1
|
Khalil Y, Footitt E, Vootukuri R, Wempe MF, Coughlin CR, Batzios S, Wilson MP, Kožich V, Clayton PT, Mills PB. Assessment of urinary 6-oxo-pipecolic acid as a biomarker for ALDH7A1 deficiency. J Inherit Metab Dis 2024. [PMID: 39038845 DOI: 10.1002/jimd.12783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/20/2024] [Accepted: 07/08/2024] [Indexed: 07/24/2024]
Abstract
ALDH7A1 deficiency is an epileptic encephalopathy whose seizures respond to treatment with supraphysiological doses of pyridoxine. It arises as a result of damaging variants in ALDH7A1, a gene in the lysine catabolism pathway. α-Aminoadipic semialdehyde (α-AASA) and Δ1-piperideine-6-carboxylate (P6C), which accumulate because of the block in the lysine pathway, are diagnostic biomarkers for this disorder. Recently, it has been reported that 6-oxo-pipecolic acid (6-oxo-PIP) also accumulates in the urine, CSF and plasma of ALDH7A1-deficient individuals and that, given its improved stability, it may be a more suitable biomarker for this disorder. This study measured 6-oxo-PIP in urine from a cohort of 30 patients where α-AASA was elevated and showed that it was above the normal range in all those above 6 months of age. However, 6-oxo-PIP levels were within the normal range in 33% of the patients below 6 months of age. Levels increased with age and correlated with a decrease in α-AASA levels. Longitudinal analysis of urine samples from ALDH7A1-deficient patients who were on a lysine restricted diet whilst receiving supraphysiological doses of pyridoxine showed that levels of 6-oxo-PIP remained elevated whilst α-AASA decreased. Similar to α-AASA, we found that elevated urinary excretion of 6-oxo-PIP can also occur in individuals with molybdenum cofactor deficiency. This study demonstrates that urinary 6-oxo-PIP may not be a suitable biomarker for ALDH7A1 deficiency in neonates. However, further studies are needed to understand the biochemistry leading to its accumulation and its potential long-term side effects.
Collapse
Affiliation(s)
- Youssef Khalil
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
| | - Emma Footitt
- Department of Metabolic Paediatrics, Great Ormond Street Hospital, London, UK
| | - Reddy Vootukuri
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
| | - Michael F Wempe
- School of Pharmacy, Department of Pharmaceutical Sciences, University of Colorado, Aurora, Colorado, USA
| | - Curtis R Coughlin
- Department of Pediatrics, Section of Clinical Genetics and Metabolism, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Spyros Batzios
- Department of Metabolic Paediatrics, Great Ormond Street Hospital, London, UK
| | - Matthew P Wilson
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
- Laboratory for Molecular Diagnosis, Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Viktor Kožich
- Department of Pediatrics and Inherited Metabolic Disorders, Charles University-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Peter T Clayton
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
| | - Philippa B Mills
- Genetics and Genomic Medicine, University College London Great Ormond Street Institute of Child Health, London, UK
| |
Collapse
|
2
|
Ohl L, Kuhs A, Pluck R, Durham E, Noji M, Philip ND, Arany Z, Ahrens-Nicklas RC. Partial suppression of BCAA catabolism as a potential therapy for BCKDK deficiency. Mol Genet Metab Rep 2024; 39:101091. [PMID: 38770403 PMCID: PMC11103483 DOI: 10.1016/j.ymgmr.2024.101091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 05/04/2024] [Accepted: 05/06/2024] [Indexed: 05/22/2024] Open
Abstract
Branched chain ketoacid dehydrogenase kinase (BCKDK) deficiency is a recently described inherited neurometabolic disorder of branched chain amino acid (BCAA) metabolism implying increased BCAA catabolism. It has been hypothesized that a severe reduction in systemic BCAA levels underlies the disease pathophysiology, and that BCAA supplementation may ameliorate disease phenotypes. To test this hypothesis, we characterized a recent mouse model of BCKDK deficiency and evaluated the efficacy of enteral BCAA supplementation in this model. Surprisingly, BCAA supplementation exacerbated neurodevelopmental deficits and did not correct biochemical abnormalities despite increasing systemic BCAA levels. These data suggest that aberrant flux through the BCAA catabolic pathway, not just BCAA insufficiency, may contribute to disease pathology. In support of this conclusion, genetic re-regulation of BCAA catabolism, through Dbt haploinsufficiency, partially rescued biochemical and behavioral phenotypes in BCKDK deficient mice. Collectively, these data raise into question assumptions widely made about the pathophysiology of BCKDK insufficiency and suggest a novel approach to develop potential therapies for this disease.
