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Almenabawy N, Bahl S, Ostlund AL, Ghai-Jain S, Sosova I, Chan A, Mercimek-Andrews S. Clinical and biochemical phenotypes, genotypes, and long-term outcomes of individuals with galactosemia type I from a single metabolic genetics center in Alberta. Mol Genet Metab Rep 2024; 38:101055. [PMID: 38469090 PMCID: PMC10926219 DOI: 10.1016/j.ymgmr.2024.101055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 03/13/2024] Open
Abstract
Background Galactosemia type I is an autosomal recessive disorder of galactose metabolism due to galactose-1-phosphate uridyltransferase deficiency, encoded by GALT. To investigate the phenotypes, genotypes and long-term outcomes of galactosemia, we performed a retrospective cohort study in our center. Methods All individuals with galactosemia type I were included. We divided individuals into two groups to compare the outcomes of those treated symptomatically (SymX) and asymptomatically (AsymX). We reviewed electronic patient charts for clinical features, biochemical investigations, molecular genetic investigations, treatments, and outcomes. Results There were 25 individuals including classic (n = 17), clinical variant (n = 4), and biochemical variant (Duarte) galactosemia (n = 4). Twelve individuals were diagnosed symptomatically (SymX), and 9 individuals were diagnosed asymptomatically (AsymX). We did not include individuals with biochemical variant (Duarte) galactosemia into any of these groups. At the time of the diagnosis, conjugated hyperbilirubinemia was present in 83.3% of SymX group, whereas only 22% of AsymX group. SymX group had hepatomegaly (25%), failure to thrive (33.3%), cataract (16.7%) and sepsis (25%), whereas none of the individuals in the AsymX group had these clinical features. Fourteen variants in GALT were identified including pathogenic/likely pathogenic (n = 12), and likely benign/benign (n = 2) variants. The vast majority of individuals with classic and clinical variant galactosemia were treated with a galactose-lactose-free diet for life (n = 20/21). Intellectual disability was present in 54.5% of the SymX group, and in 37.5% of the AsymX group as a long-term outcome. Tremors were present 50% of the SymX group, and in 22% of the AsymX group as a long-term outcome. Although, intellectual disability and tremors seem to be less common in the AsymX group, there was no statistically significant difference between both groups. Primary ovarian insufficiency was present 50% of the SymX group, whereas in 20% of the AsymX group in post-pubertal females. We report a novel hypomorphic GALT variant (p.Ala303Ser) in one individual with clinical variant galactosemia. We also report an individual with clinical variant galactosemia with normal urine galactitol levels on a normal diet. Conclusion It seems that newborn screening and early administration of a galactose-lactose-free diet decreases the long-term galactosemia-associated complications but does not prevent them completely. It may be that not all individuals with clinical variant galactosemia may need a galactose-lactose-free diet. It is timely to find new therapeutic strategies that can reduce the frequency of late-onset complications in galactosemia.
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Affiliation(s)
- Nihal Almenabawy
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Shalini Bahl
- Princess Margaret Cancer Centre, 101 College Street, Toronto, ON M5G 1L7, Canada
- Department of Medical Biophysics, University of Toronto, 101 College Street, Toronto, ON M5G 1L7, Canada
| | - Alyssa-Lyn Ostlund
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Shailly Ghai-Jain
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Iveta Sosova
- Alberta Newborn Screening and Biochemical Genetics Laboratory, University of Alberta Hospital, Alberta Precision Laboratories, Edmonton, AB, Canada
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, AB, Canada
| | - Alicia Chan
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Saadet Mercimek-Andrews
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Alberta Health Services, AB, Canada
- Women's and Children's Research Institute, University of Alberta, Canada
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2
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Forte G, Buonadonna AL, Pantaleo A, Fasano C, Capodiferro D, Grossi V, Sanese P, Cariola F, De Marco K, Lepore Signorile M, Manghisi A, Guglielmi AF, Simonetti S, Laforgia N, Disciglio V, Simone C. Classic Galactosemia: Clinical and Computational Characterization of a Novel GALT Missense Variant (p.A303D) and a Literature Review. Int J Mol Sci 2023; 24:17388. [PMID: 38139222 PMCID: PMC10744227 DOI: 10.3390/ijms242417388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/30/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
Classic galactosemia is an autosomal recessive inherited liver disorder of carbohydrate metabolism caused by deficient activity of galactose-1-phosphate uridylyltransferase (GALT). While a galactose-restricted diet is lifesaving, most patients still develop long-term complications. In this study, we report on a two-week-old female patient who is a compound heterozygote for a known pathogenic variant (p.K285N) and a novel missense variant (p.A303D) in the GALT gene. Segregation analysis showed that the patient inherited the p.K285N pathogenic variant from her father and the p.A303D variant from her mother. A bioinformatics analysis to predict the impact of the p.A303D missense variant on the structure and stability of the GALT protein revealed that it may be pathogenic. Based on this finding, we performed a literature review of all GALT missense variants identified in homozygous and compound heterozygous galactosemia patients carrying the p.K285N pathogenic variant to explore their molecular effects on the clinical phenotype of the disease. Our analysis revealed that these missense variants are responsible for a wide range of molecular defects. This study expands the clinical and mutational spectrum in classic galactosemia and reinforces the importance of understanding the molecular consequences of genetic variants to incorporate genetic analysis into clinical care.
