1
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Biancaniello C, D'Argenio A, Giordano D, Dotolo S, Scafuri B, Marabotti A, d'Acierno A, Tagliaferri R, Facchiano A. Investigating the Effects of Amino Acid Variations in Human Menin. Molecules 2022; 27:1747. [PMID: 35268848 PMCID: PMC8911756 DOI: 10.3390/molecules27051747] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/01/2022] [Accepted: 03/04/2022] [Indexed: 12/14/2022] Open
Abstract
Human menin is a nuclear protein that participates in many cellular processes, as transcriptional regulation, DNA damage repair, cell signaling, cell division, proliferation, and migration, by interacting with many other proteins. Mutations of the gene encoding menin cause multiple endocrine neoplasia type 1 (MEN1), a rare autosomal dominant disorder associated with tumors of the endocrine glands. In order to characterize the structural and functional effects at protein level of the hundreds of missense variations, we investigated by computational methods the wild-type menin and more than 200 variants, predicting the amino acid variations that change secondary structure, solvent accessibility, salt-bridge and H-bond interactions, protein thermostability, and altering the capability to bind known protein interactors. The structural analyses are freely accessible online by means of a web interface that integrates also a 3D visualization of the structure of the wild-type and variant proteins. The results of the study offer insight into the effects of the amino acid variations in view of a more complete understanding of their pathological role.
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Affiliation(s)
- Carmen Biancaniello
- Dipartimento di Scienze Aziendali, Management and Innovation Systems, Università degli Studi di Salerno, 84084 Fisciano, Italy
| | - Antonia D'Argenio
- National Research Council, Institute of Food Science, 83100 Avellino, Italy
| | - Deborah Giordano
- National Research Council, Institute of Food Science, 83100 Avellino, Italy
| | - Serena Dotolo
- Dipartimento di Scienze Aziendali, Management and Innovation Systems, Università degli Studi di Salerno, 84084 Fisciano, Italy
| | - Bernardina Scafuri
- Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno, 84084 Fisciano, Italy
| | - Anna Marabotti
- Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno, 84084 Fisciano, Italy
| | - Antonio d'Acierno
- National Research Council, Institute of Food Science, 83100 Avellino, Italy
| | - Roberto Tagliaferri
- Dipartimento di Scienze Aziendali, Management and Innovation Systems, Università degli Studi di Salerno, 84084 Fisciano, Italy
| | - Angelo Facchiano
- National Research Council, Institute of Food Science, 83100 Avellino, Italy
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2
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Verdino A, D’Urso G, Tammone C, Scafuri B, Catapano L, Marabotti A. Simulation of the Interactions of Arginine with Wild-Type GALT Enzyme and the Classic Galactosemia-Related Mutant p.Q188R by a Computational Approach. Molecules 2021; 26:6061. [PMID: 34641605 PMCID: PMC8513022 DOI: 10.3390/molecules26196061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/30/2021] [Accepted: 10/05/2021] [Indexed: 11/18/2022] Open
Abstract
Classic galactosemia is an inborn error of metabolism associated with mutations that impair the activity and the stability of galactose-1-phosphate uridylyltransferase (GALT), catalyzing the third step in galactose metabolism. To date, no treatments (including dietary galactose deprivation) are able to prevent or alleviate the long-term complications affecting galactosemic patients. Evidence that arginine is able to improve the activity of the human enzyme expressed in a prokaryotic model of classic galactosemia has induced researchers to suppose that this amino acid could act as a pharmacochaperone, but no effects were detected in four galactosemic patients treated with this amino acid. Given that no molecular characterizations of the possible effects of arginine on GALT have been performed, and given that the samples of patients treated with arginine are extremely limited for drawing definitive conclusions at the clinical level, we performed computational simulations in order to predict the interactions (if any) between this amino acid and the enzyme. Our results do not support the possibility that arginine could function as a pharmacochaperone for GALT, but information obtained by this study could be useful for identifying, in the future, possible pharmacochaperones for this enzyme.
