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Hattori Y, Sawada T, Kido J, Sugawara K, Yoshida S, Matsumoto S, Inoue T, Hirose S, Nakamura K. Frequency of iduronate-2-sulfatase gene variants detected in newborn screening for mucopolysaccharidosis type II in Japan. Mol Genet Metab Rep 2023; 37:101003. [PMID: 38053932 PMCID: PMC10694771 DOI: 10.1016/j.ymgmr.2023.101003] [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: 05/05/2023] [Revised: 08/19/2023] [Accepted: 08/20/2023] [Indexed: 12/07/2023] Open
Abstract
Mucopolysaccharidosis II (MPS II) is an X-linked, recessive, inborn metabolic disorder caused by defects in iduronate-2-sulfatase (IDS). The age at onset, disease severity, and rate of progression vary significantly among patients. This disease is classified into severe or mild forms depending on neurological symptom involvement. The severe form is associated with progressive cognitive decline while the mild form is predominantly associated with somatic features. Newborn screening (NBS) for MPS II has been performed since December 2016, mainly in Kyushu, Japan, where 197,700 newborns were screened using a fluorescence enzyme activity assay of dried blood spots. We diagnosed one newborn with MPS II with lower IDS activity, elevated urinary glycosaminoglycans, and a novel variant of the IDS gene. In the future, NBS for MPS II is expected to be performed in many regions of Japan and will contribute to the detection of more patients with MPS II, which is crucial to the early treatment of the disorder.
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Affiliation(s)
- Yusuke Hattori
- Department of Pediatrics, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
| | - Takaaki Sawada
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Jun Kido
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Keishin Sugawara
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | | | - Shirou Matsumoto
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takahito Inoue
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
- Department of Pediatrics, Fukuoka University Chikushi Hospital, Fukuoka, Japan
| | - Shinichi Hirose
- General Medical Research Center, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Kimitoshi Nakamura
- Department of Pediatrics, Kumamoto University Hospital, Kumamoto, Japan
- Department of Pediatrics, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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Effect of Anti-Iduronate 2-Sulfatase Antibodies in Patients with Mucopolysaccharidosis Type II Treated with Enzyme Replacement Therapy. J Pediatr 2022; 248:100-107.e3. [PMID: 35568060 DOI: 10.1016/j.jpeds.2022.05.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/23/2022] [Accepted: 05/06/2022] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To assess the relationship between anti-Iduronate 2-sulfatase (IDS) antibodies, IDS genotypes, phenotypes and their impact in patients with enzyme replacement therapy (ERT)-treated Mucopolysaccharidosis type II. STUDY DESIGN Dutch patients treated with ERT were analyzed in this observational cohort study. Antibody titers were determined by enzyme-linked immunosorbent assay. Neutralizing effects were measured in fibroblasts. Pharmacokinetic analysis of ERT was combined with immunoprecipitation. Urinary glycosaminoglycans were measured using mass spectrometry and dimethylmethylene blue. RESULTS Eight of 17 patients (47%) developed anti-IDS antibodies. Three patients with the severe, neuronopathic phenotype, two of whom did not express IDS protein, showed sustained antibodies for up to 10 years of ERT. Titers of 1:5120 or greater inhibited cellular IDS uptake and/or intracellular activity in vitro. In 1 patient who was neuronopathic with a titer of 1:20 480, pharmacokinetic analysis showed that all plasma recombinant IDS was antibody bound. This finding was not the case in 2 patients who were not neuronopathic with a titer of 1:1280 or less. Patients with sustained antibody titers showed increased urinary glycosaminoglycan levels compared with patients with nonsustained or no-low titers. CONCLUSIONS Patients with the neuronopathic form and lack of IDS protein expression were most at risk to develop sustained anti-IDS antibody titers, which inhibited IDS uptake and/or activity in vitro, and the efficacy of ERT in patients by lowering urinary glycosaminoglycan levels.
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Lin HY, Chang YH, Lee CL, Tu YR, Lo YT, Hung PW, Niu DM, Liu MY, Liu HY, Chen HJ, Kao SM, Wang LY, Ho HJ, Chuang CK, Lin SP. Newborn Screening Program for Mucopolysaccharidosis Type II and Long-Term Follow-Up of the Screen-Positive Subjects in Taiwan. J Pers Med 2022; 12:jpm12071023. [PMID: 35887520 PMCID: PMC9320252 DOI: 10.3390/jpm12071023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 06/18/2022] [Accepted: 06/20/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Mucopolysaccharidosis II (MPS II) is an X-linked disorder resulting from a deficiency in lysosomal enzyme iduronate-2-sulfatase (IDS), which causes the accumulation of glycosaminoglycans (GAGs) in the lysosomes of many tissues and organs, leading to progressive cellular dysfunction. An MPS II newborn screening program has been available in Taiwan since 2015. The aim of the current study was to collect and analyze the long-term follow-up data of the screen-positive subjects in this program. Methods: From August 2015 to April 2022, 548,624 newborns were screened for MPS II by dried blood spots using tandem mass spectrometry, of which 202 suspected infants were referred to our hospital for confirmation. The diagnosis of MPS II was confirmed by IDS enzyme activity assay in leukocytes, quantitative determination of urinary GAGs by mass spectrometry, and identification of the IDS gene variant. Results: Among the 202 referred infants, 10 (5%) with seven IDS gene variants were diagnosed with confirmed MPS II (Group 1), 151 (75%) with nine IDS gene variants were classified as having suspected MPS II or pseudodeficiency (Group 2), and 41 (20%) with five IDS gene variants were classified as not having MPS II (Group 3). Long-term follow-up every 6 months was arranged for the infants in Group 1 and Group 2. Intravenous enzyme replacement therapy (ERT) was started in four patients at 1, 0.5, 0.4, and 0.5 years of age, respectively. Three patients also received hematopoietic stem cell transplantation (HSCT) at 1.5, 0.9, and 0.6 years of age, respectively. After ERT and/or HSCT, IDS enzyme activity and the quantity of urinary GAGs significantly improved in all of these patients compared with the baseline data. Conclusions: Because of the progressive nature of MPS II, early diagnosis via a newborn screening program and timely initiation of ERT and/or HSCT before the occurrence of irreversible organ damage may lead to better clinical outcomes. The findings of the current study could serve as baseline data for the analysis of the long-term effects of ERT and HSCT in these patients.
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Affiliation(s)
- Hsiang-Yu Lin
- Department of Pediatrics, MacKay Memorial Hospital, Taipei 10449, Taiwan; (H.-Y.L.); (Y.-H.C.); (C.-L.L.)
- Department of Medical Research, MacKay Memorial Hospital, Taipei 10449, Taiwan;
- The Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (P.-W.H.)
- Department of Medicine, MacKay Medical College, New Taipei City 25245, Taiwan
- MacKay Junior College of Medicine, Nursing and Management, Taipei 11260, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40402, Taiwan
| | - Ya-Hui Chang
- Department of Pediatrics, MacKay Memorial Hospital, Taipei 10449, Taiwan; (H.-Y.L.); (Y.-H.C.); (C.-L.L.)
- The Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (P.-W.H.)
| | - Chung-Lin Lee
- Department of Pediatrics, MacKay Memorial Hospital, Taipei 10449, Taiwan; (H.-Y.L.); (Y.-H.C.); (C.-L.L.)
- Department of Medical Research, MacKay Memorial Hospital, Taipei 10449, Taiwan;
- The Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (P.-W.H.)