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Affiliation(s)
- Giovanna Forte
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Antonia Lucia Buonadonna
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Antonino Pantaleo
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Candida Fasano
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Donatella Capodiferro
- Section of Neonatology and Neonatal Intensive Care Unit, Department of Interdisciplinary Medicine, “Aldo Moro” University of Bari, 70121 Bari, Italy; (D.C.); (N.L.)
| | - Valentina Grossi
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Paola Sanese
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Filomena Cariola
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Katia De Marco
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Martina Lepore Signorile
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Andrea Manghisi
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Anna Filomena Guglielmi
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Simonetta Simonetti
- Clinical Pathology and Neonatal Screening, Azienda Ospedaliera Universitaria Policlinico-Giovanni XXIII, 70124 Bari, Italy;
| | - Nicola Laforgia
- Section of Neonatology and Neonatal Intensive Care Unit, Department of Interdisciplinary Medicine, “Aldo Moro” University of Bari, 70121 Bari, Italy; (D.C.); (N.L.)
| | - Vittoria Disciglio
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
| | - Cristiano Simone
- Medical Genetics, National Institute of Gastroenterology-IRCCS “Saverio de Bellis” Research Hospital, 70013 Castellana Grotte, Italy; (G.F.); (A.L.B.); (A.P.); (C.F.); (V.G.); (P.S.); (F.C.); (K.D.M.); (M.L.S.); (A.M.); (A.F.G.)
- Medical Genetics, Department of Precision and Regenerative Medicine and Jonic Area (DiMePRe-J), University of Bari Aldo Moro, 70124 Bari, Italy
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Ghorbani MJ, Moravej H, Amirhakimi A, Geramizadeh B, Kalani M, Fallahi F. A novel missense mutation (c.516A>T; p.Glu172Asp) in the GALT gene as a cause of classic galactosemia: A case report. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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An extensive computational approach to analyze and characterize the functional mutations in the galactose-1-phosphate uridyl transferase (GALT) protein responsible for classical galactosemia. Comput Biol Med 2019; 117:103583. [PMID: 32072977 DOI: 10.1016/j.compbiomed.2019.103583] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/12/2019] [Accepted: 12/12/2019] [Indexed: 02/07/2023]
Abstract
Type I galactosemia is a very rare autosomal recessive genetic metabolic disorder that occurs because of the mutations present in the galactose-1-phosphate uridyl transferase (GALT) gene, resulting in a deficiency of the GALT enzyme. The action of the GALT enzyme is to convert galactose-1-phosphate and uridine diphosphate glucose into glucose-1-phosphate (G1P) and uridine diphosphate-galactose, a crucial second step of the Leloir pathway. A missense mutation in the GALT enzyme leads to variable galactosemia's clinical presentations, ranging from mild to severe. Our study aimed to employ a comprehensive computational pipeline to analyze the most prevalent missense mutations (p.S135L, p.K285 N, p.Q188R, and p.N314D) responsible for galactosemia; these genes could serve as potential targets for chaperone therapy. We analyzed the four mutations through different computational analyses, including amino acid conservation, in silico pathogenicity and stability predictions, and macromolecular simulations (MMS) at 50 ns The stability and pathogenicity predictors showed that the p.Q188R and p.S135L mutants are the most pathogenic and destabilizing. In agreement with these results, MMS analysis demonstrated that the p.Q188R and p.S135L mutants possess higher deviation patterns, reduced compactness, and intramolecular H-bonds of the protein. This could be due to the physicochemical modifications that occurred in the mutants p.S135L and p.Q188R compared to the native. Evolutionary conservation analysis revealed that the most prevalent mutations positions were conserved among different species except N314. The proposed research study is intended to provide a basis for the therapeutic development of drugs and future treatment of classical galactosemia and possibly other genetic diseases using chaperone therapy.