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Affiliation(s)
- Anna Verdino
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy; (A.V.); (G.D.); (C.T.); (B.S.); (L.C.)
| | - Gaetano D’Urso
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy; (A.V.); (G.D.); (C.T.); (B.S.); (L.C.)
| | - Carmen Tammone
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy; (A.V.); (G.D.); (C.T.); (B.S.); (L.C.)
| | - Bernardina Scafuri
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy; (A.V.); (G.D.); (C.T.); (B.S.); (L.C.)
- Interuniversity Center “ELFID—European Laboratory for Food Induced Diseases”, University of Salerno, 84084 Fisciano, SA, Italy
| | - Lucrezia Catapano
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy; (A.V.); (G.D.); (C.T.); (B.S.); (L.C.)
| | - Anna Marabotti
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano, SA, Italy; (A.V.); (G.D.); (C.T.); (B.S.); (L.C.)
- Interuniversity Center “ELFID—European Laboratory for Food Induced Diseases”, University of Salerno, 84084 Fisciano, SA, Italy
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3
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Verdino A, D’Urso G, Tammone C, Scafuri B, Marabotti A. Analysis of the Structure-Function-Dynamics Relationships of GALT Enzyme and of Its Pathogenic Mutant p.Q188R: A Molecular Dynamics Simulation Study in Different Experimental Conditions. Molecules 2021; 26:5941. [PMID: 34641485 PMCID: PMC8513031 DOI: 10.3390/molecules26195941] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/14/2021] [Accepted: 09/25/2021] [Indexed: 11/21/2022] Open
Abstract
The third step of the catabolism of galactose in mammals is catalyzed by the enzyme galactose-1-phosphate uridylyltransferase (GALT), a homodimeric enzyme with two active sites located in the proximity of the intersubunit interface. Mutations of this enzyme are associated to the rare inborn error of metabolism known as classic galactosemia; in particular, the most common mutation, associated with the most severe phenotype, is the one that replaces Gln188 in the active site of the enzyme with Arg (p.Gln188Arg). In the past, and more recently, the structural effects of this mutation were deduced on the static structure of the wild-type human enzyme; however, we feel that a dynamic view of the proteins is necessary to deeply understand their behavior and obtain tips for possible therapeutic interventions. Thus, we performed molecular dynamics simulations of both wild-type and p.Gln188Arg GALT proteins in the absence or in the presence of the substrates in different conditions of temperature. Our results suggest the importance of the intersubunit interactions for a correct activity of this enzyme and can be used as a starting point for the search of drugs able to rescue the activity of this enzyme in galactosemic patients.
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Affiliation(s)
- Anna Verdino
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy; (A.V.); (G.D.); (C.T.); (B.S.)
| | - Gaetano D’Urso
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy; (A.V.); (G.D.); (C.T.); (B.S.)
| | - Carmen Tammone
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy; (A.V.); (G.D.); (C.T.); (B.S.)
| | - Bernardina Scafuri
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy; (A.V.); (G.D.); (C.T.); (B.S.)
- Interuniversity Center, ELFID—European Laboratory for Food Induced Diseases, University of Salerno, 84084 Fisciano (SA), Italy
| | - Anna Marabotti
- Department of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II, 132, 84084 Fisciano (SA), Italy; (A.V.); (G.D.); (C.T.); (B.S.)
- Interuniversity Center, ELFID—European Laboratory for Food Induced Diseases, University of Salerno, 84084 Fisciano (SA), Italy
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4
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Banford S, McCorvie TJ, Pey AL, Timson DJ. Galactosemia: Towards Pharmacological Chaperones. J Pers Med 2021; 11:jpm11020106. [PMID: 33562227 PMCID: PMC7914515 DOI: 10.3390/jpm11020106] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 02/07/2023] Open
Abstract
Galactosemia is a rare inherited metabolic disease resulting from mutations in the four genes which encode enzymes involved in the metabolism of galactose. The current therapy, the removal of galactose from the diet, is inadequate. Consequently, many patients suffer lifelong physical and cognitive disability. The phenotype varies from almost asymptomatic to life-threatening disability. The fundamental biochemical cause of the disease is a decrease in enzymatic activity due to failure of the affected protein to fold and/or function correctly. Many novel therapies have been proposed for the treatment of galactosemia. Often, these are designed to treat the symptoms and not the fundamental cause. Pharmacological chaperones (PC) (small molecules which correct the folding of misfolded proteins) represent an exciting potential therapy for galactosemia. In theory, they would restore enzyme function, thus preventing downstream pathological consequences. In practice, no PCs have been identified for potential application in galactosemia. Here, we review the biochemical basis of the disease, identify opportunities for the application of PCs and describe how these might be discovered. We will conclude by considering some of the clinical issues which will affect the future use of PCs in the treatment of galactosemia.
