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Uribe-Carretero E, Rey V, Fuentes JM, Tamargo-Gómez I. Lysosomal Dysfunction: Connecting the Dots in the Landscape of Human Diseases. BIOLOGY 2024; 13:34. [PMID: 38248465 PMCID: PMC10813815 DOI: 10.3390/biology13010034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/22/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024]
Abstract
Lysosomes are the main organelles responsible for the degradation of macromolecules in eukaryotic cells. Beyond their fundamental role in degradation, lysosomes are involved in different physiological processes such as autophagy, nutrient sensing, and intracellular signaling. In some circumstances, lysosomal abnormalities underlie several human pathologies with different etiologies known as known as lysosomal storage disorders (LSDs). These disorders can result from deficiencies in primary lysosomal enzymes, dysfunction of lysosomal enzyme activators, alterations in modifiers that impact lysosomal function, or changes in membrane-associated proteins, among other factors. The clinical phenotype observed in affected patients hinges on the type and location of the accumulating substrate, influenced by genetic mutations and residual enzyme activity. In this context, the scientific community is dedicated to exploring potential therapeutic approaches, striving not only to extend lifespan but also to enhance the overall quality of life for individuals afflicted with LSDs. This review provides insights into lysosomal dysfunction from a molecular perspective, particularly in the context of human diseases, and highlights recent advancements and breakthroughs in this field.
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Affiliation(s)
- Elisabet Uribe-Carretero
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Caceres, Spain; (E.U.-C.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salud Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Caceres, Spain
| | - Verónica Rey
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Jose Manuel Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Caceres, Spain; (E.U.-C.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salud Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto Universitario de Investigación Biosanitaria de Extremadura (INUBE), 10003 Caceres, Spain
| | - Isaac Tamargo-Gómez
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
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Kim MS, Yang A, Noh ES, Kim C, Bae GY, Lim HH, Park HD, Cho SY, Jin DK. Natural History and Molecular Characteristics of Korean Patients with Mucopolysaccharidosis Type III. J Pers Med 2022; 12:jpm12050665. [PMID: 35629088 PMCID: PMC9145712 DOI: 10.3390/jpm12050665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/18/2022] [Accepted: 04/19/2022] [Indexed: 02/05/2023] Open
Abstract
Background: Mucopolysaccharidosis type III (MPS III) is an autosomal recessive lysosomal storage disorder characterised by progressive neurocognitive deterioration. MPS III subtypes are clinically indistinguishable, with a wide range of symptoms and variable severity. The natural history of this disorder within an Asian population has not yet been extensively studied. This study investigated the natural history of Korean patients with MPS III. Methods: Thirty-four patients from 31 families diagnosed with MPS III from January 1997 to May 2020 in Samsung Medical Centre were enrolled. Clinical, molecular, and biochemical characteristics were retrospectively collected from the patients’ medical records and via interviews. Results: 18 patients had MPS IIIA, 14 had IIIB, and two had IIIC. Twenty (58.9%) patients were male. Mean age at symptom onset was 2.8 ± 0.8 years and at diagnosis was 6.3 ± 2.2 years. All patients with MPS IIIA and IIIB were classified into the rapidly progressing (RP) phenotype. The most common symptom at diagnosis was language retardation (88.2%), followed by motor retardation (76.5%), general retardation (64.7%), and hyperactivity (41.2%). Language retardation was more predominant in IIIA, and motor retardation was more predominant in IIIB. The mean age of the 13 deceased patients at the time of the study was 14.4 ± 4.1 years. The age at diagnosis and lag time were significantly older and longer in the non-survivor group compared with the survivor group (p = 0.029 and 0.045, respectively). Genetic analysis was performed in 24 patients with MPS III and identified seven novel variants and three hot spots. Conclusion: This study is the first to analyse the genetic and clinical characteristics of MPS III patients in Korea. Better understanding of the natural history of MPS III might allow early diagnosis and timely management of the disease and evaluation of treatment outcomes in future clinical trials for MPS III.
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Affiliation(s)
- Min-Sun Kim
- Department of Pediatrics, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul 06351, Korea; (M.-S.K.); (E.-s.N.); (G.Y.B.); (D.-K.J.)
| | - Aram Yang
- Department of Pediatrics, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 03181, Korea;
| | - Eu-seon Noh
- Department of Pediatrics, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul 06351, Korea; (M.-S.K.); (E.-s.N.); (G.Y.B.); (D.-K.J.)
| | - Chiwoo Kim
- Department of Pediatrics, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Korea;
| | - Ga Young Bae
- Department of Pediatrics, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul 06351, Korea; (M.-S.K.); (E.-s.N.); (G.Y.B.); (D.-K.J.)
| | - Han Hyuk Lim
- Department of Pediatrics, Chungnam National University College of Medicine, Daejeon 35015, Korea;
| | - Hyung-Doo Park
- Department of Laboratory Medicine and Genetics, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul 06351, Korea;
| | - Sung Yoon Cho
- Department of Pediatrics, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul 06351, Korea; (M.-S.K.); (E.-s.N.); (G.Y.B.); (D.-K.J.)