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Yuzyuk T, Wilson AR, Mao R, Pasquali M. Galactose-1-Phosphate Uridyltransferase Activities in Different Genotypes: A Retrospective Analysis of 927 Samples. J Appl Lab Med 2019; 3:222-230. [DOI: 10.1373/jalm.2017.025536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 01/29/2018] [Indexed: 11/06/2022]
Abstract
Abstract
Background
Classic galactosemia is an inherited disorder of galactose metabolism caused by the impaired activity of galactose-1-phosphate uridyltransferase (GALT). Untreated galactosemia is life-threatening; however, early dietary intervention prevents mortality and reduces morbidity associated with this disease. The diagnosis of galactosemia includes the measurement of GALT activity in red blood cells (RBC) and GALT gene analysis. In this study, we evaluate GALT activity in different genotypes using the results of combined biochemical and molecular testing in 927 samples.
Methods
GALT activity in RBC was measured by LC-MS/MS. The analysis of the GALT gene was performed by targeted gene analysis and/or full gene sequencing. Samples were assigned based on the presence of pathogenic (G) or Duarte 2 (D) variants, or their absence (Neg), to G/G, D/G, G/Neg, D/D, D/Neg, and Neg/Neg genotypes. Finite mixture models were applied to investigate distributions of GALT activities in these genotypes. The reference ranges were determined using the central 95% of values of GALT activities.
Results
The ranges of GALT activity in G/G, D/G, G/Neg, D/D, D/Neg, and Neg/Neg genotypes are 0.0 to 0.7 μmol·h−1 gHb−1, 3.1 to 7.8 μmol·h−1 gHb−1, 6.5 to 16.2 μmol·h−1 gHb−1, 6.4 to 16.5 μmol·h−1 gHb−1, 12.0 to 24.0 μmol·h−1 gHb−1, and 19.4 to 33.4 μmol·h−1 gHb−1, respectively.
Conclusions
The GALT activity ranges established in this study are in agreement with the expected impact of the genotype on the enzymatic activity. Molecular findings should be interpreted in view of biochemical results to confirm genotype–phenotype correlation.
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Affiliation(s)
- Tatiana Yuzyuk
- Department of Pathology, University of Utah, Salt Lake City, UT
- ARUP Laboratories, Salt Lake City, UT
| | - Andrew R Wilson
- School of Nursing, University of Utah Health Sciences Center, Salt Lake City, UT
| | - Rong Mao
- Department of Pathology, University of Utah, Salt Lake City, UT
- ARUP Laboratories, Salt Lake City, UT
| | - Marzia Pasquali
- Department of Pathology, University of Utah, Salt Lake City, UT
- ARUP Laboratories, Salt Lake City, UT
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Ohlsson A, Hunt M, Wedell A, von Döbeln U. Heterogeneity of disease-causing variants in the Swedish galactosemia population: Identification of 16 novel GALT variants. J Inherit Metab Dis 2019; 42:1008-1018. [PMID: 31194895 DOI: 10.1002/jimd.12136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 06/10/2019] [Accepted: 06/11/2019] [Indexed: 11/11/2022]
Abstract
The aim was to determine disease-causing variants in the GALT gene which codes for the enzyme galactose-1-phosphate uridylyltransferase. Loss of activity of this enzyme causes classical galactosemia-a life threatening, treatable disorder, included in the Swedish newborn screening program since 1967. A total of 66 patients with the disease are known in Sweden and 56 index patients were investigated. An additional two patients with Duarte galactosemia were included. The disease-causing variants were identified in all patients. As reported from other countries only a few variants frequently recur in severe disease. The two variants p.(Gln188Arg) (c.563A>G) and p.(Met142Lys) (c.425T>A) are present in several index patients whereas the remaining are found in one to three patients each. The most common variant, p.(Gln188Arg), has an allele frequency of 51% in the cohort. A total of 16 novel variants were found among the 33 different variants in the cohort. Two of these are synonymous variants affecting splicing, demonstrating the importance of the evaluation of synonymous variants at the cDNA level. Concise sentence: Galactosemia is a rare disease in Sweden and the disease-causing variants are heterogenous including two synonymous variants.
