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Raslan IR, Silva TYT, Kok F, Rodrigues MM, Aragão MM, Pinho RS, França MC, Barsottini OG, Pedroso JL. Clinical and Genetic Characterization of a Cohort of Brazilian Patients With Congenital Ataxia. Neurol Genet 2024; 10:e200153. [PMID: 38681507 PMCID: PMC11052569 DOI: 10.1212/nxg.0000000000200153] [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: 08/28/2023] [Accepted: 02/29/2024] [Indexed: 05/01/2024]
Abstract
Background and Objectives Congenital ataxias are rare hereditary disorders characterized by hypotonia and developmental motor delay in the first few months of life, followed by cerebellar ataxia in early childhood. The course of the disease is predominantly nonprogressive, and many patients are incorrectly diagnosed with cerebral palsy. Despite significant advancements in next-generation sequencing in the past few decades, a specific genetic diagnosis is seldom obtained in cases of congenital ataxia. The aim of the study was to analyze the clinical, radiologic, and genetic features of a cohort of Brazilian patients with congenital ataxia. Methods Thirty patients with a clinical diagnosis of congenital ataxia were enrolled in this study. Clinical and demographic features and neuroimaging studies were analyzed. Genetic testing (whole-exome sequencing) was also performed. Results A heterogeneous pattern of genetic variants was detected. Eighteen genes were involved: ALDH5A1, BRF1, CACNA1A CACNA1G, CC2D2A, CWF19L1, EXOSC3, ITPR1, KIF1A, MME, PEX10, SCN2A, SNX14, SPTBN2, STXBP1, TMEM240, THG1L, and TUBB4A. Pathogenic/likely pathogenic variants involving 11 genes (ALDH5A1, CACNA1A, EXOSC3, MME, ITPR1, KIF1A, STXBP1, SNX14, SPTBN2, TMEM240, and TUBB4A) were identified in 46.7% of patients. Variants of uncertain significance involving 8 genes were detected in 33.3% of patients. Congenital ataxias were characterized by a broad phenotype. A genetic diagnosis was more often obtained in patients with cerebellar-plus syndrome than in patients with a pure cerebellar syndrome. Discussion This study re-emphasizes the genetic heterogeneity of congenital ataxias and the absence of a clear phenotype-genotype relationship. A specific genetic diagnosis was established in 46.7% of patients. Autosomal dominant, associated with sporadic cases, was recognized as an important genetic inheritance. The results of this analysis highlight the value of whole-exome sequencing as an efficient screening tool in patients with congenital ataxia.
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Affiliation(s)
- Ivana R Raslan
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - Thiago Yoshinaga Tonholo Silva
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - Fernando Kok
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - Marcelo M Rodrigues
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - Marcelo M Aragão
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - Ricardo S Pinho
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - Marcondes C França
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - Orlando G Barsottini
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
| | - José Luiz Pedroso
- From the Department of Ataxia Unit of the Federal University of São Paulo (UNIFESP) (I.R.R., T.Y.T.S., O.G.B., J.L.P.); Neurology Department (F.K.), Hospital das Clínicas da Universidade de São Paulo and Mendelics; Department of Neurology and Neurosurgery (M.M.R., M.M.A., R.S.P.), Universidade Federal de São Paulo (UNIFESP); and Department of Neurology (M.C.F.), Universidade de Campinas (UNICAMP), Brazil
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Tokatly Latzer I, Bertoldi M, Blau N, DiBacco ML, Elsea SH, García-Cazorla À, Gibson KM, Gropman AL, Hanson E, Hoffman C, Jeltsch K, Juliá-Palacios N, Knerr I, Lee HHC, Malaspina P, McConnell A, Opladen T, Oppebøen M, Rotenberg A, Walterfang M, Wang-Tso L, Wevers RA, Roullet JB, Pearl PL. Consensus guidelines for the diagnosis and management of succinic semialdehyde dehydrogenase deficiency. Mol Genet Metab 2024; 142:108363. [PMID: 38452608 PMCID: PMC11073920 DOI: 10.1016/j.ymgme.2024.108363] [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: 11/17/2023] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 03/09/2024]
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD) (OMIM #271980) is a rare autosomal recessive metabolic disorder caused by pathogenic variants of ALDH5A1. Deficiency of SSADH results in accumulation of γ-aminobutyric acid (GABA) and other GABA-related metabolites. The clinical phenotype of SSADHD includes a broad spectrum of non-pathognomonic symptoms such as cognitive disabilities, communication and language deficits, movement disorders, epilepsy, sleep disturbances, attention problems, anxiety, and obsessive-compulsive traits. Current treatment options for SSADHD remain supportive, but there are ongoing attempts to develop targeted genetic therapies. This study aimed to create consensus guidelines for the diagnosis and management of SSADHD. Thirty relevant statements were initially addressed by a systematic literature review, resulting in different evidence levels of strength according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. The highest level of evidence (level A), based on randomized controlled trials, was unavailable for any of the statements. Based on cohort studies, Level B evidence was available for 12 (40%) of the statements. Thereupon, through a process following the Delphi Method and directed by the Appraisal of Guidelines for Research and Evaluation (AGREE II) criteria, expert opinion was sought, and members of an SSADHD Consensus Group evaluated all the statements. The group consisted of neurologists, epileptologists, neuropsychologists, neurophysiologists, metabolic disease specialists, clinical and biochemical geneticists, and laboratory scientists affiliated with 19 institutions from 11 countries who have clinical experience with SSADHD patients and have studied the disorder. Representatives from parent groups were also included in the Consensus Group. An analysis of the survey's results yielded 25 (83%) strong and 5 (17%) weak agreement strengths. These first-of-their-kind consensus guidelines intend to consolidate and unify the optimal care that can be provided to individuals with SSADHD.