- Department of Medicine, MacKay Medical College, New Taipei City 25245, Taiwan
- MacKay Junior College of Medicine, Nursing and Management, Taipei 11260, Taiwan
| | - Yuan-Rong Tu
- Department of Medical Research, MacKay Memorial Hospital, Taipei 10449, Taiwan;
| | - Yun-Ting Lo
- The Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (P.-W.H.)
| | - Pei-Wen Hung
- The Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (P.-W.H.)
| | - Dau-Ming Niu
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
| | - Mei-Ying Liu
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei 10699, Taiwan; (M.-Y.L.); (H.-Y.L.); (H.-J.C.); (S.-M.K.)
| | - Hsin-Yun Liu
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei 10699, Taiwan; (M.-Y.L.); (H.-Y.L.); (H.-J.C.); (S.-M.K.)
| | - Hsiao-Jan Chen
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei 10699, Taiwan; (M.-Y.L.); (H.-Y.L.); (H.-J.C.); (S.-M.K.)
| | - Shu-Min Kao
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei 10699, Taiwan; (M.-Y.L.); (H.-Y.L.); (H.-J.C.); (S.-M.K.)
| | - Li-Yun Wang
- Taipei Institute of Pathology, Neonatal Screening Center, Taipei 10374, Taiwan; (L.-Y.W.); (H.-J.H.)
| | - Huey-Jane Ho
- Taipei Institute of Pathology, Neonatal Screening Center, Taipei 10374, Taiwan; (L.-Y.W.); (H.-J.H.)
| | - Chih-Kuang Chuang
- Department of Medical Research, MacKay Memorial Hospital, Taipei 10449, Taiwan;
- College of Medicine, Fu-Jen Catholic University, Taipei 24205, Taiwan
- Correspondence: (C.-K.C.); (S.-P.L.); Tel.: +886-2-2809-4661 (ext. 2348) (C.-K.C.); +886-2-2543-3535 (ext. 3090) (S.-P.L.); Fax: +886-2-2808-5952 (C.-K.C.); +886-2-2543-3642 (S.-P.L.)
| | - Shuan-Pei Lin
- Department of Pediatrics, MacKay Memorial Hospital, Taipei 10449, Taiwan; (H.-Y.L.); (Y.-H.C.); (C.-L.L.)
- Department of Medical Research, MacKay Memorial Hospital, Taipei 10449, Taiwan;
- The Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (P.-W.H.)
- Department of Medicine, MacKay Medical College, New Taipei City 25245, Taiwan
- Department of Infant and Child Care, National Taipei University of Nursing and Health Sciences, Taipei 11219, Taiwan
- Correspondence: (C.-K.C.); (S.-P.L.); Tel.: +886-2-2809-4661 (ext. 2348) (C.-K.C.); +886-2-2543-3535 (ext. 3090) (S.-P.L.); Fax: +886-2-2808-5952 (C.-K.C.); +886-2-2543-3642 (S.-P.L.)
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Keegan NP, Wilton SD, Fletcher S. Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 12:806946. [PMID: 35140743 PMCID: PMC8819188 DOI: 10.3389/fgene.2021.806946] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/09/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding pre-mRNA splicing is crucial to accurately diagnosing and treating genetic diseases. However, mutations that alter splicing can exert highly diverse effects. Of all the known types of splicing mutations, perhaps the rarest and most difficult to predict are those that activate pseudoexons, sometimes also called cryptic exons. Unlike other splicing mutations that either destroy or redirect existing splice events, pseudoexon mutations appear to create entirely new exons within introns. Since exon definition in vertebrates requires coordinated arrangements of numerous RNA motifs, one might expect that pseudoexons would only arise when rearrangements of intronic DNA create novel exons by chance. Surprisingly, although such mutations do occur, a far more common cause of pseudoexons is deep-intronic single nucleotide variants, raising the question of why these latent exon-like tracts near the mutation sites have not already been purged from the genome by the evolutionary advantage of more efficient splicing. Possible answers may lie in deep intronic splicing processes such as recursive splicing or poison exon splicing. Because these processes utilize intronic motifs that benignly engage with the spliceosome, the regions involved may be more susceptible to exonization than other intronic regions would be. We speculated that a comprehensive study of reported pseudoexons might detect alignments with known deep intronic splice sites and could also permit the characterisation of novel pseudoexon categories. In this report, we present and analyse a catalogue of over 400 published pseudoexon splice events. In addition to confirming prior observations of the most common pseudoexon mutation types, the size of this catalogue also enabled us to suggest new categories for some of the rarer types of pseudoexon mutation. By comparing our catalogue against published datasets of non-canonical splice events, we also found that 15.7% of pseudoexons exhibit some splicing activity at one or both of their splice sites in non-mutant cells. Importantly, this included seven examples of experimentally confirmed recursive splice sites, confirming for the first time a long-suspected link between these two splicing phenomena. These findings have the potential to improve the fidelity of genetic diagnostics and reveal new targets for splice-modulating therapies.
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Affiliation(s)
- Niall P. Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
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Nationwide Newborn Screening Program for Mucopolysaccharidoses in Taiwan and an Update of the "Gold Standard" Criteria Required to Make a Confirmatory Diagnosis. Diagnostics (Basel) 2021; 11:diagnostics11091583. [PMID: 34573925 PMCID: PMC8465393 DOI: 10.3390/diagnostics11091583] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/29/2021] [Accepted: 08/29/2021] [Indexed: 11/17/2022] Open
Abstract
Mucopolysaccharidoses (MPSs) are a group of lysosomal storage diseases (LSDs) caused by an inherited gene defect. MPS patients can remain undetected unless the initial signs or symptoms have been identified. Newborn screening (NBS) programs for MPSs have been implemented in Taiwan since 2015, and more than 48.5% of confirmed cases of MPS have since been referred from these NBS programs. The purpose of this study was to report the current status of NBS for MPSs in Taiwan and update the gold standard criteria required to make a confirmative diagnosis of MPS, which requires the presence of the following three laboratory findings: (1) elevation of individual urinary glycosaminoglycan (GAG)-derived disaccharides detected by MS/MS-based assay; (2) deficient activity of a particular leukocyte enzyme by fluorometric assay; and (3) verification of heterogeneous or homogeneous variants by Sanger sequencing or next generation sequencing. Up to 30 April 2021, 599,962 newborn babies have been screened through the NBS programs for MPS type I, II, VI, and IVA, and a total of 255 infants have been referred to MacKay Memorial Hospital for a confirmatory diagnosis. Of these infants, four cases were confirmed to have MPS I, nine cases MPS II, and three cases MPS IVA, with prevalence rates of 0.67, 2.92, and 4.13 per 100,000 live births, respectively. Intensive long-term regular physical and laboratory examinations for asymptomatic infants with confirmed MPS or with highly suspected MPS can enhance the ability to administer ERT in a timely fashion.