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Affiliation(s)
- Annika Ohlsson
- Centre for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Mary Hunt
- The School of Biological and Health Sciences, Dublin Institute of Technology, Dublin, Ireland
| | - Anna Wedell
- Centre for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - Ulrika von Döbeln
- Centre for Inherited Metabolic Diseases (CMMS), Karolinska University Hospital, Stockholm, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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Teke Kisa P, Kose M, Unal O, Er E, Hismi BO, Bulbul FS, Kose E, Gunduz M, Canda E, Kucukcongar A, Arslan N. Clinical and molecular characteristics and time of diagnosis of patients with classical galactosemia in an unscreened population in Turkey. J Pediatr Endocrinol Metab 2019; 32:675-681. [PMID: 31194682 DOI: 10.1515/jpem-2018-0457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/30/2019] [Indexed: 12/23/2022]
Abstract
Classical galactosemia is an autosomal recessive inborn error of metabolism caused by biallelic pathogenic variants in the GALT gene. With the benefit of early diagnosis by newborn screening, the acute presentation of galactosemia can be prevented. In this study, we describe the clinical phenotypes, time of diagnosis and GALT genotypes of 76 galactosemia patients from Turkey, where the disease is not yet included in the newborn screening program. The median age at first symptom was 10 days (range 5-20), while the median age at diagnosis was 30 days (range 17-53). Nearly half of the patients (36 patients, 47.4%) were diagnosed later than age 1 month. Fifty-eight individuals were found to have 18 different pathogenic variants in their 116 mutant alleles. In our sample, Q188R variant has the highest frequency with 53%, the other half of the allele frequency of the patients showed 17 different genotypes. Despite presenting with typical clinical manifestations, classical galactosemia patients are diagnosed late in Turkey. Due to the geographical location of our country, different pathogenic GALT variants may be seen in Turkish patients. In the present study, a clear genotype-phenotype correlation could not be established in patients.
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Affiliation(s)
- Pelin Teke Kisa
- Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Melis Kose
- Division of Pediatric Metabolism and Nutrition, Dr. Behcet Uz Children's Training and Research Hospital, Izmir, Turkey
| | - Ozlem Unal
- Division of Pediatric Metabolism and Nutrition, Ankara Children's Training and Research Hospital, Ankara, Turkey
| | - Esra Er
- Division of Pediatric Metabolism and Nutrition, Ege University Faculty of Medicine, Izmir, Turkey
| | - Burcu Ozturk Hismi
- Division of Pediatric Metabolism and Nutrition, Tepecik Training and Research Hospital, Izmir, Turkey
| | - Fatma Selda Bulbul
- Division of Pediatric Metabolism and Nutrition, Kirikkale University, Kirikkale, Turkey
| | - Engin Kose
- Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Mehmet Gunduz
- Division of Pediatric Metabolism and Nutrition, Ankara Children's Training and Research Hospital, Ankara, Turkey
| | - Ebru Canda
- Division of Pediatric Metabolism and Nutrition, Ege University Faculty of Medicine, Izmir, Turkey
| | - Aynur Kucukcongar
- Division of Pediatric Metabolism and Nutrition, Ankara Children's Training and Research Hospital, Ankara, Turkey
| | - Nur Arslan
- Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
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Yuzyuk T, Balakrishnan B, Schwarz EL, De Biase I, Hobert J, Longo N, Mao R, Lai K, Pasquali M. Effect of genotype on galactose-1-phosphate in classic galactosemia patients. Mol Genet Metab 2018; 125:258-265. [PMID: 30172461 DOI: 10.1016/j.ymgme.2018.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 11/27/2022]
Abstract
Impaired activity of galactose-1-phosphate uridyltransferase (GALT) causes classic galactosemia (OMIM 230400), characterized by the accumulation of galactose-1-phosphate (GAL1P) in patients' red blood cells (RBCs). Our recent study demonstrated a correlation between RBC GAL1P and long-term outcomes in galactosemia patients. Here, we analyze biochemical and molecular results in 77 classic galactosemia patients to evaluate the association between GALT genotypes and GAL1P concentration in RBCs. Experimental data from model organisms were also included to assess the correlation between GAL1P and predicted residual activity of each genotype. Although all individuals in this study showed markedly reduced RBC GALT activity, we observed significant differences in RBC GAL1P concentrations among galactosemia genotypes. While levels of GAL1P on treatment did not correlate with RBC GALT activities (p = 0.166), there was a negative nonlinear correlation between mean GAL1P concentrations and predicted residual enzyme activity of genotype (p = 0.004). These studies suggest that GAL1P levels in RBCs on treatment likely reflect the overall functional impairment of GALT in patients with galactosemia.