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Affiliation(s)
- Samantha Banford
- South Eastern Health and Social Care Trust, Downpatrick BT30 6RL, UK;
| | - Thomas J. McCorvie
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK;
| | - Angel L. Pey
- Departamento de Química Física, Unidad de Excelencia de Química aplicada a Biomedicina y Medioambiente e Instituto de Biotecnología, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain;
| | - David J. Timson
- School of Pharmacy and Biomolecular Sciences, The University of Brighton, Brighton BN2 4GJ, UK
- Correspondence:
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5
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Marabotti A, Scafuri B, Facchiano A. Predicting the stability of mutant proteins by computational approaches: an overview. Brief Bioinform 2020; 22:5850907. [PMID: 32496523 DOI: 10.1093/bib/bbaa074] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/07/2020] [Accepted: 04/10/2020] [Indexed: 01/06/2023] Open
Abstract
A very large number of computational methods to predict the change in thermodynamic stability of proteins due to mutations have been developed during the last 30 years, and many different web servers are currently available. Nevertheless, most of them suffer from severe drawbacks that decrease their general reliability and, consequently, their applicability to different goals such as protein engineering or the predictions of the effects of mutations in genetic diseases. In this review, we have summarized all the main approaches used to develop these tools, with a survey of the web servers currently available. Moreover, we have also reviewed the different assessments made during the years, in order to allow the reader to check directly the different performances of these tools, to select the one that best fits his/her needs, and to help naïve users in finding the best option for their needs.
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6
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d'Acierno A, Scafuri B, Facchiano A, Marabotti A. The evolution of a Web resource: The Galactosemia Proteins Database 2.0. Hum Mutat 2017; 39:52-60. [DOI: 10.1002/humu.23346] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Antonio d'Acierno
- CNR-ISA; National Research Council; Institute of Food Science; Avellino Italy
| | - Bernardina Scafuri
- CNR-ISA; National Research Council; Institute of Food Science; Avellino Italy
| | - Angelo Facchiano
- CNR-ISA; National Research Council; Institute of Food Science; Avellino Italy
| | - Anna Marabotti
- Department of Chemistry and Biology “A. Zambelli”; University of Salerno; Fisciano SA Italy
- Interuniversity Center “ELFID-European Laboratory for Food Induced Diseases”; University of Salerno; Fisciano Italy
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7
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dAcierno A. IsAProteinDB: An Indexed Database of Trypsinized Proteins for Fast Peptide Mass Fingerprinting. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2017; 14:1195-1201. [PMID: 28113723 DOI: 10.1109/tcbb.2016.2564964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In peptite mass fingerprinting, an unknown protein is fragmented into smaller peptides whose masses are accurately measured; the obtained list of weights is then compared with a reference database to obtain a set of matching proteins. The exponential growth of known proteins discourage the use of brute force methods, where the weights' list is compared with each protein in the reference collection; luckily, the scientific literature in the database field highlights that well designed searching algorithms, coupled with a proper data organization, allow to quickly solve the identification problem even on standard desktop computers. In this paper, IsAProteinsDB, an indexed database of trypsinized proteins, is presented. The corresponding search algorithm shows a time complexity that does not significantly depends on the size of the reference protein database.