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Marazza A, Galli C, Fasana E, Sgrignani J, Burda P, Fassi EMA, Baumgartner M, Cavalli A, Molinari M. Endoplasmic Reticulum and Lysosomal Quality Control of Four Nonsense Mutants of Iduronate 2-Sulfatase Linked to Hunter's Syndrome. DNA Cell Biol 2020; 39:226-234. [PMID: 31895584 DOI: 10.1089/dna.2019.5221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Hunter's syndrome (mucopolysaccharidosis type II) is a rare X-linked lysosomal storage disorder caused by mutations in the iduronate-2-sulfatase (IDS) gene. Motivated by the case of a child affected by this syndrome, we compared the intracellular fate of wild-type IDS (IDSWT) and four nonsense mutations of IDS (IDSL482X, IDSY452X, IDSR443X, and IDSW337X) generating progressively shorter forms of IDS associated with mild to severe forms of the disease. Our analyses revealed formylation of all forms of IDS at cysteine 84, which is a prerequisite for enzymatic activity. After formylation, IDSWT was transported within lysosomes, where it was processed in the mature form of the enzyme. The length of disease-causing deletions correlated with gravity of the folding and transport phenotype, which was anticipated by molecular dynamics analyses. The shortest form of IDS, IDSW337X, was retained in the endoplasmic reticulum (ER) and degraded by the ubiquitin-proteasome system. IDSR443X, IDSY452X, and IDSL482X passed ER quality control and were transported to the lysosomes, but failed lysosomal quality control, resulting in their rapid clearance and in loss-of-function phenotype. Failure of ER quality control inspection is an established cause of loss of function observed in protein misfolding diseases. Our data reveal that fulfillment of ER requirements might not be sufficient, highlight lysosomal quality control as the distal station to control lysosomal enzymes fitness and pave the way for alternative therapeutic interventions.
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Affiliation(s)
- Alessandro Marazza
- Università della Svizzera italiana, Lugano, Switzerland.,Institute for Research in Biomedicine, Bellinzona, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Carmela Galli
- Università della Svizzera italiana, Lugano, Switzerland.,Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Elisa Fasana
- Università della Svizzera italiana, Lugano, Switzerland.,Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Jacopo Sgrignani
- Università della Svizzera italiana, Lugano, Switzerland.,Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Patricie Burda
- Abteilung für Stoffwechselkrankheiten, Kinderspital Zürich, Zurich, Switzerland
| | - Enrico M A Fassi
- Università della Svizzera italiana, Lugano, Switzerland.,Institute for Research in Biomedicine, Bellinzona, Switzerland
| | | | - Andrea Cavalli
- Università della Svizzera italiana, Lugano, Switzerland.,Institute for Research in Biomedicine, Bellinzona, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Maurizio Molinari
- Università della Svizzera italiana, Lugano, Switzerland.,Institute for Research in Biomedicine, Bellinzona, Switzerland.,École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Lin HY, Tu RY, Chern SR, Lo YT, Fran S, Wei FJ, Huang SF, Tsai SY, Chang YH, Lee CL, Lin SP, Chuang CK. Identification and Functional Characterization of IDS Gene Mutations Underlying Taiwanese Hunter Syndrome (Mucopolysaccharidosis Type II). Int J Mol Sci 2019; 21:ijms21010114. [PMID: 31877959 PMCID: PMC6982257 DOI: 10.3390/ijms21010114] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/05/2019] [Accepted: 12/19/2019] [Indexed: 12/24/2022] Open
Abstract
Hunter syndrome (mucopolysaccharidosis II; MPS II) is caused by a defect of the iduronate-2-sulfatase (IDS) gene. Few studies have reported integrated mutation data of Taiwanese MPS II phenotypes. In this study, we summarized genotype and phenotype correlations of confirmed MPS II patients and asymptomatic MPS II infants in Taiwan. Regular polymerase chain reaction and DNA sequencing were used to identify genetic abnormalities of 191 cases, including 51 unrelated patients with confirmed MPS II and 140 asymptomatic infants. IDS activity was analyzed in individual novel IDS variants using in vitro expression studies. Nineteen novel mutations were identified, in which the percentages of IDS activity of the novel missense mutations c.137A>C, c.311A>T, c.454A>C, c.797C>G, c.817C>T, c.998C>T, c.1106C>G, c.1400C>T, c.1402C>T, and c.1403G>A were significantly decreased (p < 0.001), c.254C>T and c.1025A>G were moderately decreased (p < 0.01), and c.851C>T was slightly decreased (p < 0.05) comparing with normal enzyme activity. The activities of the other six missense mutations were reduced but were insignificant. The results of genomic studies and their phenotypes were highly correlated. A greater understanding of the positive correlations may help to prevent the irreversible manifestations of Hunter syndrome, particularly in infants suspected of having asymptomatic MPS II. In addition, urinary glycosaminoglycan assay is important to diagnose Hunter syndrome since gene mutations are not definitive (could be non-pathogenic).
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Affiliation(s)
- Hsiang-Yu Lin
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City 25160, Taiwan; (H.-Y.L.); (R.-Y.T.); (S.-R.C.); (S.F.); (F.-J.W.)
- Department of Pediatrics, MacKay Memorial Hospital, Taipei 10449, Taiwan
- MacKay Junior College of Medicine, Nursing and Management, New Taipei City 25245, Taiwan
- Department of Medicine, MacKay Medical College, New Taipei City 25245, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40402, Taiwan
- Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (S.-Y.T.); (Y.-H.C.)
| | - Ru-Yi Tu
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City 25160, Taiwan; (H.-Y.L.); (R.-Y.T.); (S.-R.C.); (S.F.); (F.-J.W.)
| | - Schu-Rern Chern
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City 25160, Taiwan; (H.-Y.L.); (R.-Y.T.); (S.-R.C.); (S.F.); (F.-J.W.)
| | - Yun-Ting Lo
- Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (S.-Y.T.); (Y.-H.C.)
| | - Sisca Fran
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City 25160, Taiwan; (H.-Y.L.); (R.-Y.T.); (S.-R.C.); (S.F.); (F.-J.W.)
| | - Fang-Jie Wei
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City 25160, Taiwan; (H.-Y.L.); (R.-Y.T.); (S.-R.C.); (S.F.); (F.-J.W.)
| | - Sung-Fa Huang
- Department of Laboratory Medicine, MacKay Memorial Hospital, New Taipei City 25160, Taiwan;
| | - Shin-Yu Tsai
- Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (S.-Y.T.); (Y.-H.C.)
| | - Ya-Hui Chang
- Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (S.-Y.T.); (Y.-H.C.)
| | - Chung-Lin Lee
- Department of Pediatrics, MacKay Memorial Hospital, Hsinchu 30071, Taiwan;
- Institute of Clinical Medicine, National Yang-Ming University, Taipei 11221, Taiwan
| | - Shuan-Pei Lin
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City 25160, Taiwan; (H.-Y.L.); (R.-Y.T.); (S.-R.C.); (S.F.); (F.-J.W.)
- Department of Pediatrics, MacKay Memorial Hospital, Taipei 10449, Taiwan
- MacKay Junior College of Medicine, Nursing and Management, New Taipei City 25245, Taiwan
- Department of Medicine, MacKay Medical College, New Taipei City 25245, Taiwan
- Rare Disease Center, MacKay Memorial Hospital, Taipei 10449, Taiwan; (Y.-T.L.); (S.-Y.T.); (Y.-H.C.)
- Department of Infant and Child Care, National Taipei University of Nursing and Health Sciences, Taipei 11219, Taiwan
- Correspondence: (S.-P.L.); (C.-K.C.)
| | - Chih-Kuang Chuang
- Department of Medical Research, MacKay Memorial Hospital, New Taipei City 25160, Taiwan; (H.-Y.L.); (R.-Y.T.); (S.-R.C.); (S.F.); (F.-J.W.)
- College of Medicine, Fu-Jen Catholic University, New Taipei City 24205, Taiwan
- Correspondence: (S.-P.L.); (C.-K.C.)