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Affiliation(s)
- Itay Tokatly Latzer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; School of Medicine, Faculty of Medicine and Health Sciences, Tel-Aviv University, Tel Aviv, Israel.
| | - Mariarita Bertoldi
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Italy.
| | - Nenad Blau
- Division of Metabolism, University Children's Hospital, Zürich, Switzerland; Children's Research Center, University Children's Hospital Zurich, Switzerland.
| | - Melissa L DiBacco
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
| | - Àngels García-Cazorla
- Neurometabolic Unit, Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu, Barcelona, Spain.
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA.
| | - Andrea L Gropman
- Division of Neurogenetics and Neurodevelopmental Disabilities, Children's National Hospital, Washington, D.C, USA.
| | - Ellen Hanson
- Human Neurobehavioral Core, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, MA 02115, USA.
| | | | - Kathrin Jeltsch
- Heidelberg University, Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg, Germany.
| | - Natalia Juliá-Palacios
- Neurometabolic Unit, Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu, Barcelona, Spain.
| | - Ina Knerr
- National Centre for Inherited Metabolic Disorders, Children's Health Ireland, Temple Street, Dublin, Ireland.
| | - Henry H C Lee
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA.
| | - Patrizia Malaspina
- Department of Biology, Tor Vergata University, Via della Ricerca Scientifica s.n.c., Rome 00133, Italy.
| | | | - Thomas Opladen
- Heidelberg University, Medical Faculty Heidelberg, Center for Pediatric and Adolescent Medicine, Department I, Division of Pediatric Neurology and Metabolic Medicine, Heidelberg, Germany.
| | | | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA.
| | - Mark Walterfang
- Neuropsychiatry, Royal Melbourne Hospital, Melbourne, Australia; Department of Psychiatry, University of Melbourne, Melbourne, Australia; Florey Institute of Neuroscience and Mental Health, Melbourne, Australia; Department of Health and Medical Sciences, Edith Cowan University, Perth, Australia.
| | - Lee Wang-Tso
- Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
| | - Ron A Wevers
- Translational Metabolic Laboratory, Department Human Genetics, Radboud University Medical Centre, Nijmegen, the Netherlands.
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA.
| | - Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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Liu N, Kong XD, Kan QC, Shi HR, Wu QH, Zhuo ZH, Bai QL, Jiang M. Mutation analysis and prenatal diagnosis in a Chinese family with succinic semialdehyde dehydrogenase and a systematic review of the literature of reported ALDH5A1 mutations. J Perinat Med 2016; 44:441-51. [PMID: 25431891 DOI: 10.1515/jpm-2014-0164] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 10/23/2014] [Indexed: 11/15/2022]
Abstract
AIMS Succinic semialdehyde dehydrogenase (SSADH) deficiency is a neurometabolic disease in which the degradation of γ-aminobutyric acid (GABA) is impaired. The purpose of this study was to report two novel ALDH5A1 mutations responsible for SSADH deficiency in a Chinese family and the prenatal diagnosis of an at-risk fetus with DNA sequencing. RESULTS Genetic analysis of ALDH5A1, in a child with SSADH deficiency, parents, and 10 weeks' gestation at-risk fetus and 100 healthy unrelated volunteers, was performed. The coding sequence and the intron/exon junctions of ALDH5A1 were analyzed by bidirectional DNA sequencing. The proband was identified to have a compound heterozygous mutations with c.496T>C (p.W166R) and c.589G>A (p.V197M). Each of his parents carried a deleterious mutation. DNA sequencing of chorionic villus revealed the fetus was a carrier, but not affected, and this was confirmed after birth by genetic analysis of umbilical cord blood and urine organic acid analysis. A study in 2003 described 35 mutations of ALDH5A1 in 54 unrelated families, and the current study and systematic literature review identified nine additional novel mutations in eight unrelated families bringing the total number of unique mutations of ALDH5A1 resulting in SSADH deficiency to 44, and the 44 mutations occur from exon 1 to exon 10. No mutational hotspots or prevalent mutations were observed, and all mutations appeared vital for the function of SSADH. CONCLUSIONS Two novel ALDH5A1 mutations likely responsible for SSADH deficiency were identified, and DNA sequencing provided an accurate diagnosis for an at-risk fetus whose sibling had SSADH deficiency.
