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Mansouri‐Movahed F, Akhoundi F, Nikpour P, Garshasbi M, Emadi‐Baygi M. Identification of a novel HEXB Mutation in an Iranian Family with suspected patient to GM2-gangliosidoses. Clin Case Rep 2020; 8:2583-2591. [PMID: 33363784 PMCID: PMC7752470 DOI: 10.1002/ccr3.3103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/10/2020] [Accepted: 06/26/2020] [Indexed: 11/19/2022] Open
Abstract
Sandhoff disease is one of the GM2-gangliosidoses which is caused by a mutation in the HEXB preventing the breakdown of GM2-ganglioside. We report a novel HEXB variant in a family with a history of a dead girl with Sandhoff disease which was not found in controls.
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Affiliation(s)
| | - Fatemeh Akhoundi
- Department of GeneticsFaculty of Basic SciencesShahrekord UniversityShahrekordIran
| | - Parvaneh Nikpour
- Department of Genetics and Molecular BiologyFaculty of MedicineIsfahan University of Medical SciencesIsfahanIran
- Child Growth and Development Research CenterResearch Institute for Primordial Prevention of Non‐Communicable DiseaseIsfahan University of Medical SciencesIsfahanIran
| | - Masoud Garshasbi
- Department of Medical GeneticsFaculty of Medical SciencesTarbiat Modares UniversityTehranIran
| | - Modjtaba Emadi‐Baygi
- Department of GeneticsFaculty of Basic SciencesShahrekord UniversityShahrekordIran
- Research Institute of BiotechnologyShahrekord UniversityShahrekordIran
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Lee H, Choi J, Jeong E, Baek S, Kim HC, Chae JH, Koh Y, Seo SW, Kim JS, Kim SJ. dCas9-mediated Nanoelectrokinetic Direct Detection of Target Gene for Liquid Biopsy. NANO LETTERS 2018; 18:7642-7650. [PMID: 30421614 DOI: 10.1021/acs.nanolett.8b03224] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The-state-of-the-art bio- and nanotechnology have opened up an avenue to noninvasive liquid biopsy for identifying diseases from biomolecules in bloodstream, especially DNA. In this work, we combined sequence-specific-labeling scheme using mutated clustered regularly interspaced short palindromic repeats associated protein 9 without endonuclease activity (CRISPR/dCas9) and ion concentration polarization (ICP) phenomenon as a mechanism to selectively preconcentrate targeted DNA molecules for rapid and direct detection. Theoretical analysis on ICP phenomenon figured out a critical mobility, elucidating two distinguishable concentrating behaviors near a nanojunction, a stacking and a propagating behavior. Through the modulation of the critical mobility to shift those behaviors, the C-C chemokine receptor type 5 ( CCR5) sequences were optically detected without PCR amplification. Conclusively, the proposed dCas9-mediated genetic detection methodology based on ICP would provide rapid and accurate micro/nanofluidic platform of liquid biopsies for disease diagnostics.
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Affiliation(s)
- Hyomin Lee
- Department of Chemical and Biological Engineering , Jeju National University , Jeju , 63243 , Republic of Korea
| | | | - Euihwan Jeong
- Center for Genome Engineering , Institute for Basic Science , Seoul 34047 , Republic of Korea
| | | | | | | | - Youngil Koh
- Department of Internal Medicine , Seoul National University Hospital , Seoul 03080 , Republic of Korea
| | | | - Jin-Soo Kim
- Center for Genome Engineering , Institute for Basic Science , Seoul 34047 , Republic of Korea
| | - Sung Jae Kim
- Inter-university Semiconductor Research Center , Seoul National University , Seoul 08826 , Republic of Korea
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Mahdieh N, Mikaeeli S, Tavasoli AR, Rezaei Z, Maleki M, Rabbani B. Genotype, phenotype and in silico pathogenicity analysis of HEXB mutations: Panel based sequencing for differential diagnosis of gangliosidosis. Clin Neurol Neurosurg 2018; 167:43-53. [PMID: 29448188 DOI: 10.1016/j.clineuro.2018.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 01/31/2018] [Accepted: 02/05/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVES Gangliosidosis is an inherited metabolic disorder causing neurodegeneration and motor regression. Preventive diagnosis is the first choice for the affected families due to lack of straightforward therapy. Genetic studies could confirm the diagnosis and help families for carrier screening and prenatal diagnosis. An update of HEXB gene variants concerning genotype, phenotype and in silico analysis are presented. PATIENTS AND METHODS Panel based next generation sequencing and direct sequencing of four cases were performed to confirm the clinical diagnosis and for reproductive planning. Bioinformatic analyses of the HEXB mutation database were also performed. RESULTS Direct sequencing of HEXA and HEXB genes showed recurrent homozygous variants at c.509G>A (p.Arg170Gln) and c.850C>T (p.Arg284Ter), respectively. A novel variant at c.416T>A (p.Leu139Gln) was identified in the GLB1 gene. Panel based next generation sequencing was performed for an undiagnosed patient which showed a novel mutation at c.1602C>A (p.Cys534Ter) of HEXB gene. Bioinformatic analysis of the HEXB mutation database showed 97% consistency of in silico genotype analysis with the phenotype. Bioinformatic analysis of the novel variants predicted to be disease causing. In silico structural and functional analysis of the novel variants showed structural effect of HEXB and functional effect of GLB1 variants which would provide fast analysis of novel variants. CONCLUSIONS Panel based studies could be performed for overlapping symptomatic patients. Consequently, genetic testing would help affected families for patients' management, carrier detection, and family planning's.