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Chan MJ, Liao HC, Gelb MH, Chuang CK, Liu MY, Chen HJ, Kao SM, Lin HY, Huang YH, Kumar AB, Chennamaneni NK, Pendem N, Lin SP, Chiang CC. Taiwan National Newborn Screening Program by Tandem Mass Spectrometry for Mucopolysaccharidoses Types I, II, and VI. J Pediatr 2019; 205:176-182. [PMID: 30409495 PMCID: PMC6623979 DOI: 10.1016/j.jpeds.2018.09.063] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/24/2018] [Accepted: 09/26/2018] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To evaluate the initial cutoff values, rates of screen positives, and genotypes for the large-scale newborn screening program for multiple mucopolysaccharidoses (MPS) in Taiwan. STUDY DESIGN More than 100 000 dried blood spots were collected consecutively as part of the national Taiwan newborn screening programs. Enzyme activities were measured by tandem mass spectrometry from dried blood spot punches. Genotypes were obtained when a second newborn screening specimen again had a decreased enzyme activity. Additional clinical evaluation was then initiated based on enzyme activity and/or genotype. RESULTS Molecular genetic analysis for cases with low enzyme activity revealed 5 newborns with pathogenic alpha-L-iduronidase mutations, 3 newborns with pathogenic iduronate-2-sulfatase mutations, and 1 newborn was a carrier of an arylsulfatase B mutation. Several variants of unknown pathogenic significance were also identified, most likely causing pseudodeficiency. CONCLUSIONS The highly robust tandem mass spectrometry-based enzyme assays for MPS-I, MPS-II, and MPS-VI allow for high-throughput newborn screening for these lysosomal storage disorders. Optimized cutoff values combined with second tier testing could largely eliminate false-positive results. Accordingly, newborn screening for these lysosomal storage disorders is possible.
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Affiliation(s)
- Min-Ju Chan
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Hsuan-Chieh Liao
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Michael H. Gelb
- Department of Chemistry, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Chih-Kuang Chuang
- Division of Genetics and Metabolism, Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
| | - Mei-Ying Liu
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Hsiao-Jan Chen
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Shu-Min Kao
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Hsiang-Yu Lin
- Division of Genetics and Metabolism, Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
- Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan
| | - You-Hsin Huang
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
| | - Arun Babu Kumar
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | | | - Nagendar Pendem
- Department of Chemistry, University of Washington, Seattle, WA, USA
| | - Shuan-Pei Lin
- Division of Genetics and Metabolism, Department of Medical Research, Mackay Memorial Hospital, Taipei, Taiwan
- Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan
| | - Chuan-Chi Chiang
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
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9
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Zanetti A, D’Avanzo F, Rigon L, Rampazzo A, Concolino D, Barone R, Volpi N, Santoro L, Lualdi S, Bertola F, Scarpa M, Tomanin R. Molecular diagnosis of patients affected by mucopolysaccharidosis: a multicenter study. Eur J Pediatr 2019; 178:739-753. [PMID: 30809705 PMCID: PMC6459791 DOI: 10.1007/s00431-019-03341-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 02/05/2019] [Accepted: 02/06/2019] [Indexed: 11/25/2022]
Abstract
Mucopolysaccharidoses (MPS) are a subgroup of 11 monogenic lysosomal storage disorders due to the deficit of activity of the lysosomal hydrolases deputed to the degradation of mucopolysaccharides. Although individually rare, all together they account for at least 1:25,000 live births. In this study, we present the genetic analysis of a population of 71 MPS patients enrolled in a multicenter Italian study. We re-annotated all variants, according to the latest recommendations, and re-classified them as suggested by the American College of Medical Genetics and Genomics. Variant distribution per type was mainly represented by missense mutations. Overall, 10 patients had received no molecular diagnosis, although 6 of them had undergone either HSCT or ERT, based on clinical and enzymatic evaluations. Moreover, nine novel variants are reported.Conclusions: Our analysis underlines the need to complete the molecular diagnosis in patients previously diagnosed only on a biochemical basis, suggests a periodical re-annotation of the variants and solicits their deposition in public databases freely available to clinicians and researchers. We strongly recommend a molecular diagnosis based on the analysis of the "trio" instead of the sole proband. These recommendations will help to obtain a complete and correct diagnosis of mucopolysaccharidosis, rendering also possible genetic counseling. What is known • MPS are a group of 11 metabolic genetic disorders due to deficits of enzymes involved in the mucopolysaccharides degradation. • Molecular analysis is commonly performed to confirm enzymatic assays. What is new • Eighty-six percent of the 71 patients we collected received a molecular diagnosis; among them, 9 novel variants were reported. • We stress the importance of molecular diagnosis in biochemically diagnosed patients, encourage a periodical re-annotation of variants according to the recent nomenclature and their publication in open databases.
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Affiliation(s)
- Alessandra Zanetti
- Laboratorio di Diagnosi e Terapia delle Malattie Lisosomiali, Department of Women’s and Children’s Health, University of Padova, Padova, Italy
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Francesca D’Avanzo
- Laboratorio di Diagnosi e Terapia delle Malattie Lisosomiali, Department of Women’s and Children’s Health, University of Padova, Padova, Italy
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Laura Rigon
- Laboratorio di Diagnosi e Terapia delle Malattie Lisosomiali, Department of Women’s and Children’s Health, University of Padova, Padova, Italy
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Angelica Rampazzo
- Laboratorio di Diagnosi e Terapia delle Malattie Lisosomiali, Department of Women’s and Children’s Health, University of Padova, Padova, Italy
| | | | - Rita Barone
- Department of Clinical and Experimental Medicine, Child Neurology and Psychiatry, University of Catania, Catania, Italy
| | - Nicola Volpi
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Lucia Santoro
- Department of Clinical Sciences, Division of Pediatrics, Polytechnic University of Marche, Ospedali Riuniti, Presidio Salesi, Ancona, Italy
| | - Susanna Lualdi
- Laboratorio di Genetica Medica e Biobanche, Istituto Giannina Gaslini, Genoa, Italy
| | - Francesca Bertola
- School of Medicine and Surgery, University of Milano Bicocca, Monza, Italy
| | - Maurizio Scarpa
- Laboratorio di Diagnosi e Terapia delle Malattie Lisosomiali, Department of Women’s and Children’s Health, University of Padova, Padova, Italy
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
| | - Rosella Tomanin
- Laboratorio di Diagnosi e Terapia delle Malattie Lisosomiali, Department of Women’s and Children’s Health, University of Padova, Padova, Italy
- Fondazione Istituto di Ricerca Pediatrica Città della Speranza, Padova, Italy
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10
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Chuang CK, Lin HY, Wang TJ, Huang YH, Chan MJ, Liao HC, Lo YT, Wang LY, Tu RY, Fang YY, Chen TL, Ho HC, Chiang CC, Lin SP. Status of newborn screening and follow up investigations for Mucopolysaccharidoses I and II in Taiwan. Orphanet J Rare Dis 2018; 13:84. [PMID: 29801497 PMCID: PMC5970538 DOI: 10.1186/s13023-018-0816-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 04/26/2018] [Indexed: 11/24/2022] Open
Abstract
Background Mucopolysaccharidoses (MPS) are lysosomal storage diseases in which mutations of genes encoding for lysosomal enzymes cause defects in the degradation of glycosaminoglycans (GAGs). The accumulation of GAGs in lysosomes results in cellular dysfunction and clinical abnormalities. The early initiation of enzyme replacement therapy (ERT) can slow or prevent the development of severe clinical manifestations. MPS I and II newborn screening has been available in Taiwan since August 2015. Infants who failed the recheck at recall were referred to MacKay Memorial Hospital for a detailed confirmatory diagnosis. Methods From August 2015 to November 2017, 294,196 and 153,032 infants were screened using tandem mass spectrometry for MPS I and MPS II, respectively. Of these infants, 84 suspected cases (eight for MPS I; 76 for MPS II) were referred for confirmation. Urinary first-line biochemistry examinations were performed first, including urinary GAG quantification, two-dimensional electrophoresis, and tandem mass spectrometry assay for predominant disaccharides derived from GAGs. If the results were positive, a confirmative diagnosis was made according to the results of leukocyte enzymatic assay and molecular DNA analysis. Leukocyte pellets were isolated from EDTA blood and used for fluorescent α-iduronidase (IDUA) or iduronate-2-sulfatase (IDS) enzymatic assay. DNA sequencing analysis was also performed. Results Normal IDS and IDUA enzyme activities were found in most of the referred cases except for four who were strongly suspected of having MPS I and three who were strongly suspected of having MPS II. Of these infants, three with novel mutations of the IDS gene (c.817C > T, c.1025A > G, and c.311A > T) and four with two missense mutations of the IDUA gene (C.300-3C > G, c.1874A > C; c.1037 T > G, c.1091C > T) showed significant deficiencies in IDS and IDUA enzyme activities (< 5% of mean normal activity), respectively. Urinary dermatan sulfate and heparan sulfate quantitative analyses by tandem mass spectrometry also demonstrated significant elevations. The prevalence rates of MPS I and MPS II in Taiwan were 1.35 and 1.96 per 100,000 live births, respectively. Conclusions The early initiation of ERT for MPS can result in better clinical outcomes. An early confirmatory diagnosis increases the probability of receiving appropriate medical care such as ERT quickly enough to avoid irreversible manifestations. All high risk infants identified in this study so far remain asymptomatic and are presumed to be affected with the attenuated disease variants.
