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Tokatly Latzer I, Roullet JB, Cesaro S, DiBacco ML, Arning E, Rotenberg A, Lee HHC, Opladen T, Jeltsch K, García-Cazorla À, Juliá-Palacios N, Gibson KM, Bertoldi M, Pearl PL. Phenotypic correlates of structural and functional protein impairments resultant from ALDH5A1 variants. Hum Genet 2023; 142:1755-1776. [PMID: 37962671 DOI: 10.1007/s00439-023-02613-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023]
Abstract
To investigate the genotype-to-protein-to-phenotype correlations of succinic semialdehyde dehydrogenase deficiency (SSADHD), an inherited metabolic disorder of γ-aminobutyric acid catabolism. Bioinformatics and in silico mutagenesis analyses of ALDH5A1 variants were performed to evaluate their impact on protein stability, active site and co-factor binding domains, splicing, and homotetramer formation. Protein abnormalities were then correlated with a validated disease-specific clinical severity score and neurological, neuropsychological, biochemical, neuroimaging, and neurophysiological metrics. A total of 58 individuals (1:1 male/female ratio) were affected by 32 ALDH5A1 pathogenic variants, eight of which were novel. Compared to individuals with single homotetrameric or multiple homo and heterotetrameric proteins, those predicted not to synthesize any functional enzyme protein had significantly lower expression of ALDH5A1 (p = 0.001), worse overall clinical outcomes (p = 0.008) and specifically more severe cognitive deficits (p = 0.01), epilepsy (p = 0.04) and psychiatric morbidity (p = 0.04). Compared to individuals with predictions of having no protein or a protein impaired in catalytic functions, subjects whose proteins were predicted to be impaired in stability, folding, or oligomerization had a better overall clinical outcome (p = 0.02) and adaptive skills (p = 0.04). The quantity and type of enzyme proteins (no protein, single homotetramers, or multiple homo and heterotetramers), as well as their structural and functional impairments (catalytic or stability, folding, or oligomerization), contribute to phenotype severity in SSADHD. These findings are valuable for assessment of disease prognosis and management, including patient selection for gene replacement therapy. Furthermore, they provide a roadmap to determine genotype-to-protein-to-phenotype relationships in other autosomal recessive disorders.
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Affiliation(s)
- Itay Tokatly Latzer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
- Faculty of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Samuele Cesaro
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, 37134, Verona, VR, Italy
| | - Melissa L DiBacco
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
| | - Erland Arning
- Institute of Metabolic Disease, Baylor Scott & White Research Institute, Dallas, TX, USA
| | - Alexander Rotenberg
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Henry H C Lee
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Thomas Opladen
- Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Kathrin Jeltsch
- Division of Neuropediatrics and Metabolic Medicine, University Children's Hospital Heidelberg, Im Neuenheimer Feld 430, 69120, Heidelberg, Germany
| | - Àngels García-Cazorla
- Neurometabolic Unit, Neurology Department, Institut de Recerca, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Natalia Juliá-Palacios
- 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
| | - Mariarita Bertoldi
- Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, 37134, Verona, VR, Italy.
| | - Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA.
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Ciminelli BM, Menduti G, Benussi L, Ghidoni R, Binetti G, Squitti R, Rongioletti M, Nica S, Novelletto A, Rossi L, Malaspina P. Polymorphic Genetic Markers of the GABA Catabolism Pathway in Alzheimer's Disease. J Alzheimers Dis 2020; 77:301-311. [PMID: 32804142 DOI: 10.3233/jad-200429] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND The compilation of a list of genetic modifiers in Alzheimer's disease (AD) is an open research field. The GABAergic system is affected in several neurological disorders but its role in AD is largely understudied. OBJECTIVE/METHODS As an explorative study, we considered variants in genes of GABA catabolism (ABAT, ALDH5A1, AKR7A2), and APOE in 300 Italian patients and 299 controls. We introduce a recent multivariate method to take into account the individual APOE genotype, thus controlling for the effect of the discrepant allele distributions in cases versus controls. We add a genotype-phenotype analysis based on age at onset and the Mini-Mental State Evaluation score. RESULTS On the background of strongly divergent APOE allele distributions in AD versus controls, two genotypic interactions that represented a subtle but significant peculiarity of the AD cohort emerged. The first is between ABAT and APOE, and the second between some ALDH5A1 genotypes and APOE. Decreased SSADH activity is predicted in AD carriers of APOEɛ4, representing an additional suggestion for increased oxidative damage. CONCLUSION We identified a difference between AD and controls, not in a shift of the allele frequencies at genes of the GABA catabolism pathway, but rather in gene interactions peculiar of the AD cohort. The emerging view is that of a multifactorial contribution to the disease, with a main risk factor (APOE), and additional contributions by the variants here considered. We consider genes of the GABA degradation pathway good candidates as modifiers of AD, contributing to energy impairment in AD brain.