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Affiliation(s)
- Tatiana Yuzyuk
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA.
| | - Bijina Balakrishnan
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, UT, USA
| | | | - Irene De Biase
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA
| | - Judith Hobert
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA
| | - Nicola Longo
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA; Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Rong Mao
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA
| | - Kent Lai
- Division of Medical Genetics/Pediatrics, University of Utah, Salt Lake City, UT, USA
| | - Marzia Pasquali
- Department of Pathology, University of Utah, Salt Lake City, UT, USA; ARUP Laboratories, Salt Lake City, UT, USA
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9
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Ramadža DP, Sarnavka V, Vuković J, Fumić K, Krželj V, Lozić B, Pušeljić S, Pereira H, Silva MJ, Tavares de Almeida I, Barić I, Rivera I. Molecular basis and clinical presentation of classic galactosemia in a Croatian population. J Pediatr Endocrinol Metab 2018; 31:71-75. [PMID: 29252199 DOI: 10.1515/jpem-2017-0302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/02/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Classic galactosemia is an autosomal recessive disorder of galactose metabolism caused by severely decreased activity of galactose-1-phosphate uridylyltransferase (GALT) due to pathogenic mutations in the GALT gene. To date more than 330 mutations have been described, with p.Q188R and p.K285N being the most common in Caucasian populations. Although acute manifestations can be fully avoided by a galactose-restricted diet, chronic complications, such as neurological ones, cannot be prevented in a significant number of patients despite compliance with the dietary treatment. METHODS A cohort of 16 galactosemic Croatian patients, including one pair of siblings, was studied. Molecular characterization was performed by direct sequence analysis of the GALT gene. RESULTS Sixteen patients were analyzed and only four different mutations were detected. As expected, p.Q188R and p.K285N were common, accounting for 40% and 37% of unrelated alleles, respectively. The third mutation accounting for 20% of mutant alleles was p.R123X causing a premature stop codon, is thus considered to be severe, which is in accordance with the phenotype presented by the homozygous patient described here. The fourth mutation p.E271D was found in a single allele. More than half of our patients manifested some chronic neurological complications. CONCLUSIONS This is the first report on mutational and phenotypic spectra of classic galactosemia in Croatia that expands the knowledge on the mutational map of the GALT gene across Europe and reveals the genetic homogeneity of the Croatian population.
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Affiliation(s)
- Danijela Petković Ramadža
- Department of Pediatrics, University Hospital Centre, Zagreb, Croatia.,School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Vladimir Sarnavka
- Department of Pediatrics, University Hospital Centre, Zagreb, Croatia
| | - Jurica Vuković
- Department of Pediatrics, University Hospital Centre, Zagreb, Croatia.,School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Ksenija Fumić
- Department of Laboratory Diagnostics, University Hospital Centre, Zagreb, Croatia
| | - Vjekoslav Krželj
- Department of Pediatrics, University Hospital Centre, Split, Croatia
| | - Bernarda Lozić
- Department of Pediatrics, University Hospital Centre, Split, Croatia
| | - Silvija Pušeljić
- Department of Pediatrics, University Hospital Centre, Osijek, Croatia
| | - Hana Pereira
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
| | - Maria João Silva
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.,Department of Biochemistry and Human Biology, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
| | - Isabel Tavares de Almeida
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
| | - Ivo Barić
- Department of Pediatrics, University Hospital Centre, Zagreb, Croatia.,School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Isabel Rivera
- Metabolism and Genetics Group, Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal.,Department of Biochemistry and Human Biology, Faculty of Pharmacy, University of Lisbon, Lisbon, Portugal
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10
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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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11
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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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12
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De Lucca M, Barba C, Casique L. A novel splicing mutation in GALT gene causing Galactosemia in Ecuadorian family. Clin Chim Acta 2017; 470:20-23. [PMID: 28450132 DOI: 10.1016/j.cca.2017.04.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 12/11/2022]
Abstract
Classic Galactosemia (OMIM 230400) is an autosomal recessive disorder of galactose metabolism caused by mutations in the galactose-1-phosphate uridyl transferase (GALT) gene. This disease caused by the inability to metabolize galactose is potentially life-threatening but its pathophysiology has not been clearly defined. GALT gene presents high allelic heterogeneity and around 336 variations have been identified. Here, we report the case of a patient with Classic Galactosemia who was detected during a neonatal screening in Ecuador. Molecular study revealed a mutation in GALT gene intron 1, c.82+3A>G in homozygous condition, this mutation has not been previously reported. This gene variation was not found in any of the 119 healthy Ecuadorian individuals used as control. Furthermore, the mutation was the only alteration detected in the propositus's GALT after sequencing all exons and introns of this gene. In silico modeling predicted that the mutation was pathogenic.