Collapse
Affiliation(s)
- Laura Ohl
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- College of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amanda Kuhs
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ryan Pluck
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emily Durham
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Michael Noji
- College of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nathan D. Philip
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Zoltan Arany
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rebecca C. Ahrens-Nicklas
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
3
|
Thöny B, Ng J, Kurian MA, Mills P, Martinez A. Mouse models for inherited monoamine neurotransmitter disorders. J Inherit Metab Dis 2024; 47:533-550. [PMID: 38168036 DOI: 10.1002/jimd.12710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/07/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
Several mouse models have been developed to study human defects of primary and secondary inherited monoamine neurotransmitter disorders (iMND). As the field continues to expand, current defects in corresponding mouse models include enzymes and a molecular co-chaperone involved in monoamine synthesis and metabolism (PAH, TH, PITX3, AADC, DBH, MAOA, DNAJC6), tetrahydrobiopterin (BH4) cofactor synthesis and recycling (adGTPCH1/DRD, arGTPCH1, PTPS, SR, DHPR), and vitamin B6 cofactor deficiency (ALDH7A1), as well as defective monoamine neurotransmitter packaging (VMAT1, VMAT2) and reuptake (DAT). No mouse models are available for human DNAJC12 co-chaperone and PNPO-B6 deficiencies, disorders associated with recessive variants that result in decreased stability and function of the aromatic amino acid hydroxylases and decreased neurotransmitter synthesis, respectively. More than one mutant mouse is available for some of these defects, which is invaluable as different variant-specific (knock-in) models may provide more insights into underlying mechanisms of disorders, while complete gene inactivation (knock-out) models often have limitations in terms of recapitulating complex human diseases. While these mouse models have common phenotypic traits also observed in patients, reflecting the defective homeostasis of the monoamine neurotransmitter pathways, they also present with disease-specific manifestations with toxic accumulation or deficiency of specific metabolites related to the specific gene affected. This review provides an overview of the currently available models and may give directions toward selecting existing models or generating new ones to investigate novel pathogenic mechanisms and precision therapies.