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Affiliation(s)
| | | | - Luisa Benussi
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Roberta Ghidoni
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Giuliano Binetti
- MAC Memory Clinic and Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Rosanna Squitti
- Molecular Markers Laboratory, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Mauro Rongioletti
- Department of Laboratory Medicine, Research and Development Division, Fatebenefratelli Hospital, Isola Tiberina, Rome, Italy
| | - Sabrina Nica
- Department of Biology, University of Rome Tor Vergata, Italy
| | | | - Luisa Rossi
- Department of Biology, University of Rome Tor Vergata, Italy
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3
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Menduti G, Biamino E, Vittorini R, Vesco S, Puccinelli MP, Porta F, Capo C, Leo S, Ciminelli BM, Iacovelli F, Spada M, Falconi M, Malaspina P, Rossi L. Succinic semialdehyde dehydrogenase deficiency: The combination of a novel ALDH5A1 gene mutation and a missense SNP strongly affects SSADH enzyme activity and stability. Mol Genet Metab 2018; 124:210-215. [PMID: 29895405 DOI: 10.1016/j.ymgme.2018.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/28/2018] [Accepted: 05/30/2018] [Indexed: 02/06/2023]
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare autosomal recessive metabolic disorder of GABA catabolism. SSADH is a mitochondrial homotetrameric enzyme encoded by ALDH5A1 gene. We report the molecular characterization of ALDH5A1 gene in an Italian SSADHD patient, showing heterozygosity for four missense mutations: c.526G>A (p.G176R), c.538C>T (p.H180Y), c.709G>T (p.A237S) and c.1267A>T (p.T423S), the latter never described so far. The patient inherited c.526A in cis with c.538T from the mother and c.709T in cis with c.1267T from the father. To explore the effects of the two allelic arrangements on SSADH activity and protein level, wild type, single or double mutated cDNA constructs were expressed in a cell system. The p.G176R change, alone or in combination with p.H180Y, causes the abolishment of enzyme activity. Western blot analysis showed a strongly reduced amount of the p.176R-p.180Y double mutant protein, suggesting increased degradation. Indeed, in silico analyses confirmed high instability of this mutant homotetramer. Enzyme activity relative to the other p.423S-p.237S double mutant is around 30% of wt. Further in silico analyses on all the possible combinations of mutant monomers suggest the lowest stability for the tetramer constituted by p.176R-p.180Y monomers and the highest stability for that constituted by p.237S-p.423S monomers. The present study shows that when a common SNP, associated with a slight reduction of SSADH activity, is inherited in cis with a mutation showing no consequences on the enzyme function, the activity is strongly affected. In conclusion, the peculiar arrangement of four missense mutations occurring in this patient is responsible for the SSADHD phenotype.
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Affiliation(s)
| | - Elisa Biamino
- Department of Pediatrics, University of Turin, Italy
| | - Roberta Vittorini
- Department of Pediatric Neurology, Regina Margherita Children Hospital, University of Turin, Italy
| | - Serena Vesco
- Department of Pediatric Neurology, Regina Margherita Children Hospital, University of Turin, Italy
| | - Maria Paola Puccinelli
- Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza, Turin, Italy
| | | | - Concetta Capo
- Department of Biology, University of Rome Tor Vergata, Italy
| | - Sara Leo
- Department of Biology, University of Rome Tor Vergata, Italy
| | | | | | - Marco Spada
- Department of Pediatrics, University of Turin, Italy
| | - Mattia Falconi
- Department of Biology, University of Rome Tor Vergata, Italy
| | | | - Luisa Rossi
- Department of Biology, University of Rome Tor Vergata, Italy.