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Affiliation(s)
- Nejat Mahdieh
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Sahar Mikaeeli
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Tavasoli
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran; Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Rezaei
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Majid Maleki
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Bahareh Rabbani
- Genetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran.
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4
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Masri A, Liao J, Kornreich R, Haghighi A. Homozygous p.R284* mutation in HEXB gene causing Sandhoff disease with nystagmus. Eur J Paediatr Neurol 2014; 18:399-403. [PMID: 24613245 DOI: 10.1016/j.ejpn.2014.02.002] [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: 11/01/2013] [Revised: 01/21/2014] [Accepted: 02/07/2014] [Indexed: 01/30/2023]
Abstract
Sandhoff disease is a rare, genetic, lipid storage disorder characterized by progressive degeneration of the nerve cells (neurons) in the brain and spinal cord. This disease is caused by mutations in the beta-hexosaminidase beta-subunit (HEXB) gene. Here, we investigated the clinical characteristics and molecular basis of Sandhoff disease in an infant female patient from Jordan. The initial sign was nystagmus, which was noted at birth. To our knowledge, this is the first report of Sandhoff disease from Jordan. Introducing lysosomal enzyme assays to the testing of children with global developmental delay with unknown etiology in countries with high rates of consanguinity will not only increase the percentage of diagnosed cases, but will also help orient genetic counseling and prenatal diagnosis and eventually will reduce the overall burden of disabilities in these countries.
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Affiliation(s)
- Amira Masri
- Division of Child Neurology, Department of Pediatrics, Faculty of Medicine, The University of Jordan, Amman, Jordan
| | - Jun Liao
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ruth Kornreich
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alireza Haghighi
- Department of Genetics, Harvard Medical School, Boston, MA, USA; Department of Medicine and the Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA, USA.
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5
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Gort L, de Olano N, Macías-Vidal J, Coll MJ. GM2 gangliosidoses in Spain: Analysis of the HEXA and HEXB genes in 34 Tay–Sachs and 14 Sandhoff patients. Gene 2012; 506:25-30. [DOI: 10.1016/j.gene.2012.06.080] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/21/2012] [Accepted: 06/25/2012] [Indexed: 10/28/2022]
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Sobek AKU, Evers C, Dekomien G. Integrated multiplex ligation dependent probe amplification (MLPA) assays for the detection of alterations in the HEXB, GM2A and SMARCAL1 genes to support the diagnosis of Morbus Sandhoff, M. Tay-Sachs variant AB and Schimke immuno-osseous dysplasia in humans. Mol Cell Probes 2012; 27:32-7. [PMID: 23010210 DOI: 10.1016/j.mcp.2012.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 08/13/2012] [Accepted: 08/14/2012] [Indexed: 10/27/2022]
Abstract
Multiplex ligation dependent probe amplification (MLPA) assays were designed for the genes HEXB (OMIM: 606873), GM2A (OMIM: 613109) and SMARCAL1 (OMIM: 606622) of humans. Two sets of synthetic MLPA probes for these coding exons were tested. Changes in copy numbers were detected as well as single nucleotide polymorphisms (SNPs) by complementary DNA sequence analyses. The MLPA method was shown to be reliable for mutation detection and identified five published and 12 new mutations. In all cases from a Morbus Sandhoff cohort of patients, exclusively one variation in copy number was observed and linked to a nucleotide alteration called c.1614-14C>A. This deletion comprised exons 1-5. One of these cases is described in detail. Deletions were neither detected in the GM2A nor the SMARCAL1 genes. The MLPA assays complement routine diagnostics for M. Sandhoff (OMIM: 268800), M. Tay-Sachs variant AB (OMIM: 272750) and Schimke immuno-osseous dysplasia (OMIM: 242900).