- Correspondence: ; Tel.: +82-2-3410-3539; Fax: +82-2-3410-0043
| | - Dong-Kyu Jin
- Department of Pediatrics, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul 06351, Korea; (M.-S.K.); (E.-s.N.); (G.Y.B.); (D.-K.J.)
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Wijburg FA, Aiach K, Chakrapani A, Eisengart JB, Giugliani R, Héron B, Muschol N, O'Neill C, Olivier S, Parker S. An observational, prospective, multicenter, natural history study of patients with mucopolysaccharidosis type IIIA. Mol Genet Metab 2022; 135:133-142. [PMID: 34991944 DOI: 10.1016/j.ymgme.2021.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/04/2021] [Accepted: 12/05/2021] [Indexed: 10/19/2022]
Abstract
Mucopolysaccharidosis type IIIA (MPS IIIA, also known as Sanfilippo syndrome) is a rare genetic lysosomal storage disease characterized by early and progressive neurodegeneration resulting in a rapid decline in cognitive function affecting speech and language, adaptive behavior, and motor skills. We carried out a prospective observational study to assess the natural history of patients with MPS IIIA, using both standardized tests and patient-centric measures to determine the course of disease progression over a 2-year period. A cohort of 23 patients (7 girls, 16 boys; mean age 28-105 months at baseline) with a confirmed diagnosis of MPS IIIA were assessed and followed up at intervals of 3-6 months; cognitive function was measured using Bayley Scales of Infant and Toddler Development 3rd edition (BSID-III) to derive cognitive development quotients (DQ). Daily living, speech/language development and motor skills were measured using the Vineland Adaptive Behavior Scale (VABS-II). Sleep-wake patterns, behavior and quality-of-life questionnaires were also reported at each visit using parent/caregiver reported outcome tools. All patients had early onset severe MPS IIIA, were diagnosed before 74 months of age, and had cognitive scores below normal developmental levels at baseline. Patients less than 40 months of age at baseline were more likely to continue developing new skills over the first 6-12 months of follow-up. There was a high variability in cognitive developmental age (DA) in patients between 40 and 70 months of age; two-thirds of these patients already had profound cognitive decline, with a DA ≤10 months. The highest cognitive DA achieved in the full study cohort was 34 months. Post hoc, patients were divided into two groups based on baseline cognitive DQ (DQ ≥50 or <50). Cognitive DQ decreased linearly over time, with a decrease from baseline of 30.1 and 9.0 points in patients with cognitive DQ ≥50 at baseline and cognitive DQ <50 at baseline, respectively. Over the 2-year study, VABS-II language scores declined progressively. Motor skills, including walking, declined over time, although significantly later than cognitive decline. No clear pattern of sleep disturbance was observed, but night waking was common in younger patients. Pain scores, as measured on the quality-of-life questionnaire, increased over the study period. The findings of this study strengthen the natural history data on cognitive decline in MPS IIIA and importantly provide additional data on endpoints, validated by the patient community as important to treat, that may form the basis of a multidomain endpoint capturing the disease complexity.
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Affiliation(s)
- Frits A Wijburg
- Department of Pediatric Metabolic Diseases, Emma Children's Hospital, Amsterdam UMC, Amsterdam, Netherlands; Amsterdam Lysosome Center "Sphinx", University of Amsterdam, Amsterdam, Netherlands.
| | | | - Anupam Chakrapani
- Metabolic Medicine Department, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, UK
| | - Julie B Eisengart
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Roberto Giugliani
- Department of Genetics, UFRGS, Medical Genetics Service and DR Brazil, HCPA, Porto Alegre, Brazil
| | - Bénédicte Héron
- Reference Center for Lysosomal Diseases, Pediatric Neurology Department, Armand Trousseau University Hospital, APHP, Paris, France
| | - Nicole Muschol
- Department of Pediatrics, International Center for Lysosomal Disorders (ICLD), University Medical Center Hamburg Eppendorf, Hamburg, Germany
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Shapiro EG, Eisengart JB. The natural history of neurocognition in MPS disorders: A review. Mol Genet Metab 2021; 133:8-34. [PMID: 33741271 DOI: 10.1016/j.ymgme.2021.03.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 01/22/2023]
Abstract
MPS disorders are associated with a wide spectrum of neurocognitive effects, from mild problems with attention and executive functions to progressive and degenerative neuronopathic disease. Studies of the natural history of neurocognition are necessary to determine the profile of abnormality and the rates of change, which are crucial to select endpoints for clinical trials of brain treatments and to make clinical recommendations for interventions to improve patients' quality of life. The goal of this paper is to review neurocognitive natural history studies to determine the current state of knowledge and assist in directing future research in all MPS disorders. There are seven different types of MPS diseases, each resulting from a specific enzyme deficiency and each having a separate natural history. MPS IX, will not be discussed as there are only 4 cases reported in the literature without cognitive abnormality. For MPS IH, hematopoietic cell transplant (HCT) is standard of care and many studies have documented the relationship between age at treatment and neurocognitive outcome, and to a lesser extent, neurocognitive status at baseline. However, the mortality and morbidity associated with the transplant process and residual long-term