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Tay CG, Ariffin H, Yap S, Rahmat K, Sthaneshwar P, Ong LC. Succinic Semialdehyde Dehydrogenase Deficiency in a Chinese Boy: A Novel ALDH5A1 Mutation With Severe Phenotype. J Child Neurol 2015; 30:927-31. [PMID: 25122112 DOI: 10.1177/0883073814540523] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 05/22/2014] [Indexed: 11/15/2022]
Abstract
Succinic semialdehyde dehydrogenase deficiency is a rare autosomal recessive disorder affecting catabolism of the neurotransmitter gamma-aminobutyric acid (GABA), with a wide range of clinical phenotype. We report a Malaysian Chinese boy with a severe early onset phenotype due to a previously unreported mutation. Urine organic acid chromatogram revealed elevated 4-hydroxybutyric acid. Magnetic resonance imaging (MRI) of the brain demonstrated cerebral atrophy with atypical putaminal involvement. Molecular genetic analysis showed a novel homozygous 3-bp deletion at the ALDH5A1 gene c.1501_1503del (p.Glu501del). Both parents were confirmed to be heterozygotes for the p.Glu501del mutation. The clinical course was complicated by the development of subdural hemorrhage probably as a result of rocking the child to sleep for erratic sleep-wake cycles. This case illustrates the need to recognize that trivial or unintentional shaking of such children, especially in the presence of cerebral atrophy, can lead to subdural hemorrhage.
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Affiliation(s)
- Chee Geap Tay
- Department of Paediatrics, Faculty of Medicine, University Malaya, Malaysia
| | - Hany Ariffin
- Department of Paediatrics, Faculty of Medicine, University Malaya, Malaysia University of Malaya Cancer Research Institute, University Malaya, Malaysia
| | - Sufin Yap
- Department of Paediatrics, Faculty of Medicine, University Malaya, Malaysia Department of Metabolic Medicine, Sheffield Children's Hospital, NHS Foundation Trust, Western Bank, Sheffield, United Kingdom
| | - Kartini Rahmat
- Department of Biomedical Imaging, University Malaya Research Imaging Centre, University Malaya, Malaysia
| | - Pavai Sthaneshwar
- Department of Pathology, Faculty of Medicine, University Malaya, Malaysia
| | - Lai Choo Ong
- Department of Paediatrics, Faculty of Medicine, University Malaya, Malaysia
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Kim KJ, Pearl PL, Jensen K, Snead OC, Malaspina P, Jakobs C, Gibson KM. Succinic semialdehyde dehydrogenase: biochemical-molecular-clinical disease mechanisms, redox regulation, and functional significance. Antioxid Redox Signal 2011; 15:691-718. [PMID: 20973619 PMCID: PMC3125545 DOI: 10.1089/ars.2010.3470] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH; aldehyde dehydrogenase 5a1, ALDH5A1; E.C. 1.2.1.24; OMIM 610045, 271980) deficiency is a rare heritable disorder that disrupts the metabolism of the inhibitory neurotransmitter 4-aminobutyric acid (GABA). Identified in conjunction with increased urinary excretion of the GABA analog gamma-hydroxybutyric acid (GHB), numerous patients have been identified worldwide and the autosomal-recessive disorder has been modeled in mice. The phenotype is one of nonprogressive neurological dysfunction in which seizures may be prominently displayed. The murine model is a reasonable phenocopy of the human disorder, yet the severity of the seizure disorder in the mouse exceeds that observed in SSADH-deficient patients. Abnormalities in GABAergic and GHBergic neurotransmission, documented in patients and mice, form a component of disease pathophysiology, although numerous other disturbances (metabolite accumulations, myelin abnormalities, oxidant stress, neurosteroid depletion, altered bioenergetics, etc.) are also likely to be involved in developing the disease phenotype. Most recently, the demonstration of a redox control system in the SSADH protein active site has provided new insights into the regulation of SSADH by the cellular oxidation/reduction potential. The current review summarizes some 30 years of research on this protein and disease, addressing pathological mechanisms in human and mouse at the protein, metabolic, molecular, and whole-animal level.