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Affiliation(s)
- Anna K U Sobek
- Human Genetics, Ruhr University Bochum, Universitaetsstrasse 150, 44801 Bochum, Germany
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Zampieri S, Cattarossi S, Oller Ramirez AM, Rosano C, Lourenco CM, Passon N, Moroni I, Uziel G, Pettinari A, Stanzial F, de Kremer RD, Azar NB, Hazan F, Filocamo M, Bembi B, Dardis A. Sequence and copy number analyses of HEXB gene in patients affected by Sandhoff disease: functional characterization of 9 novel sequence variants. PLoS One 2012; 7:e41516. [PMID: 22848519 PMCID: PMC3407239 DOI: 10.1371/journal.pone.0041516] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Accepted: 06/21/2012] [Indexed: 11/18/2022] Open
Abstract
Sandhoff disease (SD) is a lysosomal disorder caused by mutations in the HEXB gene. To date, 43 mutations of HEXB have been described, including 3 large deletions. Here, we have characterized 14 unrelated SD patients and developed a Multiplex Ligation-dependent Probe Amplification (MLPA) assay to investigate the presence of large HEXB deletions. Overall, we identified 16 alleles, 9 of which were novel, including 4 sequence variation leading to aminoacid changes [c.626C>T (p.T209I), c.634C>A (p.H212N), c.926G>T (p.C309F), c.1451G>A (p.G484E)] 3 intronic mutations (c.1082+5G>A, c.1242+1G>A, c.1169+5G>A), 1 nonsense mutation c.146C>A (p.S49X) and 1 small in-frame deletion c.1260_1265delAGTTGA (p.V421_E422del). Using the new MLPA assay, 2 previously described deletions were identified. In vitro expression studies showed that proteins bearing aminoacid changes p.T209I and p.G484E presented a very low or absent activity, while proteins bearing the p.H212N and p.C309F changes retained a significant residual activity. The detrimental effect of the 3 novel intronic mutations on the HEXB mRNA processing was demonstrated using a minigene assay. Unprecedentedly, minigene studies revealed the presence of a novel alternative spliced HEXB mRNA variant also present in normal cells. In conclusion, we provided new insights into the molecular basis of SD and validated an MLPA assay for detecting large HEXB deletions.