problems after transplant, have led to renewed efforts to find better treatments. Rather than natural history, new trials will likely need to use the developmental trajectories of the patients with HCT as a comparators. The literature has extensive data regarding developmental trajectories post-HCT. For attenuated MPS I, significant neurocognitive deficits have been documented, but more longitudinal data are needed in order to support a treatment directed at their attention and executive function abnormalities. The neuronopathic form of MPS II has been a challenge due to the variability of the trajectory of the disease with differences in timing of slowing of development and decline. Finding predictors of the course of the disease has only been partially successful, using mutation type and family history. Because of lack of systematic data and clinical trials that precede a thorough understanding of the disease, there is need for a major effort to gather natural history data on the entire spectrum of MPS II. Even in the attenuated disease, attention and executive function abnormalities need documentation. Lengthy detailed longitudinal studies are needed to encompass the wide variability in MPS II. In MPS IIIA, the existence of three good natural history studies allowed a quasi-meta-analysis. In patients with a rapid form of the disease, neurocognitive development slowed up until 42 to 47 months, halted up to about 54 months, then declined rapidly thereafter, with a leveling off at an extremely low age equivalent score below 22 months starting at about chronological age of 6. Those with slower or attenuated forms have been more variable and difficult to characterize. Because of the plethora of studies in IIIA, it has been recommended that data be combined from natural history studies to minimize the burden on parents and patients. Sufficient data exists to understand the natural history of cognition in MPS IIIA. MPS IIIB is quite similar to IIIA, but more attenuated patients in that phenotype have been reported. MPS IIIC and D, because they are so rare, have little documentation of natural history despite the prospects of treatments. MPS IV and VI are the least well documented of the MPS disorders with respect to their neurocognitive natural history. Because, like attenuated MPS I and II, they do not show progression of neurocognitive abnormality and most patients function in the range of normality, their behavioral, attentional, and executive function abnormalities have been ignored to the detriment of their quality of life. A peripheral treatment for MPS VII, extremely rare even among MPS types, has recently been approved with a post-approval monitoring system to provide neurocognitive natural history data in the future. More natural history studies in the MPS forms with milder cognitive deficits (MPS I, II, IV, and VI) are recommended with the goal of improving these patients' quality of life with and without new brain treatments, beyond the benefits of available peripheral enzyme replacement therapy. Recommendations are offered at-a-glance with respect to what areas most urgently need attention to clarify neurocognitive function in all MPS types.
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Affiliation(s)
- Elsa G Shapiro
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA; Shapiro Neuropsychology Consulting LLC, Portland, OR, USA.
| | - Julie B Eisengart
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
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Epidemiology of Mucopolysaccharidoses Update. Diagnostics (Basel) 2021; 11:diagnostics11020273. [PMID: 33578874 PMCID: PMC7916572 DOI: 10.3390/diagnostics11020273] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 12/26/2022] Open
Abstract
Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by a lysosomal enzyme deficiency or malfunction, which leads to the accumulation of glycosaminoglycans in tissues and organs. If not treated at an early stage, patients have various health problems, affecting their quality of life and life-span. Two therapeutic options for MPS are widely used in practice: enzyme replacement therapy and hematopoietic stem cell transplantation. However, early diagnosis of MPS is crucial, as treatment may be too late to reverse or ameliorate the disease progress. It has been noted that the prevalence of MPS and each subtype varies based on geographic regions and/or ethnic background. Each type of MPS is caused by a wide range of the mutational spectrum, mainly missense mutations. Some mutations were derived from the common founder effect. In the previous study, Khan et al. 2018 have reported the epidemiology of MPS from 22 countries and 16 regions. In this study, we aimed to update the prevalence of MPS across the world. We have collected and investigated 189 publications related to the prevalence of MPS via PubMed as of December 2020. In total, data from 33 countries and 23 regions were compiled and analyzed. Saudi Arabia provided the highest frequency of overall MPS because of regional or consanguineous marriages (or founder effect), followed by Portugal, Brazil, the Netherlands, and Australia. The newborn screening is an efficient and early diagnosis for MPS. MPS I has been approved for newborn screening in the United States. After the newborn screening of MPS I, the frequency of MPS I increased, compared with the past incidence rates. Overall, we conclude that the current identification methods are not enough to recognize all MPS patients, leading to an inaccurate incidence and status. Differences in ethnic background and/or founder effects impact on the frequency of MPS, which affects the prevalence of MPS. Two-tier newborn screening has accelerated early recognition of MPS I, providing an accurate incidence of patients.