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8
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Viggiano E, Marabotti A, Politano L, Burlina A. Galactose-1-phosphate uridyltransferase deficiency: A literature review of the putative mechanisms of short and long-term complications and allelic variants. Clin Genet 2017; 93:206-215. [PMID: 28374897 DOI: 10.1111/cge.13030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/29/2017] [Accepted: 03/31/2017] [Indexed: 12/30/2022]
Abstract
Galactosemia type 1 is an autosomal recessive disorder of galactose metabolism, determined by a deficiency in the enzyme galactose-1-phosphate uridyltransferase (GALT). GALT deficiency is classified as severe or variant depending on biochemical phenotype, genotype and potential to develop acute and long-term complications. Neonatal symptoms usually resolve after galactose-restricted diet; however, some patients, despite the diet, can develop long-term complications, in particular when the GALT enzyme activity results absent or severely decreased. The mechanisms of acute and long-term complications are still discussed and several hypotheses are presented in the literature like enzymatic inhibition, osmotic stress, endoplasmic reticulum stress, oxidative stress, defects of glycosylation or epigenetic modification. This review summarizes the current knowledge of galactosemia, in particular the putative mechanisms of neonatal and long-term complications and the molecular genetics of GALT deficiency.
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Affiliation(s)
- E Viggiano
- Division of Metabolic Diseases, Department of Paediatrics, University Hospital of Padua, Padua, Italy.,Cardiomyology and Medical Genetics, Department of Experimental Medicine, Second University of Naples, Naples, Italy
| | - A Marabotti
- Department of Chemistry and Biology "A. Zambelli", University of Salerno, Salerno, Italy.,Interuniversity Center "ELFID", University of Salerno, Fisciano, Italy
| | - L Politano
- Cardiomyology and Medical Genetics, Department of Experimental Medicine, Second University of Naples, Naples, Italy
| | - A Burlina
- Division of Metabolic Diseases, Department of Paediatrics, University Hospital of Padua, Padua, Italy
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9
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Timson DJ. The molecular basis of galactosemia — Past, present and future. Gene 2016; 589:133-41. [DOI: 10.1016/j.gene.2015.06.077] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/18/2015] [Accepted: 06/29/2015] [Indexed: 12/19/2022]
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10
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Abstract
Galactokinase catalyses the first committed step of the Leloir pathway, i.e. the ATP-dependent phosphorylation of α-D-galactose at C1-OH. Reduced galactokinase activity results in the inherited metabolic disease type II galactosaemia. However, inhibition of galactokinase is considered a viable approach to treating more severe forms of galactosaemia (types I and III). Considerable progress has been made in the identification of high affinity, selective inhibitors. Although the structure of galactokinase from a variety of species is known, its catalytic mechanism remains uncertain. Although the bulk of evidence suggests that the reaction proceeds via an active site base mechanism, some experimental and theoretical studies contradict this. The enzyme has potential as a biocatalyst in the production of sugar 1-phosphates. This potential is limited by its high specificity. A variety of approaches have been taken to identify galactokinase variants which are more promiscuous. These have broadened galactokinase's specificity to include a wide range of D- and L-sugars. Initial studies suggest that some of these alterations result in increased flexibility at the active site. It is suggested that modulation of protein flexibility is at least as important as structural modifications in determining the success or failure of enzyme engineering.