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Affiliation(s)
- Stefania Zampieri
- Regional Coordinator Center for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
| | - Silvia Cattarossi
- Regional Coordinator Center for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
| | - Ana Maria Oller Ramirez
- Centro de Estudio de las Metabolopatias Congénitas, CEMECO, University of Córdoba, Córdoba, Argentine
| | - Camillo Rosano
- Patologia Molecolare Integrata – A.O.U. IRCSS San Martino – IST, Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy
| | - Charles Marques Lourenco
- Medical Genetics Service, Clinics Hospital of Ribeirao Preto, University of Sao Paulo, Sao Paulo, Brazil
| | - Nadia Passon
- Dipartimento di Scienze Mediche e Biologiche, Università di Udine, Udine, Italy
| | - Isabella Moroni
- Department of Child Neurology, Fondazione Istituto Neurologico Besta, Milan, Italy
| | - Graziella Uziel
- Department of Child Neurology, Fondazione Istituto Neurologico Besta, Milan, Italy
| | - Antonella Pettinari
- Laboratorio di Genetica Medica, Clinica Pediatrica, Ospedali Riuniti Ancona, Ancona, Italy
| | - Franco Stanzial
- Servizio di Consulenza Genetica, Centro Provinciale di Coordinamento della Rete delle Malattie Rare, Azienda Sanitaria dell’Alto-Adige, Bolzano, Italy
| | - Raquel Dodelson de Kremer
- Centro de Estudio de las Metabolopatias Congénitas, CEMECO, University of Córdoba, Córdoba, Argentine
| | - Nydia Beatriz Azar
- Centro de Estudio de las Metabolopatias Congénitas, CEMECO, University of Córdoba, Córdoba, Argentine
| | - Filiz Hazan
- Medical Faculty, Genetic Department, Izmir, Turkey
| | - Mirella Filocamo
- U.O.S.D. Laboratorio Diagnosi Pre-Postnatale Malattie Metaboliche, Istituto G. Gaslini, Genova, Italy
| | - Bruno Bembi
- Regional Coordinator Center for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
| | - Andrea Dardis
- Regional Coordinator Center for Rare Diseases, University Hospital Santa Maria della Misericordia, Udine, Italy
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Maegawa GHB, Stockley T, Tropak M, Banwell B, Blaser S, Kok F, Giugliani R, Mahuran D, Clarke JTR. The natural history of juvenile or subacute GM2 gangliosidosis: 21 new cases and literature review of 134 previously reported. Pediatrics 2006; 118:e1550-62. [PMID: 17015493 PMCID: PMC2910078 DOI: 10.1542/peds.2006-0588] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Juvenile GM2 gangliosidosis is a group of inherited neurodegenerative diseases caused by deficiency of lysosomal beta-hexosaminidase resulting in GM2 ganglioside accumulation in brain. The purpose of this study was to delineate the natural history of the condition and identify genotype-phenotype correlations that might be helpful in predicting the course of the disease in individual patients. METHODS A cohort of 21 patients with juvenile GM2 gangliosidosis, 15 with the Tay-Sachs variant and 6 with the Sandhoff variant, was studied prospectively in 2 centers. Our experience was compared with previously published reports on 134 patients. Information about clinical features, beta-hexosaminidase enzyme activity, and mutation analysis was collected. RESULTS In our cohort of patients, the mean (+/-SD) age of onset of symptoms was 5.3 +/- 4.1 years, with a mean follow-up time of 8.4 years. The most common symptoms at onset were gait disturbances (66.7%), incoordination (52.4%), speech problems (28.6%), and developmental delay (28.6%). The age of onset of gait disturbances was 7.1 +/- 5.6 years. The mean time for progression to becoming wheelchair-bound was 6.2 +/- 5.5 years. The mean age of onset of speech problems was 7.0 +/- 5.6 years, with a mean time of progression to anarthria of 5.6 +/- 5.3 years. Muscle wasting (10.6 +/- 7.4 years), proximal weakness (11.1 +/- 7.7 years), and incontinence of sphincters (14.6 +/- 9.7 years) appeared later in the course of the disease. Psychiatric disturbances and neuropathy were more prevalent in patients with the Sandhoff variant than in those with the Tay-Sachs variant. However, dysphagia, sphincter incontinence, and sleep problems occurred earlier in those with the Tay-Sachs variant. Cerebellar atrophy was the most common finding on brain MRI (52.9%). The median survival time among the studied and reviewed patients was 14.5 years. The genotype-phenotype correlation revealed that in patients with the Tay-Sachs variant, the presence of R178H and R499H mutations was predictive of an early onset and rapidly progressive course. The presence of either G269S or W474C mutations was associated with a later onset of symptoms along with a more slowly progressive disease course. CONCLUSIONS Juvenile GM2 gangliosidosis is clinically heterogeneous, not only in terms of age of onset and clinical features but also with regard to the course of the disease. In general, the earlier the onset of symptoms, the more rapidly the disease progresses. The Tay-Sachs and Sandhoff variants differed somewhat in the frequency of specific clinical characteristics. Speech deterioration progressed more rapidly than gait abnormalities in both the Tay-Sachs variant and Sandhoff variant groups. Among patients with the Tay-Sachs variant, the HEXA genotype showed a significant correlation with the clinical course.