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Affiliation(s)
- Chih-Kuang Chuang
- Division of Genetics and Metabolism, Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan.,College of Medicine, Fu-Jen Catholic University, Taipei, Taiwan
| | - Hsiang-Yu Lin
- Division of Genetics and Metabolism, Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan.,Department of Pediatrics, MacKay Memorial Hospital, Taipei, Taiwan.,The Rare Disease Center, MacKay Memorial Hospital, Taipei, Taiwan.,Department of Early Childhood Care and Education, Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan.,Department of Medicine, MacKay Medical College, Taipei, Taiwan.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Tuan-Jen Wang
- Department of Laboratory Medicine, MacKay Memorial Hospital, Taipei, Taiwan
| | - You-Hsin Huang
- The Rare Disease Center, MacKay Memorial Hospital, Taipei, Taiwan
| | - Min-Ju Chan
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Hsuan-Chieh Liao
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Yun-Ting Lo
- Department of Laboratory Medicine, MacKay Memorial Hospital, Taipei, Taiwan
| | - Li-Yun Wang
- Taipei Institute of Pathology, Neonatal Screening Center, Taipei, Taiwan
| | - Ru-Yi Tu
- Division of Genetics and Metabolism, Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | - Yi-Ya Fang
- Division of Genetics and Metabolism, Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan
| | - Tzu-Lin Chen
- Department of Laboratory Medicine, MacKay Memorial Hospital, Taipei, Taiwan
| | - Hui-Chen Ho
- Taipei Institute of Pathology, Neonatal Screening Center, Taipei, Taiwan
| | - Chuan-Chi Chiang
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan.
| | - Shuan-Pei Lin
- Division of Genetics and Metabolism, Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan. .,Department of Pediatrics, MacKay Memorial Hospital, Taipei, Taiwan. .,The Rare Disease Center, MacKay Memorial Hospital, Taipei, Taiwan. .,Department of Early Childhood Care and Education, Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan. .,Department of Infant and Child Care, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan. .,Departments of Pediatrics and Medical Research, MacKay Memorial Hospital, No. 92, Sec. 2, Chung-Shan N. Rd, Taipei, 10449, Taiwan.
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11
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Vollebregt AAM, Hoogeveen-Westerveld M, Kroos MA, Oussoren E, Plug I, Ruijter GJ, van der Ploeg AT, Pijnappel WWMP. Genotype-phenotype relationship in mucopolysaccharidosis II: predictive power of IDS variants for the neuronopathic phenotype. Dev Med Child Neurol 2017; 59:1063-1070. [PMID: 28543354 DOI: 10.1111/dmcn.13467] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/21/2017] [Indexed: 01/27/2023]
Abstract
AIM Mucopolysaccharidosis type II (MPS II) is caused by variants in the iduronate-2-sulphatase gene (IDS). Patients can be either neuronopathic with intellectual disability, or non-neuronopathic. Few studies have reported on the IDS genotype-phenotype relationship and on the molecular effects involved. We addressed this in a cohort study of Dutch patients with MPS II. METHOD Intellectual performance was assessed for school performance, behaviour, and intelligence. Urinary glycosaminoglycans were quantified by mass spectrometry. IDS variants were analysed in expression studies for enzymatic activity and processing by immunoblotting. RESULTS Six patients had a non-neuronopathic phenotype and 11 a neuronopathic phenotype, three of whom had epilepsy. Total deletion of IDS invariably resulted in the neuronopathic phenotype. Phenotypes of seven known IDS variants were consistent with the literature. Expression studies of nine variants were novel and showed impaired IDS enzymatic activity, aberrant intracellular processing, and elevated urinary excretion of heparan sulphate and dermatan sulphate irrespective of the MPS II phenotype. INTERPRETATION We speculate that very low or cell-type-specific IDS residual activity is sufficient to prevent the neuronal phenotype of MPS II. Whereas the molecular effects of IDS variants do not distinguish between MPS II phenotypes, the IDS genotype is a strong predictor.
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Affiliation(s)
- Audrey A M Vollebregt
- Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Pediatrics, Division of Metabolic Diseases and Genetics, Erasmus Medical Center - Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Marianne Hoogeveen-Westerveld
- Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Molecular Stem Cell Biology, Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marian A Kroos
- Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Molecular Stem Cell Biology, Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Esmee Oussoren
- Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Pediatrics, Division of Metabolic Diseases and Genetics, Erasmus Medical Center - Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Iris Plug
- Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Pediatrics, Division of Metabolic Diseases and Genetics, Erasmus Medical Center - Sophia Children's Hospital, Rotterdam, The Netherlands
| | - George J Ruijter
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ans T van der Ploeg
- Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Pediatrics, Division of Metabolic Diseases and Genetics, Erasmus Medical Center - Sophia Children's Hospital, Rotterdam, The Netherlands
| | - W W M Pim Pijnappel
- Center for Lysosomal and Metabolic Diseases, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Pediatrics, Division of Metabolic Diseases and Genetics, Erasmus Medical Center - Sophia Children's Hospital, Rotterdam, The Netherlands.,Molecular Stem Cell Biology, Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
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12
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Ngiwsara L, Rojnueangnit K, Wattanasirichaigoon D, Tim-Aroon T, Sawangareetrakul P, Champattanachai V, Ketudat-Cairns JR, Svasti J. Molecular analysis of the novel IDS allele in a Thai family with mucopolysaccharidosis type II: The c.928C>T (p.Gln310*) transcript is sensitive to nonsense-mediated mRNA decay. Exp Ther Med 2017; 13:2989-2996. [PMID: 28588666 PMCID: PMC5450777 DOI: 10.3892/etm.2017.4303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/26/2017] [Indexed: 11/06/2022] Open
Abstract
Hunter syndrome (or mucopolysaccharidosis type II, MPS II) is an X-linked recessive disorder induced by a deficiency of the iduronate 2-sulfatase (IDS) enzyme, resulting in the accumulation of glycosaminoglycan substrates, heparan sulfate and dermatan sulfate, in the lysosomes. The progressive accumulation of undegraded metabolites induces cell and tissue dysfunction, leading to multi-systemic pathology. The heterogeneity of clinical phenotypes, ranging from mild to severe forms, results from different mutations in the IDS gene. To date, >550 MPS II causal mutations have been reported in the IDS gene, of which ~10% are nonsense mutations that lead to premature protein termination. In the present study, the IDS mutation causing MPS II in an extended Thai family was identified using IDS enzyme assay and IDS gene exon sequencing. Three family members were enzymatically confirmed to have MPS II and to carry the novel IDS nonsense allele c.928C>T (p.Gln310*). The IDS mRNA levels were evaluated by reverse transcription-quantitative polymerase chain reaction, which demonstrated that all patients exhibited a reduction of IDS mRNA, suggesting its degradation by nonsense-mediated mRNA decay. Expression of wild type and mutant IDS in COS-7 cells revealed that the IDS p.Gln310* mutant lacked IDS activity, consistent with production of a nonfunctional, prematurely truncated protein. Taken together, these results indicate that the IDS c.928C>T (p.Gln310*) mutation is a severe disease-causing mutation for MPS II.