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Filocamo M, Tomanin R, Bertola F, Morrone A. Biochemical and molecular analysis in mucopolysaccharidoses: what a paediatrician must know. Ital J Pediatr 2018; 44:129. [PMID: 30442161 PMCID: PMC6238298 DOI: 10.1186/s13052-018-0553-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mucopolysaccharidoses (MPS) are rare inherited disorders caused by a deficit of the lysosomal hydrolases involved in the degradation of mucopolysaccharides, also known as glycosaminoglycans (GAGs). They are all monogenic defects, transmitted in an autosomal recessive way, except for MPS type II which is X-linked. The enzymatic deficit causes a pathologic accumulation of undegraded or partially degraded substrates inside lysosomes as well as in the extracellular compartment. MPS generally present with recognizable signs and symptoms to raise a clinical suspicion. However, although they have individual peculiarities, often signs and symptoms may overlap between different MPS types. Therefore, a deeper evaluation of specific disease biomarkers becomes necessary to reach an appropriate diagnosis. This paper stresses the central role of the laboratory in completing and confirming the clinical suspicion of MPS according to a standardized procedure: first, a biochemical evaluation of the patient samples, including qualitative/quantitative urinary GAG analysis and a determination of enzyme activities, and then the molecular diagnosis. We also encourage a constant and close communication between clinicians and laboratory personnel to address a correct and early MPS diagnosis.
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Affiliation(s)
- Mirella Filocamo
- Laboratorio di Genetica Molecolare e Biobanche, Istituto G. Gaslini, Genova, Italy
| | - Rosella Tomanin
- Laboratory of Diagnosis and Therapy of Lysosomal Disorders, Department of Women’s and Children’s Health, University of Padova, Padova, Italy
| | - Francesca Bertola
- School of Medicine and Surgery, University of Milano Bicocca, Monza, Italy
| | - Amelia Morrone
- Neuroscience Department, Molecular and Cell Biology Laboratory of Neurometabolic Diseases, Meyer Children’s Hospital, University of Florence, Florence, Italy
- Department of Neurofarba, University of Florence, Florence, Italy
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Khan SA, Peracha H, Ballhausen D, Wiesbauer A, Rohrbach M, Gautschi M, Mason RW, Giugliani R, Suzuki Y, Orii KE, Orii T, Tomatsu S. Epidemiology of mucopolysaccharidoses. Mol Genet Metab 2017; 121:227-240. [PMID: 28595941 PMCID: PMC5653283 DOI: 10.1016/j.ymgme.2017.05.016] [Citation(s) in RCA: 158] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/22/2017] [Accepted: 05/22/2017] [Indexed: 12/15/2022]
Abstract
The aim of this study was to obtain data about the epidemiology of the different types of mucopolysaccharidoses in Japan and Switzerland and to compare with similar data from other countries. Data for Japan was collected between 1982 and 2009, and 467 cases with MPS were identified. The combined birth prevalence was 1.53 per 100,000 live births. The highest birth prevalence was 0.84 for MPS II, accounting for 55% of all MPS. MPS I, III, and IV accounted for 15, 16, and 10%, respectively. MPS VI and VII were more rare and accounted for 1.7 and 1.3%, respectively. A retrospective epidemiological data collection was performed in Switzerland between 1975 and 2008 (34years), and 41 living MPS patients were identified. The combined birth prevalence was 1.56 per 100,000 live births. The highest birth prevalence was 0.46 for MPS II, accounting for 29% of all MPS. MPS I, III, and IV accounted for 12, 24, and 24%, respectively. As seen in the Japanese population, MPS VI and VII were more rare and accounted for 7.3 and 2.4%, respectively. The high birth prevalence of MPS II in Japan was comparable to that seen in other East Asian countries where this MPS accounted for approximately 50% of all forms of MPS. Birth prevalence was also similar in some European countries (Germany, Northern Ireland, Portugal and the Netherlands) although the prevalence of other forms of MPS is also reported to be higher in these countries. Birth prevalence of MPS II in Switzerland and other European countries is comparatively lower. The birth prevalence of MPS III and IV in Switzerland is higher than in Japan but comparable to that in most other European countries. Moreover, the birth prevalence of MPS VI and VII was very low in both, Switzerland and Japan. Overall, the frequency of MPS varies for each population due to differences in ethnic backgrounds and/or founder effects that affect the birth prevalence of each type of MPS, as seen for other rare genetic diseases. Methods for identification of MPS patients are not uniform across all countries, and consequently, if patients are not identified, recorded prevalence rates will be aberrantly low.
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Affiliation(s)
- Shaukat A Khan
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Hira Peracha
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Diana Ballhausen
- Centre for Molecular Diseases, Service for Genetic Medicine, University Hospital Lausanne, Switzerland
| | - Alfred Wiesbauer
- Institute of Social and Preventive Medicine, University of Bern, Switzerland
| | - Marianne Rohrbach
- Division of Metabolism and Children's Research Centre (CRC), University Children's Hospital, Zurich, Switzerland
| | - Matthias Gautschi
- Division of Endocrinology, Diabetology and Metabolism, University Children's Hospital, University Institute of Clinical Chemistry, Inselspital, University of Bern, Bern, Switzerland
| | - Robert W Mason
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Roberto Giugliani
- Medical Genetics Service, HCPA, Dep. Genetics, UFRGS, and INAGEMP, Porto Alegre, Brazil
| | | | - Kenji E Orii
- Department of Pediatrics, Gifu University, Gifu, Japan
| | - Tadao Orii
- Department of Pediatrics, Gifu University, Gifu, Japan
| | - Shunji Tomatsu
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States; Department of Pediatrics, Gifu University, Gifu, Japan; Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA, United States.