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Affiliation(s)
- Gustavo H. B. Maegawa
- Division of Clinical and Metabolic Genetics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Tracy Stockley
- Department of Paediatrics, Paediatric Laboratory Medicine, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Michael Tropak
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Brenda Banwell
- Division of Neurology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Susan Blaser
- Department of Paediatrics, Diagnostic Imaging, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Fernando Kok
- Centro do Genoma Humano, University of Sao Paulo, Sao Paulo, Brazil
| | - Roberto Giugliani
- Medical Genetics Service, Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil
| | - Don Mahuran
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Joe T. R. Clarke
- Division of Clinical and Metabolic Genetics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Research Institute, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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9
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Triggs-Raine B, Mahuran DJ, Gravel RA. Naturally occurring mutations in GM2 gangliosidosis: a compendium. ADVANCES IN GENETICS 2002; 44:199-224. [PMID: 11596984 DOI: 10.1016/s0065-2660(01)44081-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- B Triggs-Raine
- Department of Biochemistry and Medical Genetics University of Manitoba, Winnipeg, Canada.
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Gomez-Lira M, Mottes M, Perusi C, Pignatti PF, Rizzuto N, Gatti R, Salviati A. A novel 4-bp deletion creates a premature stop codon and dramatically decreases HEXB mRNA levels in a severe case of Sandhoff disease. Mol Cell Probes 2001; 15:75-9. [PMID: 11292324 DOI: 10.1006/mcpr.2000.0342] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We present the molecular genetic analysis of an infantile-onset Sandhoff disease patient. Genomic DNA amplification, heteroduplex analysis, cloning and sequencing revealed a 4-bp deletion in exon 4 (497 DeltaAGTT). The result is a frameshift mutation that leads to a stop codon in exon 5. This mutation is associated with a dramatic decrease of HEXB mRNA levels.
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Affiliation(s)
- M Gomez-Lira
- Dipartimento Materno Infantile e di Biologia e Genetica, Sezione Biologia e Genetica, Università di Verona, Strada Le Grazie 8, Verona, 37134, Italia.
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11
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Furihata K, Drousiotou A, Hara Y, Christopoulos G, Stylianidou G, Anastasiadou V, Ueno I, Ioannou P. Novel splice site mutation at IVS8 nt 5 of HEXB responsible for a Greek-Cypriot case of Sandhoff disease. Hum Mutat 2000; 13:38-43. [PMID: 9888387 DOI: 10.1002/(sici)1098-1004(1999)13:1<38::aid-humu4>3.0.co;2-s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Sandhoff disease is caused by abnormalities in HEXB gene encoding the beta-subunit of beta-hexosaminidase. In this study, we analyzed the HEXB gene of a Sandhoff carrier in the Greek-Cypriot community. A G to C transversion was identified in one allele of her HEXB gene at position 5 of the 5'-splice site of intron 8 (IVS8 nt5). One of 13 cDNA clones derived from her lymphocyte HEXB mRNA lacked the last four nucleotides "GTTG" of exon 8, which created a premature termination codon at 11 codons downstream. In vivo transcription of the mutant HEXB gene fragment in CHO cells resulted in deletion of the "GTTG." The mutation has not been found in 40 DNA samples from anonymous donors, indicating that this is not a polymorphism in the Cypriot population. These results clearly indicate that the splice site mutation at IVS8 nt5 is responsible for this case of Sandhoff disease.
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Affiliation(s)
- K Furihata
- Department of Laboratory Medicine, Shinshu University School of Medicine, Matsumoto, Japan.