Collapse
Affiliation(s)
- Beat Thöny
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zürich, Switzerland
| | - Joanne Ng
- Genetic Therapy Accelerator Centre, University College London, Queen Square Institute of Neurology, London, UK
| | - Manju A Kurian
- Zayed Centre for Research into Rare Disease in Children, GOS Institute of Child Health, University College London, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Philippa Mills
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Aurora Martinez
- Department of Biomedicine and Center for Translational Research in Parkinson's Disease, University of Bergen, Bergen, Norway
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
| |
Collapse
|
4
|
Yan J, Wu J, Xu M, Wang M, Guo W. Disrupted de novo pyrimidine biosynthesis impairs adult hippocampal neurogenesis and cognition in pyridoxine-dependent epilepsy. SCIENCE ADVANCES 2024; 10:eadl2764. [PMID: 38579001 PMCID: PMC10997211 DOI: 10.1126/sciadv.adl2764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/04/2024] [Indexed: 04/07/2024]
Abstract
Despite seizure control by early high-dose pyridoxine (vitamin B6) treatment, at least 75% of pyridoxine-dependent epilepsy (PDE) patients with ALDH7A1 mutation still suffer from intellectual disability. It points to a need for additional therapeutic interventions for PDE beyond pyridoxine treatment, which provokes us to investigate the mechanisms underlying the impairment of brain hemostasis by ALDH7A1 deficiency. In this study, we show that ALDH7A1-deficient mice with seizure control exhibit altered adult hippocampal neurogenesis and impaired cognitive functions. Mechanistically, ALDH7A1 deficiency leads to the accumulation of toxic lysine catabolism intermediates, α-aminoadipic-δ-semialdehyde and its cyclic form, δ-1-piperideine-6-carboxylate, which in turn impair de novo pyrimidine biosynthesis and inhibit NSC proliferation and differentiation. Notably, supplementation of pyrimidines rescues abnormal neurogenesis and cognitive impairment in ALDH7A1-deficient adult mice. Therefore, our findings not only define the important role of ALDH7A1 in the regulation of adult hippocampal neurogenesis but also provide a potential therapeutic intervention to ameliorate the defective mental capacities in PDE patients with seizure control.
Collapse
Affiliation(s)
- Jianfei Yan
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100093, China
| | - Junjie Wu
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100093, China
| | - Mingyue Xu
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100093, China
| | - Min Wang
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Weixiang Guo
- State Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100093, China
| |
Collapse
|
5
|
Ohl L, Kuhs A, Pluck R, Durham E, Noji M, Philip ND, Arany Z, Ahrens-Nicklas RC. Partial suppression of BCAA catabolism as a potential therapy for BCKDK deficiency. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.12.560929. [PMID: 37873402 PMCID: PMC10592755 DOI: 10.1101/2023.10.12.560929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Branched chain ketoacid dehydrogenase kinase (BCKDK) deficiency is a recently described inherited neurometabolic disorder of branched chain amino acid (BCAA) metabolism implying increased BCAA catabolism. It has been hypothesized that a severe reduction in systemic BCAA levels underlies the disease pathophysiology, and that BCAA supplementation may ameliorate disease phenotypes. To test this hypothesis, we characterized a recent mouse model of BCKDK deficiency and evaluated the efficacy of enteral BCAA supplementation in this model. Surprisingly, BCAA supplementation exacerbated neurodevelopmental deficits and did not correct biochemical abnormalities despite increasing systemic BCAA levels. These data suggest that aberrant flux through the BCAA catabolic pathway, not just BCAA insufficiency, may contribute to disease pathology. In support of this conclusion, genetic re-regulation of BCAA catabolism, through Dbt haploinsufficiency, partially rescued biochemical and behavioral phenotypes in BCKDK deficient mice. Collectively, these data raise into question assumptions widely made about the pathophysiology of BCKDK insufficiency and suggest a novel approach to develop potential therapies for this disease.
Collapse
|
6
|
Plecko B. On pathways and blind alleys-The importance of biomarkers in vitamin B 6 -dependent epilepsies. J Inherit Metab Dis 2023; 46:839-847. [PMID: 37428623 DOI: 10.1002/jimd.12655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
Over the past two decades, the field of vitamin B6 -dependent epilepsies has evolved by the recognition of a growing number of gene defects (ALDH7A1, PNPO, ALPL, ALDH4A1, PLPBP as well as defects of the glycosylphosphatidylinositol anchor proteins) that all lead to reduced availability of pyridoxal 5'-phosphate, an important cofactor in neurotransmitter and amino acid metabolism. In addition, positive pyridoxine response has been observed in other monogenic defects such as MOCS2 deficiency or KCNQ2 and there may be more defects to be discovered. Most entities lead to neonatal onset pharmaco-resistant myoclonic seizures or even status epilepticus and pose an emergency to the treating physician. Research has unraveled specific biomarkers for several of these entities (PNPO deficiency, ALDH7A1 deficiency, ALDH4A1 deficiency, ALPL deficiency causing congenital hypophosphatasia and glycosylphosphatidylinositol anchoring defects with hyperphosphatasia), that can be detected in plasma or urine, while there is no biomarker to test for PLPHP deficiency. Secondary elevation of glycine or lactate was recognized as diagnostic pitfall. An algorithm for a standardized trial with vitamin B6 should be in place in every newborn unit in order not to miss these well-treatable inborn errors of metabolism. The Komrower lecture of 2022 provided me with the opportunity to tell the story about the conundrums of research into vitamin B6 -dependent epilepsies that kept some surprises and many novel insights into pathomechanisms of vitamin metabolism. Every single step had benefits for the patients and families that we care for and advocates for a close collaboration of clinician scientists with basic research.