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Shapiro EG, Nestrasil I, Delaney KA, Rudser K, Kovac V, Nair N, Richard CW, Haslett P, Whitley CB. A Prospective Natural History Study of Mucopolysaccharidosis Type IIIA. J Pediatr 2016; 170:278-87.e1-4. [PMID: 26787381 PMCID: PMC4769976 DOI: 10.1016/j.jpeds.2015.11.079] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/09/2015] [Accepted: 11/30/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVES To characterize the clinical course of mucopolysaccharidosis type IIIA (MPS IIIA), and identify potential endpoints for future treatment trials. STUDY DESIGN Children with a confirmed diagnosis of MPS IIIA, functioning above a developmental age of 1 year, were followed for up to 2 years. Cognitive status and brain atrophy were assessed by standardized tests and volumetric magnetic resonance imaging, respectively. Liver and spleen volumes and cerebrospinal fluid and urine biomarker levels were measured. RESULTS Twenty-five children, from 1.1 to 18.4 years old, were enrolled, and 24 followed for at least 12 months. 19 exhibited a rapidly progressing (RP) form of MPS IIIA, and 5, a more slowly progressing form. Children with RP plateaued in development by 30 months, followed by rapid regression after 40-50 months. In patients with RP, cognitive developmental quotients showed consistent steep declines associated with progressive cortical gray matter atrophy. Children with slowly progressing had a similar but more prolonged course. Liver and spleen volumes were approximately double normal size, and cerebrospinal fluid and urine heparin sulfate levels were elevated and relatively constant over time. CONCLUSION Developmental quotient and cortical gray matter volume are sensitive markers of disease progression in MPS IIIA, and may have utility as clinical endpoints in treatment trials. For optimal outcomes, treatment may need to be instituted in children before the onset of steep cognitive decline and brain atrophy. TRIAL REGISTRATION ClinicalTrials.gov: NCT01047306.
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Affiliation(s)
- Elsa G Shapiro
- Department of Pediatrics, University of Minnesota, Minneapolis, MN.
| | - Igor Nestrasil
- Department of Pediatrics, University of Minnesota, Minneapolis, MN
| | | | - Kyle Rudser
- Division of Biostatistics, University of Minnesota, Minneapolis, MN
| | - Victor Kovac
- Department of Pediatrics, University of Minnesota, Minneapolis, MN
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Bodamer OA, Giugliani R, Wood T. The laboratory diagnosis of mucopolysaccharidosis III (Sanfilippo syndrome): A changing landscape. Mol Genet Metab 2014; 113:34-41. [PMID: 25127543 DOI: 10.1016/j.ymgme.2014.07.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 07/11/2014] [Accepted: 07/11/2014] [Indexed: 12/24/2022]
Abstract
Mucopolysaccharidosis type III (MPS III) is characterized by progressive neurological deterioration, behavioral abnormalities, a relatively mild somatic phenotype, and early mortality. Because of the paucity of somatic manifestations and the rarity of the disease, early diagnosis is often difficult. Therapy targeting the underlying disease pathophysiology may offer the greatest clinical benefit when started prior to the onset of significant neurologic sequelae. Here we review current practices in the laboratory diagnosis of MPS III in order to facilitate earlier patient identification and diagnosis. When clinical suspicion of MPS III arises, the first step is to order a quantitative assay that screens urine for the presence of glycosaminoglycan biomarkers using a spectrophotometric compound (e.g., dimethylmethylene blue). We recommend testing all patients with developmental delay and/or behavioral abnormalities as part of the diagnostic work-up because quantitative urine screening is inexpensive and non-invasive. Semi-quantitative urine screening assays using cationic dyes on filter paper (e.g., spot tests) have relatively high rates of false-positives and false-negatives and are obsolete. Of note, a negative urinary glycosaminoglycan assay does not necessarily rule out MPS because, in some patients, an overlap in excretion levels with healthy controls may occur. All urine samples that test positive for glycosaminoglycans with a quantitative assay should be confirmed by electrophoresis, thin layer chromatography, or tandem mass spectrometry, which further improves the sensitivity and specificity. The gold standard for diagnosis remains the enzyme activity assay in cultured skin fibroblasts, leukocytes, plasma, or serum, which can be used as a first-line diagnostic test in some regions. Molecular genetic analysis should be offered to all families of patients to allow genetic counseling for informed family planning. For a small number of variants, genotype-phenotype correlations are available and can offer prognostic value. Prenatal testing via enzyme activity assay in chorionic villi or amniotic fluid cells is available at a limited number of centers worldwide, but whenever possible, a molecular genetic analysis is preferred for prenatal diagnosis. To conclude, we discuss the development of newborn screening assays in dried blood spots and high-throughput methods for sequencing the protein-coding regions of the genome (whole exome sequencing) and their relevance to future changes in the MPS III diagnostic landscape.
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Affiliation(s)
- Olaf A Bodamer
- Division of Clinical and Translational Genetics, Dr. John T. MacDonald Foundation, Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Roberto Giugliani
- Department of Genetics/UFRGS, Medical Genetics Service/HCPA and INAGEMP, Porto Alegre, RS, Brazil
| | - Tim Wood
- Metabolic Laboratory, Greenwood Genetic Center, Greenwood, SC, USA.