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Affiliation(s)
- Lukana Ngiwsara
- Laboratory of Biochemistry, Chulaborn Research Institute, Bangkok 10210, Thailand
| | - Kitiwan Rojnueangnit
- Pediatrics Department, Faculty of Medicine, Thammasat University, Bangkok 10200, Thailand
| | - Duangrurdee Wattanasirichaigoon
- Department of Pediatrics, Division of Medical Genetics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | - Thipwimol Tim-Aroon
- Department of Pediatrics, Division of Medical Genetics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand
| | | | | | - James R. Ketudat-Cairns
- Laboratory of Biochemistry, Chulaborn Research Institute, Bangkok 10210, Thailand
- School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand
| | - Jisnuson Svasti
- Laboratory of Biochemistry, Chulaborn Research Institute, Bangkok 10210, Thailand
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13
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Dvorakova L, Vlaskova H, Sarajlija A, Ramadza DP, Poupetova H, Hruba E, Hlavata A, Bzduch V, Peskova K, Storkanova G, Kecman B, Djordjevic M, Baric I, Fumic K, Barisic I, Reboun M, Kulhanek J, Zeman J, Magner M. Genotype-phenotype correlation in 44 Czech, Slovak, Croatian and Serbian patients with mucopolysaccharidosis type II. Clin Genet 2017; 91:787-796. [PMID: 27883178 DOI: 10.1111/cge.12927] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/07/2016] [Accepted: 11/17/2016] [Indexed: 11/26/2022]
Abstract
Mucopolysaccharidosis type II (Hunter syndrome, MPS II, OMIM 309900) is an X-linked lysosomal storage disorder caused by deficiency of iduronate-2-sulfatase (IDS). We analyzed clinical and laboratory data from 44 Slavic patients with this disease. In total, 21 Czech, 7 Slovak, 9 Croatian and 7 Serbian patients (43 M/1 F) were included in the study (median age 11.0 years, range 1.2-43 years). Birth prevalence ranged from 1:69,223 (Serbia) to 1:192,626 (Czech Rep.). In the majority of patients (71%), the disease manifested in infancy. Cognitive functions were normal in 10 patients. Four, six and 24 patients had mild, moderate, and severe developmental delay, respectively, typically subsequent to developmental regression (59%). Residual enzyme activity showed no predictive value, and estimation of glycosaminoglycans (GAGs) had only limited importance for prognosis. Mutation analysis performed in 36 families led to the identification of 12 novel mutations, eight of which were small deletions/insertions. Large deletions/rearrangements and all but one small deletion/insertion led to a severe phenotype. This genotype-phenotype correlation was also identified in six cases with recurrent missense mutations. Based on patient genotype, the severity of the disease may be predicted with high probability in approximately half of MPS II patients.
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Affiliation(s)
- L Dvorakova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - H Vlaskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - A Sarajlija
- Department of Metabolism and Clinical Genetics, Mother and Child Health Care Institute of Serbia, Belgrade, Serbia.,School of Medicine, University of Belgrade, Belgrade, Serbia
| | - D P Ramadza
- Department of Pediatrics, University Hospital Center, Zagreb, Croatia
| | - H Poupetova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - E Hruba
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - A Hlavata
- 2nd Department of Pediatrics, Comenius University Medical School in Bratislava University Children's Hospital, Bratislava, Slovakia
| | - V Bzduch
- 1st Department of Pediatrics, Comenius University Medical School in Bratislava University Children's Hospital, Bratislava, Slovakia
| | - K Peskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - G Storkanova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - B Kecman
- Department of Metabolism and Clinical Genetics, Mother and Child Health Care Institute of Serbia, Belgrade, Serbia
| | - M Djordjevic
- Department of Metabolism and Clinical Genetics, Mother and Child Health Care Institute of Serbia, Belgrade, Serbia.,School of Medicine, University of Belgrade, Belgrade, Serbia
| | - I Baric
- Department of Pediatrics, University Hospital Center and University of Zagreb, School of Medicine, Zagreb, Croatia
| | - K Fumic
- Department of Laboratory Diagnostics, University Hospital Centre Zagreb and School of Medicine, Zagreb, Croatia
| | - I Barisic
- Department of Paediatrics, Children's Hospital Zagreb, School of Medicine, Zagreb, Croatia
| | - M Reboun
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - J Kulhanek
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - J Zeman
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic.,Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
| | - M Magner
- Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic
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14
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Chiong MAD, Canson DM, Abacan MAR, Baluyot MMP, Cordero CP, Silao CLT. Clinical, biochemical and molecular characteristics of Filipino patients with mucopolysaccharidosis type II - Hunter syndrome. Orphanet J Rare Dis 2017; 12:7. [PMID: 28077157 PMCID: PMC5225557 DOI: 10.1186/s13023-016-0558-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 12/21/2016] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Mucopolysaccharidosis type II, an X-linked recessive disorder is the most common lysosomal storage disease detected among Filipinos. This is a case series involving 23 male Filipino patients confirmed to have Hunter syndrome. The clinical and biochemical characteristics were obtained and mutation testing of the IDS gene was done on the probands and their female relatives. RESULTS The mean age of the patients was 11.28 (SD 4.10) years with an average symptom onset at 1.2 (SD 1.4) years. The mean age at biochemical diagnosis was 8 (SD 3.2) years. The early clinical characteristics were developmental delay, joint stiffness, coarse facies, recurrent respiratory tract infections, abdominal distention and hernia. Majority of the patients had joint contractures, severe intellectual disability, error of refraction, hearing loss and valvular regurgitation on subspecialists' evaluation. The mean GAG concentration was 506.5 mg (SD 191.3)/grams creatinine while the mean plasma iduronate-2-sulfatase activity was 0.86 (SD 0.79) nmol/mg plasma/4 h. Fourteen (14) mutations were found: 6 missense (42.9%), 4 nonsense (28.6%), 2 frameshift (14.3%), 1 exon skipping at the cDNA level (7.1%), and 1 gross insertion (7.1%). Six (6) novel mutations were observed (43%): p.C422F, p.P86Rfs*44, p.Q121*, p.L209Wfs*4, p.T409R, and c.1461_1462insN[710]. CONCLUSION The age at diagnosis in this series was much delayed and majority of the patients presented with severe neurologic impairment. The results of the biochemical tests did not contribute to the phenotypic classification of patients. The effects of the mutations were consistent with the severe phenotype seen in the majority of the patients.