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Affiliation(s)
- M De Lucca
- Laboratorio de Biología Molecular y Celular, Universidad Técnica de Ambato, Ambato, Ecuador.
| | - C Barba
- Laboratorio de Biología Molecular y Celular, Universidad Técnica de Ambato, Ambato, Ecuador
| | - L Casique
- Departamento de Biología Celular, Universidad Simón Bolívar, Caracas, Venezuela
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13
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Varela-Lema L, Paz-Valinas L, Atienza-Merino G, Zubizarreta-Alberdi R, Villares RV, López-García M. Appropriateness of newborn screening for classic galactosaemia: a systematic review. J Inherit Metab Dis 2016; 39:633-649. [PMID: 27116003 DOI: 10.1007/s10545-016-9936-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/28/2016] [Accepted: 04/06/2016] [Indexed: 12/11/2022]
Abstract
Currently, there is no universal agreement on galactosaemia screening, fundamentally because of the risk-benefit uncertainties. We conducted two exhaustive systematic searches in the main electronic databases (PubMed, Embase, Cochrane, etc.) to recover relevant information about the disease and screening test/s in order to support decision making in Spain. All of the 45 studies identified that covered disease issues were retrospective case series or cross-sectional analysis (level-4 evidence). Studies consistently found that the majority of patients presented characteristic symptomatology before diagnosis. Long term disabilities were not significantly correlated with age of diagnosis, onset of dietary restriction or strict diet compliance. The five studies that provided accuracy data used different cut-off points and verification tests, and thus differed in their definitions of a positive case (level-3b evidence). The estimated sensitivity was 100 % and the specificity 99.9 %. The false-positive rate ranged from 0.0005 % to 0.25 %, and the PPV from 0 % to 64.3 %. The comparative clinical effectiveness in relation to not screening or implementation of other programs is unknown. In summary, existing evidence remains insufficient to establish the appropriateness of newborn screening for galactosaemia screening, although health benefits could be expected if early diagnosis and treatment is achieved. If screening is implemented in Spain, it would be important that a pilot programme be implemented to assess false positive rate and ensure that early diagnosis is not delayed.
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Affiliation(s)
- L Varela-Lema
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain.
| | - L Paz-Valinas
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain
| | - G Atienza-Merino
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain
| | - R Zubizarreta-Alberdi
- Department of Innovation and Public Health, Galician Health Authority, Santiago de Compostela, Spain
| | - R Vizoso Villares
- Department of Innovation and Public Health, Galician Health Authority, Santiago de Compostela, Spain
| | - M López-García
- Scientific-Technical Advice Unit (avalia-t), Galician Agency for Health Knowledge Management, ACIS, Santiago de Compostela, Spain
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14
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McCorvie TJ, Kopec J, Pey AL, Fitzpatrick F, Patel D, Chalk R, Shrestha L, Yue WW. Molecular basis of classic galactosemia from the structure of human galactose 1-phosphate uridylyltransferase. Hum Mol Genet 2016; 25:2234-2244. [PMID: 27005423 PMCID: PMC5081055 DOI: 10.1093/hmg/ddw091] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 03/14/2016] [Indexed: 01/22/2023] Open
Abstract
Classic galactosemia is a potentially lethal disease caused by the dysfunction of galactose 1-phosphate uridylyltransferase (GALT). Over 300 disease-associated GALT mutations have been reported, with the majority being missense changes, although a better understanding of their underlying molecular effects has been hindered by the lack of structural information for the human enzyme. Here, we present the 1.9 Å resolution crystal structure of human GALT (hGALT) ternary complex, revealing a homodimer arrangement that contains a covalent uridylylated intermediate and glucose-1-phosphate in the active site, as well as a structural zinc-binding site, per monomer. hGALT reveals significant structural differences from bacterial GALT homologues in metal ligation and dimer interactions, and therefore is a zbetter model for understanding the molecular consequences of disease mutations. Both uridylylation and zinc binding influence the stability and aggregation tendency of hGALT. This has implications for disease-associated variants where p.Gln188Arg, the most commonly detected, increases the rate of aggregation in the absence of zinc likely due to its reduced ability to form the uridylylated intermediate. As such our structure serves as a template in the future design of pharmacological chaperone therapies and opens new concepts about the roles of metal binding and activity in protein misfolding by disease-associated mutants.