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Sidhu NS, Schreiber K, Pröpper K, Becker S, Usón I, Sheldrick GM, Gärtner J, Krätzner R, Steinfeld R. Structure of sulfamidase provides insight into the molecular pathology of mucopolysaccharidosis IIIA. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:1321-35. [PMID: 24816101 PMCID: PMC4014121 DOI: 10.1107/s1399004714002739] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 02/05/2014] [Indexed: 11/10/2022]
Abstract
Mucopolysaccharidosis type IIIA (Sanfilippo A syndrome), a fatal childhood-onset neurodegenerative disease with mild facial, visceral and skeletal abnormalities, is caused by an inherited deficiency of the enzyme N-sulfoglucosamine sulfohydrolase (SGSH; sulfamidase). More than 100 mutations in the SGSH gene have been found to reduce or eliminate its enzymatic activity. However, the molecular understanding of the effect of these mutations has been confined by a lack of structural data for this enzyme. Here, the crystal structure of glycosylated SGSH is presented at 2 Å resolution. Despite the low sequence identity between this unique N-sulfatase and the group of O-sulfatases, they share a similar overall fold and active-site architecture, including a catalytic formylglycine, a divalent metal-binding site and a sulfate-binding site. However, a highly conserved lysine in O-sulfatases is replaced in SGSH by an arginine (Arg282) that is positioned to bind the N-linked sulfate substrate. The structure also provides insight into the diverse effects of pathogenic mutations on SGSH function in mucopolysaccharidosis type IIIA and convincing evidence for the molecular consequences of many missense mutations. Further, the molecular characterization of SGSH mutations will lay the groundwork for the development of structure-based drug design for this devastating neurodegenerative disorder.
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Affiliation(s)
- Navdeep S. Sidhu
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
- Department of Structural Chemistry, Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Kathrin Schreiber
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
| | - Kevin Pröpper
- Department of Structural Chemistry, Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Stefan Becker
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Isabel Usón
- Instituto de Biologia Molecular de Barcelona (IBMB–CSIC), Barcelona Science Park, Baldiri Reixach 15, 08028 Barcelona, Spain
- Institucio Catalana de Recerca i Estudis Avancats (ICREA), Spain
| | - George M. Sheldrick
- Department of Structural Chemistry, Institute of Inorganic Chemistry, University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
| | - Jutta Gärtner
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
| | - Ralph Krätzner
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
| | - Robert Steinfeld
- Department of Neuropediatrics, Faculty of Medicine, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany
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11
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Muschol N, Pohl S, Meyer A, Gal A, Ullrich K, Braulke T. Residual activity and proteasomal degradation of p.Ser298Pro sulfamidase identified in patients with a mild clinical phenotype of Sanfilippo A syndrome. Am J Med Genet A 2011; 155A:1634-9. [DOI: 10.1002/ajmg.a.34053] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 03/24/2011] [Indexed: 11/06/2022]
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12
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Valstar MJ, Neijs S, Bruggenwirth HT, Olmer R, Ruijter GJG, Wevers RA, van Diggelen OP, Poorthuis BJ, Halley DJ, Wijburg FA. Mucopolysaccharidosis type IIIA: clinical spectrum and genotype-phenotype correlations. Ann Neurol 2011; 68:876-87. [PMID: 21061399 DOI: 10.1002/ana.22092] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Mucopolysaccharidosis (MPS) IIIA (Sanfilippo syndrome type A) is a lysosomal storage disorder caused by deficiency of the enzyme sulfamidase. Information on the natural course of MPS IIIA is scarce, but is much needed in view of emerging therapies. METHODS Clinical history and molecular defects of all 110 MPS IIIA patients identified by enzymatic studies in the Netherlands were collected and included in this study. RESULTS First clinical signs, mainly consisting of delayed speech development and behavioral problems, were noted between the ages of 1 and 6 years. Other symptoms included sleeping and hearing problems, recurrent upper airway infections, diarrhea, and epilepsy. The clinical course varied remarkably and could be correlated with the molecular defects. The frequent pathogenic mutations p.R245H, p.Q380R, p.S66W, and c.1080delC were associated with the classical severe phenotype. Patients compound heterozygous for the p.S298P mutation in combination with 1 of the mutations associated with the classical severe phenotype had a significantly longer preservation of psychomotor functions and a longer survival. Two patients homozygous for the p.S298P mutation, and 4 patients from 3 families heterozygous for 3 missense variants not reported previously (p.T421R, p.P180L, and p.L12Q), showed a remarkably attenuated phenotype. INTERPRETATION We report the natural history and mutational analysis in a large unbiased cohort of MPS IIIA patients. We demonstrate that the clinical spectrum of MPS IIIA is much broader than previously reported. A significant genotype-phenotype correlation was established in this cohort.