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11
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Browne C, Timson DJ. In SilicoPrediction of the Effects of Mutations in the Human Mevalonate Kinase Gene: Towards a Predictive Framework for Mevalonate Kinase Deficiency. Ann Hum Genet 2015; 79:451-9. [DOI: 10.1111/ahg.12126] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/29/2015] [Accepted: 05/21/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Claire Browne
- School of Biological Sciences; Queen's University Belfast, Medical Biology Centre; 97 Lisburn Road Belfast BT9 7BL UK
| | - David J. Timson
- School of Biological Sciences; Queen's University Belfast, Medical Biology Centre; 97 Lisburn Road Belfast BT9 7BL UK
- Institute for Global Food Security; Queen's University Belfast; 18-30 Malone Road Belfast BT9 5BN UK
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12
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Timson DJ. Value of predictive bioinformatics in inherited metabolic diseases. World J Med Genet 2015; 5:46-51. [DOI: 10.5496/wjmg.v5.i3.46] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/28/2015] [Accepted: 05/18/2015] [Indexed: 02/06/2023] Open
Abstract
Typically, inherited metabolic diseases arise from point mutations in genes encoding metabolic enzymes. Although some of these mutations directly affect amino acid residues in the active sites of these enzymes, the majority do not. It is now well accepted that the majority of these disease-associated mutations exert their effects through alteration of protein stability, which causes a reduction in enzymatic activity. This finding suggests a way to predict the severity of newly discovered mutations. In silico prediction of the effects of amino acid sequence alterations on protein stability often correlates with disease severity. However, no stability prediction tool is perfect and, in general, better results are obtained if the predictions from a variety of tools are combined and then interpreted. In addition to predicted alterations to stability, the degree of conservation of a particular residue can also be a factor which needs to be taken into account: alterations to highly conserved residues are more likely to be associated with severe forms of the disease. The approach has been successfully applied in a variety of inherited metabolic diseases, but further improvements are necessary to enable robust translation into clinically useful tools.
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13
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Cocanougher B, Aypar U, McDonald A, Hasadsri L, Bennett MJ, Edward Highsmith W, D׳Aco K. Biochemical and computational analyses of two phenotypically related GALT mutations (S222N and S135L) that lead to atypical galactosemia. Data Brief 2015. [PMID: 26217714 PMCID: PMC4509990 DOI: 10.1016/j.dib.2015.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Galactosemia is a metabolic disorder caused by mutations in the GALT gene [1,2]. We encountered a patient heterozygous for a known pathogenic H132Q mutation and a novel S222N variant of unknown significance [3]. Reminiscent of patients with the S135L mutation, our patient had loss of GALT enzyme activity in erythrocytes but a very mild clinical phenotype [3–8]. We performed splicing experiments and computational structural analyses to investigate the role of the novel S222N variant. Alamut software data predicted loss of splicing enhancers for the S222N and S135L mutations [9,10]. A cDNA library was generated from our patient׳s RNA to investigate for splicing errors, but no change in transcript length was seen [3]. In silico structural analysis was performed to investigate enzyme stability and attempt to understand the mechanism of the atypical galactosemia phenotype. Stability results are publicly available in the GALT Protein Database 2.0 [11–14]. Animations were created to give the reader a dynamic view of the enzyme structure and mutation locations. Protein database files and python scripts are included for further investigation.
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Affiliation(s)
- Benjamin Cocanougher
- University of Rochester School of Medicine and Dentistry, Department of Pediatrics, Division of Genetics, Rochester, NY, USA
| | - Umut Aypar
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Amber McDonald
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Linda Hasadsri
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Michael J Bennett
- Metabolic Disease Laboratory, Children׳s Hospital of Philadelphia, USA ; Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - W Edward Highsmith
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Kristin D׳Aco
- University of Rochester School of Medicine and Dentistry, Department of Pediatrics, Division of Genetics, Rochester, NY, USA
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14
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Cocanougher B, Aypar U, McDonald A, Hasadsri L, Bennett MJ, Edward Highsmith W, D'Aco K. Compound heterozygosity with a novel S222N GALT mutation leads to atypical galactosemia with loss of GALT activity in erythrocytes but little evidence of clinical disease. Mol Genet Metab Rep 2015. [PMID: 28649529 PMCID: PMC5471153 DOI: 10.1016/j.ymgmr.2014.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Galactosemia is an inborn error of galactose metabolism caused by mutations in the GALT gene. Though early detection and galactose restriction prevent severe liver disease, affected individuals have persistently elevated biomarkers and often neuro-developmental symptoms. We present a teenage compound heterozygote for a known pathogenic mutation (H132Q) and a novel variant of unknown significance (S222N), with nearly absent erythrocyte GALT enzyme activity but normal biomarkers and only mild anxiety despite diet non-adherence. This case is similar to a previously reported S135L mutation. In this report we investigate the novel S222N variant and critically evaluate a clinically puzzling case.