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Affiliation(s)
- Mary Anne D Chiong
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, 625 Pedro Gil St., Ermita, Manila, 1000, Philippines. .,Department of Pediatrics, University of the Philippines-Philippine General Hospital, Manila, Philippines. .,Department of Pediatrics, College of Medicine, University of Santo Tomas, Manila, Philippines.
| | - Daffodil M Canson
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, 625 Pedro Gil St., Ermita, Manila, 1000, Philippines
| | - Mary Ann R Abacan
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, 625 Pedro Gil St., Ermita, Manila, 1000, Philippines.,Department of Pediatrics, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Melissa Mae P Baluyot
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, 625 Pedro Gil St., Ermita, Manila, 1000, Philippines.,Department of Pediatrics, University of the Philippines-Philippine General Hospital, Manila, Philippines
| | - Cynthia P Cordero
- Department of Clinical Epidemiology, College of Medicine, University of the Philippines, Manila, Philippines
| | - Catherine Lynn T Silao
- Institute of Human Genetics, National Institutes of Health, University of the Philippines Manila, 625 Pedro Gil St., Ermita, Manila, 1000, Philippines.,Department of Pediatrics, University of the Philippines-Philippine General Hospital, Manila, Philippines
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15
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Kosuga M, Mashima R, Hirakiyama A, Fuji N, Kumagai T, Seo JH, Nikaido M, Saito S, Ohno K, Sakuraba H, Okuyama T. Molecular diagnosis of 65 families with mucopolysaccharidosis type II (Hunter syndrome) characterized by 16 novel mutations in the IDS gene: Genetic, pathological, and structural studies on iduronate-2-sulfatase. Mol Genet Metab 2016; 118:190-197. [PMID: 27246110 DOI: 10.1016/j.ymgme.2016.05.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/06/2016] [Accepted: 05/06/2016] [Indexed: 11/17/2022]
Abstract
Mucopolysaccharidosis type II (MPS II: also called as Hunter syndrome) is an X-linked recessive lysosomal storage disorder characterized by the accumulation of extracellular glycosaminoglycans due to the deficiency of the enzyme iduronate-2-sulfatase (IDS). Previous observations suggested that MPS II can be classified into two distinct disease subtypes: (1) severe type of MPS II involves a decline in the cognitive ability of a patient and (2) attenuated type of MPS II exhibits no such intellectual phenotype. To determine whether such disease subtypes of MPS II could be explained by genetic diagnosis, we analyzed mutations in the IDS gene of 65 patients suffering from MPS II among the Japanese population who were diagnosed with both the accumulation of urinary glycosaminoglycans and a decrease in their IDS enzyme activity between 2004 and 2014. Among the specimens examined, we identified the following mutations: 33 missense, 8 nonsense, 7 frameshift, 4 intronic changes affecting splicing, 8 recombinations involving IDS-IDS2, and 7 other mutations including 4 large deletions. Consistent with the previous data, the results of our study showed that most of the attenuated phenotype was derived from the missense mutations of the IDS gene, whereas mutations associated with a large structural alteration including recombination, splicing, frameshift, and nonsense mutations were linked to the severe phenotype of MPS II. Furthermore, we conducted a homology modeling study of IDS P120R and N534I mutant as representatives of the causative mutation of the severe and attenuated type of MPS II, respectively. We found that the substitution of P120R of the IDS enzyme was predicted to deform the α-helix generated by I119-F123, leading to the major structural alteration of the wild-type IDS enzyme. In sharp contrast, the effect of the structural alteration of N534I was marginal; thus, this mutation was pathogenically predicted to be associated with the attenuated type of MPS II. These results suggest that a combination of the genomic diagnosis of the IDS gene and the structural prediction of the IDS enzyme could enable the prediction of a phenotype more effectively.
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Affiliation(s)
- Motomichi Kosuga
- Center for Lysosomal Storage Diseases, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan; Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan; Division of Medical Genetics, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan.
| | - Ryuichi Mashima
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan.
| | - Asami Hirakiyama
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Naoko Fuji
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Tadayuki Kumagai
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Joo-Hyun Seo
- Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Mari Nikaido
- Biobank, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
| | - Seiji Saito
- Department of Medical Management and Informatics, Hokkaido Information University, 59-2 Nishinopporo, Ebetsu, Hokkaido 069-8585, Japan
| | - Kazuki Ohno
- Catalyst Inc., 1-5-6 Kudan-minami, Chiyoda-ku, Tokyo 102-0074, Japan
| | - Hitoshi Sakuraba
- Department of Clinical Genetics, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan
| | - Torayuki Okuyama
- Center for Lysosomal Storage Diseases, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan; Department of Clinical Laboratory Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo 157-8535, Japan
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16
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Chistiakov DA, Kuzenkova LM, Savost'anov KV, Gevorkyan AK, Pushkov AA, Nikitin AG, Vashakmadze ND, Zhurkova NV, Podkletnova TV, Namazova-Baranova LS, Baranov AA. Genetic analysis of 17 children with Hunter syndrome: identification and functional characterization of four novel mutations in the iduronate-2-sulfatase gene. J Genet Genomics 2014; 41:197-203. [PMID: 24780617 DOI: 10.1016/j.jgg.2014.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 01/21/2014] [Accepted: 01/26/2014] [Indexed: 10/25/2022]
Abstract
Mucopolysaccharidosis type II (MPS II) is a rare X-linked disorder caused by alterations in the iduronate-2-sulfatase (IDS) gene. In this study, IDS activity in peripheral mononuclear blood monocytes (PMBCs) was measured with a fluorimetric enzyme assay. Urinary glycosaminoglycans (GAGs) were quantified using a colorimetric assay. All IDS exons and intronic flanks were bidirectionally sequenced. A total of 15 mutations (all exonic region) were found in 17 MPS II patients. In this cohort of MPS II patients, all alterations in the IDS gene were caused by point nucleotide substitutions or small deletions. Mutations p.Arg88His and p.Arg172* occurred twice. All mutations were inherited except for p.Gly489Alafs*7, a germline mutation. We found four new mutations (p.Ser142Phe, p.Arg233Gly, p.Glu430*, and p.Ile360Tyrfs*31). In Epstein-Barr virus (EBV)-immortalized PMBCs derived from the MPS II patients, no IDS protein was detected in case of the p.Ser142Phe and p.Ile360Tyrfs*31 mutants. For p.Arg233Gly and p.Glu430*, we observed a residual expression of IDS. The p.Arg233Gly and p.Glu430* mutants had a residuary enzymatic activity that was lowered by 14.3 and 76-fold, respectively, compared with healthy controls. This observation may help explain the mild disease phenotype in MPS II patients who had these two mutations whereas the p.Ser142Phe and p.Ile360Tyrfs*31 mutations caused the severe disease manifestation.