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Affiliation(s)
- Kyung-Jin Kim
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Phillip L. Pearl
- Department of Neurology, Children's National Medical Center, Washington, District of Columbia
| | - Kimmo Jensen
- Synaptic Physiology Laboratory, Department of Physiology and Biophysics, Aarhus University, Aarhus, Denmark
- Center for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
| | - O. Carter Snead
- Department of Neurology, Hospital for Sick Children and University of Toronto, Toronto, Ontario, Canada
| | | | - Cornelis Jakobs
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - K. Michael Gibson
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan
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Langendorf CG, Key TLG, Fenalti G, Kan WT, Buckle AM, Caradoc-Davies T, Tuck KL, Law RHP, Whisstock JC. The X-ray crystal structure of Escherichia coli succinic semialdehyde dehydrogenase; structural insights into NADP+/enzyme interactions. PLoS One 2010; 5:e9280. [PMID: 20174634 PMCID: PMC2823781 DOI: 10.1371/journal.pone.0009280] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Accepted: 01/23/2010] [Indexed: 01/14/2023] Open
Abstract
Background In mammals succinic semialdehyde dehydrogenase (SSADH) plays an essential role in the metabolism of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) to succinic acid (SA). Deficiency of SSADH in humans results in elevated levels of GABA and γ-Hydroxybutyric acid (GHB), which leads to psychomotor retardation, muscular hypotonia, non-progressive ataxia and seizures. In Escherichia coli, two genetically distinct forms of SSADHs had been described that are essential for preventing accumulation of toxic levels of succinic semialdehyde (SSA) in cells. Methodology/Principal Findings Here we structurally characterise SSADH encoded by the E coli gabD gene by X-ray crystallographic studies and compare these data with the structure of human SSADH. In the E. coli SSADH structure, electron density for the complete NADP+ cofactor in the binding sites is clearly evident; these data in particular revealing how the nicotinamide ring of the cofactor is positioned in each active site. Conclusions/Significance Our structural data suggest that a deletion of three amino acids in E. coli SSADH permits this enzyme to use NADP+, whereas in contrast the human enzyme utilises NAD+. Furthermore, the structure of E. coli SSADH gives additional insight into human mutations that result in disease.
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Affiliation(s)
- Christopher G. Langendorf
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria, Australia
| | - Trevor L. G. Key
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria, Australia
- School of Chemistry, Monash University, Clayton Campus, Melbourne, Victoria, Australia
| | - Gustavo Fenalti
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria, Australia
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Wan-Ting Kan
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria, Australia
- ARC Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Melbourne, Victoria, Australia
| | - Ashley M. Buckle
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria, Australia
| | | | - Kellie L. Tuck
- School of Chemistry, Monash University, Clayton Campus, Melbourne, Victoria, Australia
| | - Ruby H. P. Law
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria, Australia
- ARC Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Melbourne, Victoria, Australia
- * E-mail: (RHPL); (JCW)
| | - James C. Whisstock
- Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria, Australia
- ARC Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Melbourne, Victoria, Australia
- * E-mail: (RHPL); (JCW)
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Comparative genomics of aldehyde dehydrogenase 5a1 (succinate semialdehyde dehydrogenase) and accumulation of gamma-hydroxybutyrate associated with its deficiency. Hum Genomics 2009; 3:106-20. [PMID: 19164088 PMCID: PMC2657722 DOI: 10.1186/1479-7364-3-2-106] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Succinic semialdehyde dehydrogenase (SSADH; aldehyde dehydrogenase 5A1 [ALDH5A1]; locus 6p22) occupies a central position in central nervous system (CNS) neurotransmitter metabolism as one of two enzymes necessary for γ-aminobutyric acid (GABA) recycling from the synaptic cleft. Its importance is highlighted by the neurometabolic disease associated with its inherited deficiency in humans, as well as the severe epileptic phenotype observed in Aldh5a1-/- knockout mice. Expanding evidence now suggests, however, that even subtle decreases in human SSADH activity, associated with rare and common single nucleotide polymorphisms, may produce subclinical pathological effects. SSADH, in conjunction with aldo-keto reductase 7A2 (AKR7A2), represent two neural enzymes responsible for further catabolism of succinic semialdehyde, producing either succinate (SSADH) or γ-hydroxybutyrate (GHB; AKR7A2). A GABA analogue, GHB is a short-chain fatty alcohol with unusual properties in the CNS and a long pharmacological history. Moreover, SSADH occupies a further role in the CNS as the enzyme responsible for further metabolism of the lipid peroxidation aldehyde 4-hydroxy-2-nonenal (4-HNE), an intermediate known to induce oxidant stress. Accordingly, subtle decreases in SSADH activity may have the capacity to lead to regional accumulation of neurotoxic intermediates (GHB, 4-HNE). Polymorphisms in SSADH gene structure may also associate with quantitative traits, including intelligence quotient and life expectancy. Further population-based studies of human SSADH activity promise to reveal additional properties of its function and additional roles in CNS tissue.
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