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Affiliation(s)
- Thomas J McCorvie
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ , UK
| | - Jolanta Kopec
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ , UK
| | - Angel L Pey
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Granada E-18071, Spain
| | - Fiona Fitzpatrick
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ , UK
| | - Dipali Patel
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ , UK
| | - Rod Chalk
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ , UK
| | - Leela Shrestha
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ , UK
| | - Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX3 7DQ , UK
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15
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Yavarna T, Al-Dewik N, Al-Mureikhi M, Ali R, Al-Mesaifri F, Mahmoud L, Shahbeck N, Lakhani S, AlMulla M, Nawaz Z, Vitazka P, Alkuraya FS, Ben-Omran T. High diagnostic yield of clinical exome sequencing in Middle Eastern patients with Mendelian disorders. Hum Genet 2015; 134:967-80. [PMID: 26077850 DOI: 10.1007/s00439-015-1575-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 05/30/2015] [Indexed: 12/16/2022]
Abstract
Clinical exome sequencing (CES) has become an increasingly popular diagnostic tool in patients with heterogeneous genetic disorders, especially in those with neurocognitive phenotypes. Utility of CES in consanguineous populations has not yet been determined on a large scale. A clinical cohort of 149 probands from Qatar with suspected Mendelian, mainly neurocognitive phenotypes, underwent CES from July 2012 to June 2014. Intellectual disability and global developmental delay were the most common clinical presentations but our cohort displayed other phenotypes, such as epilepsy, dysmorphism, microcephaly and other structural brain anomalies and autism. A pathogenic or likely pathogenic mutation, including pathogenic CNVs, was identified in 89 probands for a diagnostic yield of 60%. Consanguinity and positive family history predicted a higher diagnostic yield. In 5% (7/149) of cases, CES implicated novel candidate disease genes (MANF, GJA9, GLG1, COL15A1, SLC35F5, MAGE4, NEUROG1). CES uncovered two coexisting genetic disorders in 4% (6/149) and actionable incidental findings in 2% (3/149) of cases. Average time to diagnosis was reduced from 27 to 5 months. CES, which already has the highest diagnostic yield among all available diagnostic tools in the setting of Mendelian disorders, appears to be particularly helpful diagnostically in the highly consanguineous Middle Eastern population.
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Affiliation(s)
- Tarunashree Yavarna
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, P.O.BOX. 3050, Doha, Qatar
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16
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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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17
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Lacombe C, Untereiner V, Gobinet C, Zater M, Sockalingum GD, Garnotel R. Rapid screening of classic galactosemia patients: a proof-of-concept study using high-throughput FTIR analysis of plasma. Analyst 2015; 140:2280-6. [DOI: 10.1039/c4an01942c] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
FTIR as a new approach to screen a rare disease.