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12
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Kleiman FE, Ramírez AO, Dodelson de Kremer R, Gravel RA, Argaraña CE. A frequent TG deletion near the polyadenylation signal of the human HEXB gene: occurrence of an irregular DNA structure and conserved nucleotide sequence motif in the 3' untranslated region. Hum Mutat 2000; 12:320-9. [PMID: 9792408 DOI: 10.1002/(sici)1098-1004(1998)12:5<320::aid-humu5>3.0.co;2-h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
While screening for new mutations in the HEXB gene, which encodes the beta-subunit of beta-hexosaminidase, a TG deletion (deltaTG) was found in the 3' untranslated region (3'UTR) of the gene, 7 bp upstream from the polyadenylation signal. Examination of DNA samples of 145 unrelated Argentinean individuals from different racial backgrounds showed that the deltaTG allele was present with a frequency of approximately 0.1, compared with the wild-type (WT) allele. The deletion was not associated with infantile or variant forms of Sandhoff disease when present in combination with a deleterious allele. Total Hex and Hex B enzymatic activities measured in individuals heterozygous for deltaTG and a null allele, IVS-2 + 1G-->A (G-->A), were approximately 30% lower than the activities of G-->A/WT individuals. Analysis of the HEXB mRNA from leukocytes of deltaTG/WT individuals by RT-PCR of the 3'UTR showed that the deltaTG allele is present at lower level than the WT allele. By polyacrylamide gel electrophoresis, it was determined that a PCR fragment containing the +TG version of the 3'UTR of the HEXB gene had an irregular structure. On inspection of genes containing a TG dinucleotide upstream from the polyadenylation signal we found that this dinucleotide was part of a conserved sequence (TGTTTT) immersed in a A/T-rich region. This sequence arrangement was present in more than 40% analyzed eukaryotic mRNAs, including in the human, mouse and cat HEXB genes. The significance of the TG deletion in reference to Sandhoff disease as well as the possible functional role of the consensus sequence and the DNA structure of the 3'UTR are considered.
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Affiliation(s)
- F E Kleiman
- Centro de Investigaciones en Química Biológica de Córdoba-CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina
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Abstract
Genotyping individuals for Tay-Sachs disease (TSD) is mainly based on the heat lability of beta-hexosaminidase (Hex) A (alphabeta) and the heat stability of Hex B (betabeta). Mutations in the HEXB gene encoding the beta-subunits of Hex that result in heat-labile Hex B thus may lead to erroneous enzymatic genotyping regarding TSD. Utilizing single strand conformation polymorphism (SSCP) analysis for all 14 exons of HEXB followed by direct sequencing of aberrant fragments, we screened individuals whose Hex B was heat labile. A novel heat labile mutation, previously concluded to exist in the HEXB gene, was identified among Jews and Arabs as 1627 G-->A. One individual with heat labile Hex B (HLB) was negative for this novel mutation and for the known 1514 G-->A HLB mutation, proving that there exists at least one other unidentified HLB mutation. Based on these results, it is advisable to perform DNA tests for 1627 G-->A mutation in suspected HLB individuals.
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Affiliation(s)
- G Narkis
- Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Israel
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Mahuran DJ. Biochemical consequences of mutations causing the GM2 gangliosidoses. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1455:105-38. [PMID: 10571007 DOI: 10.1016/s0925-4439(99)00074-5] [Citation(s) in RCA: 199] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The hydrolysis of GM2-ganglioside is unusual in its requirements for the correct synthesis, processing, and ultimate combination of three gene products. Whereas two of these proteins are the alpha- (HEXA gene) and beta- (HEXB) subunits of beta-hexosaminidase A, the third is a small glycolipid transport protein, the GM2 activator protein (GM2A), which acts as a substrate specific co-factor for the enzyme. A deficiency of any one of these proteins leads to storage of the ganglioside, primarily in the lysosomes of neuronal cells, and one of the three forms of GM2-gangliosidosis, Tay-Sachs disease, Sandhoff disease or the AB-variant form. Studies of the biochemical impact of naturally occurring mutations associated with the GM2 gangliosidoses on mRNA splicing and stability, and on the intracellular transport and stability of the affected protein have provided some general insights into these complex cellular mechanisms. However, such studies have revealed little in the way of structure-function information on the proteins. It appears that the detrimental effect of most mutations is not specifically on functional elements of the protein, but rather on the proteins' overall folding and/or intracellular transport. The few exceptions to this generalization are missense mutations at two codons in HEXA, causing the unique biochemical phenotype known as the B1-variant, and one codon in both the HEXB and GM2A genes. Biochemical characterization of these mutations has led to the localization of functional residues and/or domains within each of the encoded proteins.
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Affiliation(s)
- D J Mahuran
- Research Institute, The Hospital for Sick Children, Toronto, Ont, Canada.