Collapse
Affiliation(s)
- Barbara Plecko
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| |
Collapse
|
7
|
Sun S, Wang H. Clocking Epilepsies: A Chronomodulated Strategy-Based Therapy for Rhythmic Seizures. Int J Mol Sci 2023; 24:ijms24044223. [PMID: 36835631 PMCID: PMC9962262 DOI: 10.3390/ijms24044223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/08/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Epilepsy is a neurological disorder characterized by hypersynchronous recurrent neuronal activities and seizures, as well as loss of muscular control and sometimes awareness. Clinically, seizures have been reported to display daily variations. Conversely, circadian misalignment and circadian clock gene variants contribute to epileptic pathogenesis. Elucidation of the genetic bases of epilepsy is of great importance because the genetic variability of the patients affects the efficacies of antiepileptic drugs (AEDs). For this narrative review, we compiled 661 epilepsy-related genes from the PHGKB and OMIM databases and classified them into 3 groups: driver genes, passenger genes, and undetermined genes. We discuss the potential roles of some epilepsy driver genes based on GO and KEGG analyses, the circadian rhythmicity of human and animal epilepsies, and the mutual effects between epilepsy and sleep. We review the advantages and challenges of rodents and zebrafish as animal models for epileptic studies. Finally, we posit chronomodulated strategy-based chronotherapy for rhythmic epilepsies, integrating several lines of investigation for unraveling circadian mechanisms underpinning epileptogenesis, chronopharmacokinetic and chronopharmacodynamic examinations of AEDs, as well as mathematical/computational modeling to help develop time-of-day-specific AED dosing schedules for rhythmic epilepsy patients.
Collapse
Affiliation(s)
- Sha Sun
- Center for Circadian Clocks, Soochow University, Suzhou 215123, China
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou 215123, China
| | - Han Wang
- Center for Circadian Clocks, Soochow University, Suzhou 215123, China
- School of Biology and Basic Medical Sciences, Suzhou Medical College, Soochow University, Suzhou 215123, China
- Correspondence: or ; Tel.: +86-186-0512-8971
| |
Collapse
|
8
|
Crowther LM, Poms M, Zandl-Lang M, Abela L, Hartmann H, Seiler M, Mathis D, Plecko B. Metabolomics analysis of antiquitin deficiency in cultured human cells and plasma: Relevance to pyridoxine-dependent epilepsy. J Inherit Metab Dis 2023; 46:129-142. [PMID: 36225138 PMCID: PMC10092344 DOI: 10.1002/jimd.12569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 10/09/2022] [Accepted: 10/10/2022] [Indexed: 01/19/2023]
Abstract
Deficiency of antiquitin (α-aminoadipic semialdehyde dehydrogenase), an enzyme involved in lysine degradation and encoded by ALDH7A1, is the major cause of vitamin B6 -dependent epilepsy (PDE-ALDH7A1). Despite seizure control with high dose pyridoxine (PN), developmental delay still occurs in approximately 70% of patients. We aimed to investigate metabolic perturbations due to possible previously unidentified roles of antiquitin, which may contribute to developmental delay, as well as metabolic effects of high dose pyridoxine supplementation reflecting the high doses used for seizure control in patients with PDE-ALDH7A1. Untargeted metabolomics by high resolution mass spectrometry (HRMS) was used to analyze plasma of patients with PDE-ALDH7A1 and two independently generated lines of cultured ReNcell CX human neuronal progenitor cells (NPCs) with CRISPR/Cas mediated antiquitin deficiency. Accumulation of lysine pathway metabolites in antiquitin-deficient NPCs and western-blot analysis confirmed knockdown of ALDH7A1. Metabolomics analysis of antiquitin-deficient NPCs in conditions of lysine restriction and PN supplementation identified changes in metabolites related to the transmethylation and transsulfuration pathways and osmolytes, indicating a possible unrecognized role of antiquitin outside the lysine degradation pathway. Analysis of plasma samples of PN treated patients with PDE-ALDH7A1 and antiquitin-deficient NPCs cultured in conditions comparable to the patient plasma samples demonstrated perturbation of metabolites of the gamma-glutamyl cycle, suggesting potential oxidative stress-related effects in PN-treated patients with PDE-ALDH7A1. We postulate that a model of human NPCs with CRISPR/Cas mediated antiquitin deficiency is well suited to characterize previously unreported roles of antiquitin, relevant to this most prevalent form of pyridoxine-dependent epilepsy.