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Affiliation(s)
- Marlies J Valstar
- Department of Pediatrics and Amsterdam Lysosome Center Sphinx, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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13
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Gabrielli O, Coppa GV, Bruni S, Villani GRD, Pontarelli G, Di Natale P. An adult Sanfilippo type A patient with homozygous mutation R206P in the sulfamidase gene. Am J Med Genet A 2005; 133A:85-9. [PMID: 15637719 DOI: 10.1002/ajmg.a.30552] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The Sanfilippo type A syndrome, one of the most frequent forms of mucopolysaccharidosis III, is characterized by severe mental retardation, progressive neurological degeneration, and mild somatic changes. It is due to a deficiency of heparan-N-sulfatase (sulfamidase) activity and consequent excretion of heparan sulfate in the urine. The disease is transmitted through an autosomal recessive mechanism, and more than 60 gene mutations have been identified. Up to now, only 10 cases of attenuated form of Sanfilippo type A syndrome have been described, and the specific mutation has been identified only in two of them. We report here on a female patient, 20 years old, with Sanfilippo type A syndrome presenting with a mild clinical phenotype characterized essentially by a moderate nonevolving mental retardation. The genetic analysis demonstrated that the patient is homozygous for mutation R206P; presence of polymorphism R456H was also found. This study places R206P as a mild mutation underlying Sanfilippo type A disease.
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Affiliation(s)
- Orazio Gabrielli
- Institute of Maternal-Infantile Sciences, Polytechnic University of Marche, Ancona, Italy.
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14
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Zeegers MPA, van Poppel F, Vlietinck R, Spruijt L, Ostrer H. Founder mutations among the Dutch. Eur J Hum Genet 2005; 12:591-600. [PMID: 15010701 DOI: 10.1038/sj.ejhg.5201151] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Many genetic disorders demonstrate mutations that can be traced to a founder, sometimes a person who can be identified. These founder mutations have generated considerable interest, because they facilitate studies of prevalence and penetrance and can be used to quantify the degree of homogeneity within a population. This paper reports on founder mutations among the Dutch and relates their occurrence to the history and demography of the Netherlands. International migration, regional and religious endogamy, and rapid population growth played key roles in shaping the Dutch population. In the first millenniums BC and AD, the Netherlands were invaded by Celts, Romans, Huns, and Germans. In more recent times, large numbers of Huguenots and Germans migrated into the Netherlands. Population growth within the Netherlands was slow until the 19th century, when a period of rapid population growth started. Today, the Dutch population numbers 16 million inhabitants. Several different classes of founder mutations have been identified among the Dutch. Some mutations occur among people who represent genetic isolates within this country. These include mutations for benign familial cholestasis, diabetes mellitus, type I, infantile neuronal ceroid lipofuscinosis, L-DOPA responsive dystonia, and triphalangeal thumb. Although not related to a specific isolate, other founder mutations were identified only within the Netherlands, including those predisposing for hereditary breast-ovarian cancer, familial hypercholesterolemia, frontotemporal dementia, hereditary paragangliomas, juvenile neuronal ceroid lipofuscinosis, malignant melanoma, protein C deficiency, and San Filippo disease. Many of these show a regional distribution, suggesting dissemination from a founder. Some mutations that occur among the Dutch are shared with other European populations and others have been transmitted by Dutch émigrés to their descendents in North America and South Africa. The occurrence of short chromosomal regions that have remained identical by descent has resulted in relatively limited genetic heterogeneity for many genetic conditions among the Dutch. These observations demonstrate the opportunity for gene discovery for other diseases and traits in the Netherlands.
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MESH Headings
- Alleles
- Female
- Founder Effect
- Gene Frequency/genetics
- Genetic Diseases, Inborn/genetics
- Genetics, Population
- History, 15th Century
- History, 16th Century
- History, 17th Century
- History, 18th Century
- History, 19th Century
- History, 20th Century
- History, 21st Century
- History, Ancient
- History, Medieval
- Humans
- Male
- Mutation/genetics
- Netherlands
- Pedigree
- White People/genetics
- White People/history
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Affiliation(s)
- Maurice P A Zeegers
- Department of Epidemiology, Maastricht University, PO Box 616, 6200 MD, Maastricht, The Netherlands
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15
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Muschol N, Storch S, Ballhausen D, Beesley C, Westermann JC, Gal A, Ullrich K, Hopwood JJ, Winchester B, Braulke T. Transport, enzymatic activity, and stability of mutant sulfamidase (SGSH) identified in patients with mucopolysaccharidosis type III A. Hum Mutat 2004; 23:559-66. [PMID: 15146460 DOI: 10.1002/humu.20037] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Mucopolysaccharidosis type IIIA (MPSIIIA) is an autosomal recessive lysosomal storage disease caused by mutations in the N-sulfoglucosamine sulfohydrolase gene (SGSH; encoding sulfamidase, also sulphamidase) leading to the lysosomal accumulation and urinary excretion of heparan sulfate. Considerable variation in the onset and severity of the clinical phenotype is observed. We report here on expression studies of four novel mutations: c.318C>A (p.Ser106Arg), c.488T>C (p.Leu163Pro), c.571G>A (p.Gly191Arg), and c.1207_1209delTAC (p.Tyr403del), and five previously known mutations: c.220C>T (p.Arg74Cys), c.697C>T (p.Arg233X), c.1297C>T (p.Arg433Trp), c.1026dupC (p.Leu343fsX158), and c.1135delG (p.Val379fsX33) identified in MPSIIIA patients. Transient expression of mutant sulfamidases in BHK or CHO cells revealed that all the mutants were enzymatically inactive with the exception of c.318C>A (p.Ser106Arg), which showed 3.3% activity of the expressed wild-type enzyme. Western blot analysis demonstrated that the amounts of expressed mutant sulfamidases were significantly reduced compared with cells expressing wild type. No polypeptides were immunodetectable in extracts of cells transfected with the cDNA carrying the c.697C>T (p.Arg233X) nonsense mutation. In vitro translation and pulse-chase experiments showed that rapid degradation rather than a decrease in synthesis is responsible for the low, steady-state level of the mutant proteins in cells. The amounts of secreted mutant precursor forms, the cellular stability, the proteolytic processing, and data from double-label immunofluorescence microscopy suggest that the degradation of the majority of newly synthesized c.220C>T (p.Arg74Cys), c.571G>A (p.Gly191Arg), c.1297C>T (p.Arg433Trp), c.1026dupC (p.Leu343fsX158), and c.1135delG (p.Val379fsX33) mutant proteins probably occurs in the ER, whereas c.488T>C (p.Leu163Pro) mutant protein showed instability in the lysosomes.
