integration of multiple data sources enabled the establishment of a robust disease prediction model for mOTC-D. Residual enzymatic OTC activity not only correlates with age at first symptoms, initial peak plasma ammonium concentration and frequency of metabolic decompensations but also predicts mortality. The critical threshold of 4.3% residual enzymatic activity distinguishes a severe from an attenuated phenotype. INTERPRETATION Residual enzymatic OTC activity reliably predicts the disease severity in mOTC-D and could thus serve as a tool for severity-adjusted evaluation of therapeutic strategies and counselling patients and parents.
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Affiliation(s)
- Svenja Scharre
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Roland Posset
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Sven F Garbade
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Florian Gleich
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Marie J Seidl
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Ann-Catrin Druck
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jürgen G Okun
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Andrea L Gropman
- Division of Neurodevelopmental Pediatrics and Neurogenetics, Children's National Health System and The George Washington School of Medicine, Washington, District of Columbia, USA
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Georg F Hoffmann
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Matthias Zielonka
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany.,Heidelberg Research Center for Molecular Medicine (HRCMM), Heidelberg, Germany
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Posset R, Kölker S, Gleich F, Okun JG, Gropman AL, Nagamani SCS, Scharre S, Probst J, Walter ME, Hoffmann GF, Garbade SF, Zielonka M. Severity-adjusted evaluation of newborn screening on the metabolic disease course in individuals with cytosolic urea cycle disorders. Mol Genet Metab 2020; 131:390-397. [PMID: 33288448 PMCID: PMC8315358 DOI: 10.1016/j.ymgme.2020.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVE The implementation of newborn screening (NBS) programs for citrullinemia type 1 (CTLN1) and argininosuccinic aciduria (ASA) is subject to controversial debate. The aim of this study was to assess the impact of NBS on the metabolic disease course and clinical outcome of affected individuals. METHODS In 115 individuals with CTLN1 and ASA, we compared the severity of the initial hyperammonemic episode (HAE) and the frequency of (subsequent) HAEs with the mode of diagnosis. Based on a recently established functional disease prediction model, individuals were stratified according to their predicted severe or attenuated phenotype. RESULTS Individuals with predicted attenuated forms of CTLN1 and ASA were overrepresented in the NBS group, while those with a predicted severe phenotype were underrepresented compared to individuals identified after the manifestation of symptoms (SX). Identification by NBS was associated with reduced severity of the initial HAE both in individuals with predicted severe and attenuated phenotypes, while it was not associated with lower frequency of (subsequent) HAEs. Similar results were obtained when including some patients diagnosed presymptomatically (i.e. prenatal testing, and high-risk family screening) in this analysis. CONCLUSION Since one of the major challenges of NBS outcome studies is the potential overrepresentation of individuals with predicted attenuated phenotypes in NBS cohorts, severity-adjusted evaluation of screened and unscreened individuals is important to avoid overestimation of the NBS effect. NBS enables the attenuation of the initial HAE but does not affect the frequency of subsequent metabolic decompensations in individuals with CTLN1 and ASA. Future long-term studies will need to evaluate the clinical impact of this finding, especially with regard to mortality, as well as cognitive outcome and quality of life of survivors.
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Affiliation(s)
- Roland Posset
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Stefan Kölker
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Florian Gleich
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Jürgen G Okun
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Andrea L Gropman
- Children's National Health System and The George Washington School of Medicine, Washington, DC, USA
| | - Sandesh C S Nagamani
- Department of Molecular and Human Genetics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA
| | - Svenja Scharre
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Joris Probst
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Magdalena E Walter
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Georg F Hoffmann
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Sven F Garbade
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany
| | - Matthias Zielonka
- Center for Pediatric and Adolescent Medicine, Division of Pediatric Neurology and Metabolic Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 430, 69120 Heidelberg, Germany; Heidelberg Research Center for Molecular Medicine (HRCMM), Heidelberg, Germany.
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