Collapse
Affiliation(s)
- Lisa M Crowther
- Division of Child Neurology, University Children's Hospital Zurich, Zurich, Switzerland
- CRC Clinical Research Center, University Children's Hospital Zurich, Zurich, Switzerland
- Radiz-Rare Disease Intiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
| | - Martin Poms
- Division of Child Neurology, University Children's Hospital Zurich, Zurich, Switzerland
- CRC Clinical Research Center, University Children's Hospital Zurich, Zurich, Switzerland
- Radiz-Rare Disease Intiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Department of Clinical Chemistry and Biochemistry, University Children's Hospital Zurich, Zurich, Switzerland
| | - Martina Zandl-Lang
- Department of Pediatrics and Adolescent Medicine, Division of General Pediatrics, Medical University of Graz, Graz, Austria
| | - Lucia Abela
- Division of Child Neurology, University Children's Hospital Zurich, Zurich, Switzerland
- Molecular Neurosciences, Developmental Neuroscience, UCL Institute of Child Health, London, UK
| | - Hans Hartmann
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Michelle Seiler
- Pediatric Emergency Department, University Children's Hospital Zurich, Zurich, Switzerland
| | - Déborah Mathis
- Department of Clinical Chemistry and Biochemistry, University Children's Hospital Zurich, Zurich, Switzerland
- University Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Barbara Plecko
- Division of Child Neurology, University Children's Hospital Zurich, Zurich, Switzerland
- CRC Clinical Research Center, University Children's Hospital Zurich, Zurich, Switzerland
- Radiz-Rare Disease Intiative Zurich, Clinical Research Priority Program for Rare Diseases, University of Zurich, Zurich, Switzerland
- Department of Pediatrics and Adolescent Medicine, Division of General Pediatrics, Medical University of Graz, Graz, Austria
| |
Collapse
|
9
|
Global Metabolomics Discovers Two Novel Biomarkers in Pyridoxine-Dependent Epilepsy Caused by ALDH7A1 Deficiency. Int J Mol Sci 2022; 23:ijms232416061. [PMID: 36555701 PMCID: PMC9784804 DOI: 10.3390/ijms232416061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive developmental and epileptic encephalopathy caused by pathogenic variants in the ALDH7A1 gene (PDE-ALDH7A1), which mainly has its onset in neonates and infants. Early diagnosis and treatment are crucial to prevent severe neurological sequelae or death. Sensitive, specific, and stable biomarkers for diagnostic evaluations and follow-up examinations are essential to optimize outcomes. However, most of the known biomarkers for PDE lack these criteria. Additionally, there is little discussion regarding the interdependence of biomarkers in the PDE-ALDH7A1 metabolite profile. Therefore, the aim of this study was to understand the underlying mechanisms in PDE-ALDH7A1 and to discover new biomarkers in the plasma of patients using global metabolomics. Plasma samples from 9 patients with genetically confirmed PDE-ALDH7A1 and 22 carefully selected control individuals were analyzed by ultra high performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). Two novel and reliable pyridoxine-independent diagnostic markers, 6-hydroxy-2-aminocaproic acid (HACA) and an isomer of C9H11NO4, were identified. Furthermore, a possible reaction mechanism is proposed for HACA. This study demonstrates the capability of global metabolomics in disease screening to detect established and novel biomarkers.