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Affiliation(s)
- Benjamin Cocanougher
- University of Rochester School of Medicine and Dentistry, Department of Pediatrics, Division of Genetics, Rochester, NY, USA
| | - Umut Aypar
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Amber McDonald
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Linda Hasadsri
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Michael J Bennett
- Metabolic Disease Laboratory, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - W Edward Highsmith
- Molecular Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Kristin D'Aco
- University of Rochester School of Medicine and Dentistry, Department of Pediatrics, Division of Genetics, Rochester, NY, USA
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15
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Viggiano E, Marabotti A, Burlina AP, Cazzorla C, D'Apice MR, Giordano L, Fasan I, Novelli G, Facchiano A, Burlina AB. Clinical and molecular spectra in galactosemic patients from neonatal screening in northeastern Italy: structural and functional characterization of new variations in the galactose-1-phosphate uridyltransferase (GALT) gene. Gene 2015; 559:112-8. [PMID: 25592817 DOI: 10.1016/j.gene.2015.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/29/2014] [Accepted: 01/08/2015] [Indexed: 10/24/2022]
Abstract
Classical galactosemia is an autosomal recessive inborn error of metabolism due to mutations of the GALT gene leading to toxic accumulation of galactose and derived metabolites. With the benefit of early diagnosis by neonatal screening and early therapy, the acute presentation of classical galactosemia can be prevented. However, despite early diagnosis and treatment, the long term outcome for these patients is still unpredictable because they may go on to develop cognitive disability, speech problems, neurological and/or movement disorders and, in females, ovarian dysfunction. The objectives of the current study were to report our experience with a group of galactosemic patients identified through the neonatal screening programs in northeastern Italy during the last 30years. No neonatal deaths due to galactosemia complications occurred after the introduction of the neonatal screening program. However, despite the early diagnosis and dietary treatment, the patients with classical galactosemia showed one or more long-term complications. A total of 18 different variations in the GALT gene were found in the patient cohort: 12 missense, 2 frameshift, 1 nonsense, 1 deletion, 1 silent variation, and 1 intronic. Six (p.R33P, p.G83V, p.P244S, p.L267R, p.L267V, p.E271D) were new variations. The most common variation was p.Q188R (12 alleles, 31.5%), followed by p.K285N (6 alleles, 15.7%) and p.N314D (6 alleles, 15.7%). The other variations comprised 1 or 2 alleles. In the patients carrying a new mutation, the biochemical analysis of GALT activity in erythrocytes showed an activity of <1%. In silico analysis (SIFT, PolyPhen-2 and the computational analysis on the static protein structure) showed potentially damaging effects of the six new variations on the GALT protein, thus expanding the genetic spectrum of GALT variations in Italy. The study emphasizes the difficulty in establishing a genotype-phenotype correlation in classical galactosemia and underlines the importance of molecular diagnostic testing prior to making any treatment.
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Affiliation(s)
- E Viggiano
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Italy
| | - A Marabotti
- Department of Chemistry and Biology, University of Salerno, via Giovanni Paolo II 132, 84084 Fisciano, SA, Italy
| | - A P Burlina
- Neurological Unit, St. Bassiano Hospital, Bassano del Grappa, Consultant in Neurometabolic Hereditary Diseases at the University Hospital of Padova, Italy
| | - C Cazzorla
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Italy
| | - M R D'Apice
- Department of Biomedicine and Prevention, School of Medicine, University of Rome "Tor Vergata" and Fondazione PTV "Policlinico Tor Vergata", Rome, Italy
| | - L Giordano
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Italy
| | - I Fasan
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Italy
| | - G Novelli
- Department of Biomedicine and Prevention, School of Medicine, University of Rome "Tor Vergata" and Fondazione PTV "Policlinico Tor Vergata", Rome, Italy
| | - A Facchiano
- National Research Council, Institute of Food Science, via Roma 64, 83100 Avellino, Italy
| | - A B Burlina
- Division of Inborn Metabolic Diseases, Department of Paediatrics, University Hospital of Padova, Italy.
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