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Gomez-Lira M, Perusi C, Mottes M, Pignatti PF, Rizzuto N, Gatti R, Salviati A. Splicing mutation causes infantile Sandhoff disease. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1096-8628(19980123)75:3<330::aid-ajmg21>3.0.co;2-p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Affiliation(s)
- V Gieselmann
- Department of Biochemistry II, Georg August Universität, Göttingen, Germany
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Gomez-Lira M, Perusi C, Brutti N, Farnetani MA, Margollicci MA, Rizzuto N, Pignatti PF, Salviati A. A 48-bp insertion between exon 13 and 14 of the HEXB gene causes infantile-onset Sandhoff disease. Hum Mutat 1995; 6:260-2. [PMID: 8535449 DOI: 10.1002/humu.1380060313] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- M Gomez-Lira
- Istituto di Biologia e Genetica, Università di Verona, Italy
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Bolhuis PA, Ponne NJ, Bikker H, Baas F, Vianney de Jong JM. Molecular basis of an adult form of Sandhoff disease: substitution of glutamine for arginine at position 505 of the beta-chain of beta-hexosaminidase results in a labile enzyme. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1182:142-6. [PMID: 8357844 DOI: 10.1016/0925-4439(93)90134-m] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Sandhoff disease is a lysosomal storage disorder characterized by accumulation of GM2 ganglioside due to mutations in the beta-chain of beta-hexosaminidase. Hexosaminidase activity is negligible in infantile Sandhoff disease whereas residual activity is present in juvenile and adult forms. Here we report the molecular basis of the first described adult form of Sandhoff disease. Southern analysis of chromosomal DNA indicated the absence of chromosomal deletions in the gene encoding the beta-chain. Northern analysis of RNA from cultured fibroblasts demonstrated that at least one of the beta-chain alleles was transcribed into normal-length mRNA. Sequence analysis of the entire cDNA prepared from poly-adenylated RNA showed that only one point mutation was present, consisting of a G-->A transition at nucleotide position 1514. This mutation changes the electric charge at amino acid position 505 by substitution of glutamine for arginine in a highly conserved part of the beta-chain, present even in the slime mold Dictyostelium discoideum. The nucleotide transition generated a new restriction site for DdeI, which was present in only one of the alleles of the patient. Reverse transcription of mRNA followed by restriction with DdeI resulted in complete digestion at the mutation site, demonstrating that the second allele was of an mRNA-negative type. Transfection of COS cells with a cDNA construct containing the mutation but otherwise the normal sequence resulted in the expression of a labile form of beta-hexosaminidase. These results show that the patient's is a genetic compound, and that the lability of beta-hexosaminidase found in this form of Sandhoff disease is based on a single nucleotide transition.
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Affiliation(s)
- P A Bolhuis
- Academic Medical Center, Department of Neurology, Amsterdam, The Netherlands
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Brown CA, McInnes B, de Kremer RD, Mahuran DJ. Characterization of two HEXB gene mutations in Argentinean patients with Sandhoff disease. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1180:91-8. [PMID: 1390948 DOI: 10.1016/0925-4439(92)90031-h] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Beta-hexosaminidase A (beta-N-acetyl-D-hexosaminidase, EC 3.2.1.5.2) is a lysosomal hydrolase composed of an alpha- and a beta-subunit. It is responsible for the degradation of GM2 ganglioside. Mutations in the HEXB gene encoded beta-subunit cause a form of GM2 gangliosidosis known as Sandhoff disease. Although this is a rare disease in the general population, several geographically isolated groups have a high carrier frequency. Most notably, a 1 in 16-29 carrier frequency has been reported for an Argentinean population living in an area contained within a 375-km radius from Córdoba. Analysis of the genomic DNA of two patients from this region revealed that one was homozygous for a G to A substitution at the 5' donor splice site of intron 2. This mutation completely abolishes normal mRNA splicing. The other patient was a compared of the intron 2 G-->A substitution and a second allele due to a 4-bp deletion in exon 7. The beta-subunit mRNA of this allele is unstable, presumably as a result of an early stop codon introduced by the deletion. Two novel PCR-based assays were developed to detect these mutations. We suggest that one of these assays could be modified and used as a rapid screening procedure for 5' donor splice site defects in other genes. These results provide a further example of the genetic heterogeneity that can exist even in a small geographically isolated population.
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Affiliation(s)
- C A Brown
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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