Collapse
|
10
|
Goodspeed K, Bailey RM, Prasad S, Sadhu C, Cardenas JA, Holmay M, Bilder DA, Minassian BA. Gene Therapy: Novel Approaches to Targeting Monogenic Epilepsies. Front Neurol 2022; 13:805007. [PMID: 35847198 PMCID: PMC9284605 DOI: 10.3389/fneur.2022.805007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 04/20/2022] [Indexed: 11/18/2022] Open
Abstract
Genetic epilepsies are a spectrum of disorders characterized by spontaneous and recurrent seizures that can arise from an array of inherited or de novo genetic variants and disrupt normal brain development or neuronal connectivity and function. Genetically determined epilepsies, many of which are due to monogenic pathogenic variants, can result in early mortality and may present in isolation or be accompanied by neurodevelopmental disability. Despite the availability of more than 20 antiseizure medications, many patients with epilepsy fail to achieve seizure control with current therapies. Patients with refractory epilepsy—particularly of childhood onset—experience increased risk for severe disability and premature death. Further, available medications inadequately address the comorbid developmental disability. The advent of next-generation gene sequencing has uncovered genetic etiologies and revolutionized diagnostic practices for many epilepsies. Advances in the field of gene therapy also present the opportunity to address the underlying mechanism of monogenic epilepsies, many of which have only recently been described due to advances in precision medicine and biology. To bring precision medicine and genetic therapies closer to clinical applications, experimental animal models are needed that replicate human disease and reflect the complexities of these disorders. Additionally, identifying and characterizing clinical phenotypes, natural disease course, and meaningful outcome measures from epileptic and neurodevelopmental perspectives are necessary to evaluate therapies in clinical studies. Here, we discuss the range of genetically determined epilepsies, the existing challenges to effective clinical management, and the potential role gene therapy may play in transforming treatment options available for these conditions.
Collapse
Affiliation(s)
- Kimberly Goodspeed
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
| | - Rachel M. Bailey
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
- Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern, Dallas, TX, United States
| | - Suyash Prasad
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Chanchal Sadhu
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Jessica A. Cardenas
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Mary Holmay
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Deborah A. Bilder
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT, United States
| | - Berge A. Minassian
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
- *Correspondence: Berge A. Minassian
| |
Collapse
|
11
|
Engelke UF, van Outersterp RE, Merx J, van Geenen FA, van Rooij A, Berden G, Huigen MC, Kluijtmans LA, Peters TM, Al-Shekaili HH, Leavitt BR, de Vrieze E, Broekman S, van Wijk E, Tseng LA, Kulkarni P, Rutjes FP, Mecinović J, Struys EA, Jansen LA, Gospe SM, Mercimek-Andrews S, Hyland K, Willemsen MA, Bok LA, van Karnebeek CD, Wevers RA, Boltje TJ, Oomens J, Martens J, Coene KL. Untargeted metabolomics and infrared ion spectroscopy identify biomarkers for pyridoxine-dependent epilepsy. J Clin Invest 2021; 131:e148272. [PMID: 34138754 DOI: 10.1172/jci148272] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/16/2021] [Indexed: 12/30/2022] Open
Abstract