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Affiliation(s)
- Caroline Lacombe
- Université de Reims Champagne-Ardenne
- Equipe MéDIAN
- Biophotonique et Technologies pour la Santé
- UFR de Pharmacie
- 51096 Reims
| | - Valérie Untereiner
- Université de Reims Champagne-Ardenne
- Equipe MéDIAN
- Biophotonique et Technologies pour la Santé
- UFR de Pharmacie
- 51096 Reims
| | - Cyril Gobinet
- Université de Reims Champagne-Ardenne
- Equipe MéDIAN
- Biophotonique et Technologies pour la Santé
- UFR de Pharmacie
- 51096 Reims
| | - Mokhtar Zater
- Biochimie – Hôpital de Bicêtre
- Hôpitaux Universitaires Paris-Sud
- France
| | - Ganesh D. Sockalingum
- Université de Reims Champagne-Ardenne
- Equipe MéDIAN
- Biophotonique et Technologies pour la Santé
- UFR de Pharmacie
- 51096 Reims
| | - Roselyne Garnotel
- Université de Reims Champagne-Ardenne
- Equipe MéDIAN
- Biophotonique et Technologies pour la Santé
- UFR de Pharmacie
- 51096 Reims
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18
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d'Acierno A, Facchiano A, Marabotti A. GALT protein database: querying structural and functional features of GALT enzyme. Hum Mutat 2014; 35:1060-7. [PMID: 24990533 DOI: 10.1002/humu.22613] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 06/24/2014] [Indexed: 01/19/2023]
Abstract
Knowledge of the impact of variations on protein structure can enhance the comprehension of the mechanisms of genetic diseases related to that protein. Here, we present a new version of GALT Protein Database, a Web-accessible data repository for the storage and interrogation of structural effects of variations of the enzyme galactose-1-phosphate uridylyltransferase (GALT), the impairment of which leads to classic Galactosemia, a rare genetic disease. This new version of this database now contains the models of 201 missense variants of GALT enzyme, including heterozygous variants, and it allows users not only to retrieve information about the missense variations affecting this protein, but also to investigate their impact on substrate binding, intersubunit interactions, stability, and other structural features. In addition, it allows the interactive visualization of the models of variants collected into the database. We have developed additional tools to improve the use of the database by nonspecialized users. This Web-accessible database (http://bioinformatica.isa.cnr.it/GALT/GALT2.0) represents a model of tools potentially suitable for application to other proteins that are involved in human pathologies and that are subjected to genetic variations.
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19
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Tran TTV, Liu Y, Zwick ME, Ramachandran D, Cutler DJ, Huang X, Berry GT, Fridovich-Keil JL. A De Novo Variant in Galactose-1-P Uridylyltransferase (GALT) Leading to Classic Galactosemia. JIMD Rep 2014; 19:1-6. [DOI: 10.1007/8904_2014_349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Revised: 07/27/2014] [Accepted: 07/31/2014] [Indexed: 11/28/2022] Open
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20
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Galactosemia in the Turkish population with a high frequency of Q188R mutation and distribution of Duarte-1 and Duarte-2 variations. J Hum Genet 2013; 58:675-8. [DOI: 10.1038/jhg.2013.76] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/04/2013] [Accepted: 07/01/2013] [Indexed: 11/08/2022]
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21
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McCorvie TJ, Gleason TJ, Fridovich-Keil JL, Timson DJ. Misfolding of galactose 1-phosphate uridylyltransferase can result in type I galactosemia. Biochim Biophys Acta Mol Basis Dis 2013; 1832:1279-93. [PMID: 23583749 DOI: 10.1016/j.bbadis.2013.04.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/27/2013] [Accepted: 04/02/2013] [Indexed: 11/17/2022]
Abstract
Type I galactosemia is a genetic disorder that is caused by the impairment of galactose-1-phosphate uridylyltransferase (GALT; EC 2.7.7.12). Although a large number of mutations have been detected through genetic screening of the human GALT (hGALT) locus, for many it is not known how they cause their effects. The majority of these mutations are missense, with predicted substitutions scattered throughout the enzyme structure and thus causing impairment by other means rather than direct alterations to the active site. To clarify the fundamental, molecular basis of hGALT impairment we studied five disease-associated variants p.D28Y, p.L74P, p.F171S, p.F194L and p.R333G using both a yeast model and purified, recombinant proteins. In a yeast expression system there was a correlation between lysate activity and the ability to rescue growth in the presence of galactose, except for p.R333G. Kinetic analysis of the purified proteins quantified each variant's level of enzymatic impairment and demonstrated that this was largely due to altered substrate binding. Increased surface hydrophobicity, altered thermal stability and changes in proteolytic sensitivity were also detected. Our results demonstrate that hGALT requires a level of flexibility to function optimally and that altered folding is the underlying reason of impairment in all the variants tested here. This indicates that misfolding is a common, molecular basis of hGALT deficiency and suggests the potential of pharmacological chaperones and proteostasis regulators as novel therapeutic approaches for type I galactosemia.
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Affiliation(s)
- Thomas J McCorvie
- School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
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