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Affiliation(s)
- Dimitry A Chistiakov
- Department of Medical Nanobiotechnology, Pirogov Russian State Medical University, Moscow 117997, Russia; Department of Molecular and Genetic Diagnostics, Division of Laboratory Medicine, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia.
| | - Lyudmila M Kuzenkova
- Department of Psychoneurology and Psychosomatic Pathology, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia
| | - Kirill V Savost'anov
- Department of Molecular and Genetic Diagnostics, Division of Laboratory Medicine, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia
| | - Anait K Gevorkyan
- Institute of Preventive Pediatrics and Rehabilitation, Research Center for Children's Health, Moscow 119991, Russia
| | - Alexander A Pushkov
- Department of Molecular and Genetic Diagnostics, Division of Laboratory Medicine, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia
| | - Alexey G Nikitin
- Department of Molecular and Genetic Diagnostics, Division of Laboratory Medicine, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia
| | - Nato D Vashakmadze
- Department of Psychoneurology and Psychosomatic Pathology, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia
| | - Natalia V Zhurkova
- Department of Molecular and Genetic Diagnostics, Division of Laboratory Medicine, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia
| | - Tatiana V Podkletnova
- Department of Psychoneurology and Psychosomatic Pathology, Institute of Pediatrics, Research Center for Children's Health, Moscow 119991, Russia
| | - Leila S Namazova-Baranova
- Institute of Preventive Pediatrics and Rehabilitation, Research Center for Children's Health, Moscow 119991, Russia
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17
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Brusius-Facchin AC, Schwartz IVD, Zimmer C, Ribeiro MG, Acosta AX, Horovitz D, Monlleó IL, Fontes MIB, Fett-Conte A, Sobrinho RPO, Duarte AR, Boy R, Mabe P, Ascurra M, de Michelena M, Tylee KL, Besley GTN, Garreton MCV, Giugliani R, Leistner-Segal S. Mucopolysaccharidosis type II: identification of 30 novel mutations among Latin American patients. Mol Genet Metab 2014; 111:133-8. [PMID: 24125893 DOI: 10.1016/j.ymgme.2013.08.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
Abstract
In this study, 103 unrelated South-American patients with mucopolysaccharidosis type II (MPS II) were investigated aiming at the identification of iduronate-2-sulfatase (IDS) disease causing mutations and the possibility of some insights on the genotype-phenotype correlation The strategy used for genotyping involved the identification of the previously reported inversion/disruption of the IDS gene by PCR and screening for other mutations by PCR/SSCP. The exons with altered mobility on SSCP were sequenced, as well as all the exons of patients with no SSCP alteration. By using this strategy, we were able to find the pathogenic mutation in all patients. Alterations such as inversion/disruption and partial/total deletions of the IDS gene were found in 20/103 (19%) patients. Small insertions/deletions/indels (<22 bp) and point mutations were identified in 83/103 (88%) patients, including 30 novel mutations; except for a higher frequency of small duplications in relation to small deletions, the frequencies of major and minor alterations found in our sample are in accordance with those described in the literature.
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Affiliation(s)
| | - I V D Schwartz
- Post Graduation Program in Medical Sciences, UFRGS, Porto Alegre, RS, Brazil; Department of Genetics, UFRGS, Porto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Brazil
| | - C Zimmer
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Brazil
| | - M G Ribeiro
- Clinical Genetics Service, IPPMG, UFRJ, Rio de Janeiro, Brazil
| | - A X Acosta
- Department of Pediatrics, UFBA, Salvador, Brazil
| | - D Horovitz
- Instituto Fernandes Figueira, FIOCRUZ, Rio de Janeiro, Brazil
| | - I L Monlleó
- Department of Pediatrics, UNCISAL, Maceió, Brazil
| | - M I B Fontes
- Department of Pediatrics, UNCISAL, Maceió, Brazil
| | - A Fett-Conte
- Department of Molecular Biology, FAMERP, São José do Rio Preto, Brazil
| | | | - A R Duarte
- Medical Genetics Service, IMIP, Recife, Brazil
| | - R Boy
- Mother and Child Department, UERJ, Rio de Janeiro, Brazil
| | - P Mabe
- Genetics and Metabolic Diseases Unit, INTA, University of Chile, Chile
| | - M Ascurra
- Department of Genetics, ILCS-UNA, Asunción, Paraguay
| | | | - K L Tylee
- Willink Biochemical Genetics Unit, Royal Manchester Children's Hospital, Manchester, UK
| | - G T N Besley
- Willink Biochemical Genetics Unit, Royal Manchester Children's Hospital, Manchester, UK
| | - M C V Garreton
- Unidad de Genética Clínica, Hospital Roberto del Río, Santiago, Chile
| | - R Giugliani
- Post Graduation Program in Medical Sciences, UFRGS, Porto Alegre, RS, Brazil; Department of Genetics, UFRGS, Porto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Brazil
| | - S Leistner-Segal
- Post Graduation Program in Medical Sciences, UFRGS, Porto Alegre, RS, Brazil; Department of Genetics, UFRGS, Porto Alegre, Brazil; Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Brazil.
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18
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Decreasing activity and altered protein processing of human iduronate-2-sulfatase mutations demonstrated by expression in COS7 cells. Biochem Genet 2012; 50:990-7. [PMID: 22990955 DOI: 10.1007/s10528-012-9538-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 06/13/2012] [Indexed: 10/27/2022]
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19
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Zhang H, Li J, Zhang X, Wang Y, Qiu W, Ye J, Han L, Gao X, Gu X. Analysis of the IDS gene in 38 patients with Hunter syndrome: the c.879G>A (p.Gln293Gln) synonymous variation in a female create exonic splicing. PLoS One 2011; 6:e22951. [PMID: 21829674 PMCID: PMC3150403 DOI: 10.1371/journal.pone.0022951] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 07/01/2011] [Indexed: 11/18/2022] Open
Abstract
Background Hunter syndrome (mucopolysaccharidosis type II, MPS II) is a rare disease inherited in an X-linked autosomal recessive pattern. It is the prevailing form of the mucopolysaccharidoses in China. Here we investigated mutations of IDS (iduronate 2-sulfatase) gene in 38 unrelated Chinese patients, one of which is a female. Methods Peripheral leucocytes were collected from the patients and the IDS gene was amplified to looking for the variations. For a female patient, the X chromosome status was analyzed by androgen receptor X-inactivation assay and the mutation impact on RNA level was further performed by reverse transcription polymerase chain reaction. Results We discovered that point mutations constituted the major form while mutations in codon p.R468 defined the largest number of patients in our cohort. Consistent with data from other ethnic groups, exons 9 and 3 had comparatively more mutations, while exon 2 had quite a few mutations unique to Chinese patients. Of the 30 different mutations identified, only 9 were novel: one was a premature termination mutation, i.e., c.196C>T (p.Gln66X); three were missense mutations, i.e., c.200T>C (p.Leu67Pro), c.215T>C (p.Leu72Pro), c.389C>T (p.Thr130Ile); one was a small deletion, i.e., c.1104_1122del19 (p.Ser369ArgfsX16); and one was a deletion that spanned both exons 8 and 9 deletion leading to gross structural changes in the IDS gene. In addition, a synonymous mutation c.879G>A (p.Gln293Gln) was identified in a female Hunter disease patient, which resulted in loss of the original splicing site, activated a cryptic splicing site upstream, leading to a 28 bp deletion and a premature termination at p. Tyr285GlufsX47. Together with concurrent skewed X-inactivation this was believed to facilitate the development of Hunter disease in this girl. Conclusions In conclusion, the molecular analysis of IDS gene in Chinese patients confirmed the Hunter disease diagnosis and expanded the mutation and clinical spectrum of this devastating disorder.
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Affiliation(s)
- Huiwen Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (HZ); (XG)
| | - Jing Li
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xinshun Zhang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yu Wang
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenjuan Qiu
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Ye
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lianshu Han
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaolan Gao
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xuefan Gu
- Department of Pediatric Endocrinology and Genetic Metabolism, Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (HZ); (XG)
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