BackgroundPyridoxine-dependent epilepsy (PDE-ALDH7A1) is an inborn error of lysine catabolism that presents with refractory epilepsy in newborns. Biallelic ALDH7A1 variants lead to deficiency of α-aminoadipic semialdehyde dehydrogenase/antiquitin, resulting in accumulation of piperideine-6-carboxylate (P6C), and secondary deficiency of the important cofactor pyridoxal-5'-phosphate (PLP, active vitamin B6) through its complexation with P6C. Vitamin B6 supplementation resolves epilepsy in patients, but intellectual disability may still develop. Early diagnosis and treatment, preferably based on newborn screening, could optimize long-term clinical outcome. However, no suitable PDE-ALDH7A1 newborn screening biomarkers are currently available.MethodsWe combined the innovative analytical methods untargeted metabolomics and infrared ion spectroscopy to discover and identify biomarkers in plasma that would allow for PDE-ALDH7A1 diagnosis in newborn screening.ResultsWe identified 2S,6S-/2S,6R-oxopropylpiperidine-2-carboxylic acid (2-OPP) as a PDE-ALDH7A1 biomarker, and confirmed 6-oxopiperidine-2-carboxylic acid (6-oxoPIP) as a biomarker. The suitability of 2-OPP as a potential PDE-ALDH7A1 newborn screening biomarker in dried bloodspots was shown. Additionally, we found that 2-OPP accumulates in brain tissue of patients and Aldh7a1-knockout mice, and induced epilepsy-like behavior in a zebrafish model system.ConclusionThis study has opened the way to newborn screening for PDE-ALDH7A1. We speculate that 2-OPP may contribute to ongoing neurotoxicity, also in treated PDE-ALDH7A1 patients. As 2-OPP formation appears to increase upon ketosis, we emphasize the importance of avoiding catabolism in PDE-ALDH7A1 patients.FundingSociety for Inborn Errors of Metabolism for Netherlands and Belgium (ESN), United for Metabolic Diseases (UMD), Stofwisselkracht, Radboud University, Canadian Institutes of Health Research, Dutch Research Council (NWO), and the European Research Council (ERC).
Collapse
Affiliation(s)
- Udo Fh Engelke
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Jona Merx
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands
| | | | - Arno van Rooij
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Giel Berden
- Institute for Molecules and Materials, FELIX Laboratory and
| | - Marleen Cdg Huigen
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Leo Aj Kluijtmans
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Tessa Ma Peters
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Hilal H Al-Shekaili
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia, Canada
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, Department of Medical Genetics, University of British Columbia Vancouver, British Columbia, Canada
| | - Erik de Vrieze
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Sanne Broekman
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Laura A Tseng
- Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Purva Kulkarni
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Floris Pjt Rutjes
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands
| | - Jasmin Mecinović
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands.,Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Eduard A Struys
- Department of Clinical Chemistry, Amsterdam University Medical Centers, location VU Medical Centre, Amsterdam, Netherlands
| | - Laura A Jansen
- Division of Pediatric Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sidney M Gospe
- Departments of Neurology and Pediatrics, University of Washington, Seattle, Washington, USA.,Department of Pediatrics, Duke University, Durham, North Carolina, USA
| | - Saadet Mercimek-Andrews
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Keith Hyland
- Medical Neurogenetics Laboratories, Atlanta, Georgia, USA
| | - Michèl Aap Willemsen
- Department of Pediatric Neurology, Radboud University Medical Centre, Nijmegen, Netherlands
| | - Levinus A Bok
- Department of Pediatrics, Máxima Medical Centre, Veldhoven, Netherlands
| | - Clara Dm van Karnebeek
- Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, Netherlands.,Department of Pediatrics-Metabolic Diseases, Radboud Center for Mitochondrial Medicine, Radboud University Medical Center, Nijmegen, Netherlands.,United for Metabolic Diseases (UMD), Netherlands