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4
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Malaspina P, Roullet JB, Pearl PL, Ainslie GR, Vogel KR, Gibson KM. Succinic semialdehyde dehydrogenase deficiency (SSADHD): Pathophysiological complexity and multifactorial trait associations in a rare monogenic disorder of GABA metabolism. Neurochem Int 2016; 99:72-84. [PMID: 27311541 DOI: 10.1016/j.neuint.2016.06.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022]
Abstract
Discovered some 35 years ago, succinic semialdehyde dehydrogenase deficiency (SSADHD) represents a rare, autosomal recessively-inherited defect in the second step of the GABA degradative pathway. Some 200 patients have been reported, with broad phenotypic and genotypic heterogeneity. SSADHD represents an unusual neurometabolic disorder in which two neuromodulatory agents, GABA (and the GABA analogue, 4-hydroxybutyrate), accumulate to supraphysiological levels. The unexpected occurrence of epilepsy in several patients is counterintuitive in view of the hyperGABAergic state, in which sedation might be expected. However, the epileptic status of some patients is most likely represented by broader imbalances of GABAergic and glutamatergic neurotransmission. Cumulative research encompassing decades of basic and clinical study of SSADHD reveal a monogenic disease with broad pathophysiological and clinical phenotypes. Numerous metabolic perturbations unmasked in SSADHD include alterations in oxidative stress parameters, dysregulation of autophagy and mitophagy, dysregulation of both inhibitory and excitatory neurotransmitters and gene expression, and unique subsets of SNP alterations of the SSADH gene (so-called ALDH5A1, or aldehyde dehydrogenase 5A1 gene) on the 6p22 chromosomal arm. While seemingly difficult to collate and interpret, these anomalies have continued to open novel pathways for pharmacotherapeutic considerations. Here, we present an update on selected aspects of SSADHD, the ALDH5A1 gene, and future avenues for research on this rare disorder of GABA metabolism.
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Affiliation(s)
- P Malaspina
- Department of Biology, University "Tor Vergata", Rome, Italy
| | - J-B Roullet
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - P L Pearl
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | - G R Ainslie
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - K R Vogel
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, USA
| | - K M Gibson
- Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Spokane, WA, 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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6
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Kos MZ, Glahn DC, Carless MA, Olvera R, McKay DR, Quillen EE, Gelernter J, Chen XD, Deng HW, Kent JW, Dyer TD, Göring HH, Curran JE, Duggirala R, Blangero J, Almasy L. Novel QTL at chromosome 6p22 for alcohol consumption: Implications for the genetic liability of alcohol use disorders. Am J Med Genet B Neuropsychiatr Genet 2014; 165B:294-302. [PMID: 24692236 PMCID: PMC4172449 DOI: 10.1002/ajmg.b.32231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 03/10/2014] [Indexed: 02/01/2023]
Abstract
Linkage studies of alcoholism have implicated several chromosome regions, leading to the successful identification of susceptibility genes, including ADH4 and GABRA2 on chromosome 4. Quantitative endophenotypes that are potentially closer to gene action than clinical endpoints offer a means of obtaining more refined linkage signals of genes that predispose alcohol use disorders (AUD). In this study we examine a self-reported measure of the maximum number of drinks consumed in a 24-hr period (abbreviated Max Drinks), a significantly heritable phenotype (h(2) = 0.32 ± 0.05; P = 4.61 × 10(-14)) with a strong genetic correlation with AUD (ρg = 0.99 ± 0.13) for the San Antonio Family Study (n = 1,203). Genome-wide SNPs were analyzed using variance components linkage methods in the program SOLAR, revealing a novel, genome-wide significant QTL (LOD = 4.17; P = 5.85 × 10(-6)) for Max Drinks at chromosome 6p22.3, a region with a number of compelling candidate genes implicated in neuronal function and psychiatric illness. Joint analysis of Max Drinks and AUD status shows that the QTL has a significant non-zero effect on diagnosis (P = 4.04 × 10(-3)), accounting for 8.6% of the total variation. Significant SNP associations for Max Drinks were also identified at the linkage region, including one, rs7761213 (P = 2.14 × 10(-4)), obtained for an independent sample of Chinese families. Thus, our study identifies a potential risk locus for AUD at 6p22.3, with significant pleiotropic effects on the heaviness of alcohol consumption that may not be population specific.