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Thomas J Boltje
- Institute for Molecules and Materials, Synthetic Organic Chemistry, Radboud University, Nijmegen, Netherlands
| | - Jos Oomens
- Institute for Molecules and Materials, FELIX Laboratory and.,Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, Netherlands
| | | | - Karlien Lm Coene
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| |
Collapse
|
12
|
Yazdani M, Elgstøen KBP. Is oxidative stress an overlooked player in pyridoxine-dependent epilepsy? A focused review. Seizure 2021; 91:369-373. [PMID: 34298455 DOI: 10.1016/j.seizure.2021.07.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 01/22/2023] Open
Abstract
Pyridoxine-dependent epilepsy (PDE) is a rare autosomal recessive developmental and epileptic encephalopathy that is responsive to pharmacologic doses of vitamin B6. The deficiency of antiquitin, an enzyme involved in the catabolism of lysine, is believed to be its key molecular basis. Research to date has tended to focus on two known catabolic pathways of lysine, namely, saccharopine and pipecolic acid. However, the occurrence of oxidative stress and the presence of its metabolites have been only briefly highlighted in the literature. Owing to the importance of the topic and its potential for future diagnosis, prognosis and therapy, this paper reviews the suggested mechanisms of oxidative stress in antiquitin deficiency along with the proposed reactions and intermediates, and finally, discusses the challenges and opportunities.
Collapse
Affiliation(s)
- Mazyar Yazdani
- Metabolomics and Metabolic Molecular Biology Group, Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway.
| | - Katja Benedikte Prestø Elgstøen
- Metabolomics and Metabolic Molecular Biology Group, Department of Medical Biochemistry, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway
| |
Collapse
|
13
|
Cognitive and neurological outcome of patients in the Dutch pyridoxine-dependent epilepsy (PDE-ALDH7A1) cohort, a cross-sectional study. Eur J Paediatr Neurol 2021; 33:112-120. [PMID: 34153871 DOI: 10.1016/j.ejpn.2021.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 05/14/2021] [Accepted: 06/02/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Pyridoxine monotherapy in PDE-ALDH7A1 often results in adequate seizure control, but neurodevelopmental outcome varies. Detailed long-term neurological outcome is unknown. Here we present the cognitive and neurological features of the Dutch PDE-ALDH7A1 cohort. METHODS Neurological outcome was assessed in 24 patients (age 1-26 years); classified as normal, complex minor neurological dysfunction (complex MND) or abnormal. Intelligence quotient (IQ) was derived from standardized IQ tests with five severity levels of intellectual disability (ID). MRI's and treatments were assessed. RESULTS Ten patients (42%) showed unremarkable neurological examination, 11 (46%) complex MND, and 3 (12%) cerebral palsy (CP). Minor coordination problems were identified in 17 (71%), fine motor disability in 11 (46%), posture/muscle tone deviancies in 11 (46%) and abnormal reflexes in 8 (33%). Six patients (25%) had an IQ > 85, 7 (29%) borderline, 7 (29%) mild, 3 (13%) moderate, and 1 severe ID. Cerebral ventriculomegaly on MRI was progressive in 11. Three patients showed normal neurologic exam, IQ, and MRI. Eleven patients were treated with pyridoxine only and 13 by additional lysine reduction therapy (LRT). LRT started at age <3 years demonstrated beneficial effect on IQ results in 3 patients. DISCUSSION Complex MND and CP occurred more frequently in PDE-ALDH7A1 (46% and 12%) than in general population (7% and 0.2%, Peters et al., 2011, Schaefer et al., 2008). Twenty-five percent had a normal IQ. Although LRT shows potential to improve outcomes, data are heterogeneous in small patient numbers. More research with longer follow-up via the International PDE Registry (www.pdeonline.org) is needed.
Collapse
|