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Affiliation(s)
- Mark Z. Kos
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA,Correspondence to: Dr. M.Z. Kos, Department of Genetics, Texas Biomedical Research Institute, 7620 N.W. Loop 410, San Antonio, TX 78227, USA,
| | - David C. Glahn
- Olin Neuropsychiatry Research Center, Institute of Living, Hartford Hospital, Hartford, CT, USA
| | - Melanie A. Carless
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Rene Olvera
- Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX, USA
| | - D. Reese McKay
- Olin Neuropsychiatry Research Center, Institute of Living, Hartford Hospital, Hartford, CT, USA
| | - Ellen E. Quillen
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Joel Gelernter
- Department of Psychiatry, Yale University School of Medicine, West Haven, CT, USA
| | - Xiang-Ding Chen
- College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Hong-Wen Deng
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Jack W. Kent
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Thomas D. Dyer
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Harald H.H. Göring
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Joanne E. Curran
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Ravi Duggirala
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - John Blangero
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Laura Almasy
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
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7
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Benjamin DJ, Cesarini D, Chabris CF, Glaeser EL, Laibson DI, Guðnason V, Harris TB, Launer LJ, Purcell S, Smith AV, Johannesson M, Magnusson PKE, Beauchamp JP, Christakis NA, Atwood CS, Hebert B, Freese J, Hauser RM, Hauser TS, Grankvist A, Hultman CM, Lichtenstein P. The Promises and Pitfalls of Genoeconomics*. ANNUAL REVIEW OF ECONOMICS 2012; 4:627-662. [PMID: 23482589 PMCID: PMC3592970 DOI: 10.1146/annurev-economics-080511-110939] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This article reviews existing research at the intersection of genetics and economics, presents some new findings that illustrate the state of genoeconomics research, and surveys the prospects of this emerging field. Twin studies suggest that economic outcomes and preferences, once corrected for measurement error, appear to be about as heritable as many medical conditions and personality traits. Consistent with this pattern, we present new evidence on the heritability of permanent income and wealth. Turning to genetic association studies, we survey the main ways that the direct measurement of genetic variation across individuals is likely to contribute to economics, and we outline the challenges that have slowed progress in making these contributions. The most urgent problem facing researchers in this field is that most existing efforts to find associations between genetic variation and economic behavior are based on samples that are too small to ensure adequate statistical power. This has led to many false positives in the literature. We suggest a number of possible strategies to improve and remedy this problem: (a) pooling data sets, (b) using statistical techniques that exploit the greater information content of many genes considered jointly, and (c) focusing on economically relevant traits that are most proximate to known biological mechanisms.
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Affiliation(s)
- Daniel J Benjamin
- Department of Economics, Cornell University, Ithaca, New York 14853; National Bureau of Economic Research, Cambridge, Massachusetts 02138;
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8
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Luciano M, Batty GD, McGilchrist M, Linksted P, Fitzpatrick B, Jackson C, Pattie A, Dominiczak AF, Morris AD, Smith BH, Porteous D, Deary IJ. Shared genetic aetiology between cognitive ability and cardiovascular disease risk factors: Generation Scotland's Scottish family health study. INTELLIGENCE 2010. [DOI: 10.1016/j.intell.2010.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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9
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Crespi B, Summers K, Dorus S. Evolutionary genomics of human intellectual disability. Evol Appl 2010; 3:52-63. [PMID: 25567903 PMCID: PMC3352458 DOI: 10.1111/j.1752-4571.2009.00098.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Accepted: 07/28/2009] [Indexed: 01/28/2023] Open
Abstract
Previous studies have postulated that X-linked and autosomal genes underlying human intellectual disability may have also mediated the evolution of human cognition. We have conducted the first comprehensive assessment of the extent and patterns of positive Darwinian selection on intellectual disability genes in humans. We report three main findings. First, as noted in some previous reports, intellectual disability genes with primary functions in the central nervous system exhibit a significant concentration to the X chromosome. Second, there was no evidence for a higher incidence of recent positive selection on X-linked than autosomal intellectual disability genes, nor was there a higher incidence of selection on such genes overall, compared to sets of control genes. However, the X-linked intellectual disability genes inferred to be subject to recent positive selection were concentrated in the Rho GTP-ase pathway, a key signaling pathway in neural development and function. Third, among all intellectual disability genes, there was evidence for a higher incidence of recent positive selection on genes involved in DNA repair, but not for genes involved in other functions. These results provide evidence that alterations to genes in the Rho GTP-ase and DNA-repair pathways may play especially-important roles in the evolution of human cognition and vulnerability to genetically-based intellectual disability.
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Affiliation(s)
- Bernard Crespi
- Department of Biosciences, Simon Fraser UniversityBurnaby, BC, Canada
| | - Kyle Summers
- Department of Biology, East Carolina UniversityGreenville, NC, USA
| | - Steve Dorus
- Department of Biology and Biochemistry, University of BathBath, UK
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10
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Payton A. The Impact of Genetic Research on our Understanding of Normal Cognitive Ageing: 1995 to 2009. Neuropsychol Rev 2009; 19:451-77. [DOI: 10.1007/s11065-009-9116-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Accepted: 08/17/2009] [Indexed: 12/11/2022]
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11
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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: 26] [Impact Index Per Article: 1.7] [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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