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Affiliation(s)
- Nicole Muschol
- Department of Biochemistry, Children's Hospital, University Hospital Hamburg Eppendorf, Hamburg, Germany
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16
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Rady PL, Surendran S, Vu AT, Hawkins JC, Michals-Matalon K, Tyring SK, Merren J, Kumar AK, Matalon R. Founder mutation R245H of Sanfilippo syndrome type A in the Cayman Islands. GENETIC TESTING 2003; 6:211-5. [PMID: 12490062 DOI: 10.1089/109065702761403388] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sanfilippo A syndrome is an autosomal recessive lysosomal storage disease. This disease was reported in the Cayman Islands population with carrier frequency of 1/7 to 1/10 in the West Bay district of Grand Cayman. The carrier testing of Sanfilippo A disease for families at risk was carried out using the thermal characteristics of sulfamidase activity. In the present study, a search for mutations in the sulfamidase gene in an index family was performed. In addition, 77 individuals, relatives of children with Sanfilippo A syndrome, were also studied by single-strand conformation polymorphism (SSCP), restriction fragment-length polymorphism (RFLP) analyses, and sequencing. A single mutation, G746A (R245H), was found in the family, with the patient being homozygous and both parents and 1 of the 3 siblings being carriers. Among the 77 family members of the patient with Sanfilippo syndrome, the same mutation was found among carriers of the disease. The finding of a single mutation supports the idea of a founder effect, which facilitates accurate carrier identification of Sanfilippo A syndrome in the population of Cayman Islands.
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Affiliation(s)
- Peter L Rady
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas 77555, USA
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17
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Lee-Chen GJ, Lin SP, Ko MH, Chuang CK, Chen CP, Lee HH, Cheng SC, Shen CH, Tseng KL, Li CL. Identification and characterization of mutations underlying Sanfilippo syndrome type A (mucopolysaccharidosis type IIIA). Clin Genet 2002; 61:192-7. [PMID: 12000360 DOI: 10.1034/j.1399-0004.2002.610304.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Sanfilippo syndrome type A (mucopolysaccharidosis type IIIA; MPS IIIA) is caused by a deficiency of the lysosomal enzyme haparan N-sulphatase (NS). The genomic DNA segments of the NS gene from two Chinese patients with MPS IIIA were amplified by polymerase chain reaction, followed by DNA sequencing to study the molecular lesions. Four mutations (i.e. N42K, D235N, P293S and R377C) and five polymorphisms (i.e. IVS2-72A --> G, IVS2-26T --> C, IVS5+17C --> T, IVS5-37GC --> CTGT and R456H) were identified. Transfection of COS-7 cells with cDNA mutagenized to the corresponding mutations did not yield active enzyme, demonstrating the deleterious nature of the mutations. Western blot analysis revealed a 62-kDa precursor and 56-kDa mature forms for cells transfected with wild-type and polymorphic R456H enzymes. For cells transfected with mutant enzymes, the reduction in precursor and mature forms suggests an increased degradation of the mutant enzymes. The polymorphic DNA haplotype of the NS gene was analysed in 52 unrelated subjects. All five polymorphisms were in Hardy-Weinberg equilibrium. The strong non-random association among the five polymorphisms suggests little or no recombination in the NS gene.
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Affiliation(s)
- G J Lee-Chen
- Department of Biology, National Taiwan Normal University, Taipei, Taiwan, ROC.
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18
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Litjens T, Hopwood JJ. Mucopolysaccharidosis type VI: Structural and clinical implications of mutations in N-acetylgalactosamine-4-sulfatase. Hum Mutat 2001; 18:282-95. [PMID: 11668612 DOI: 10.1002/humu.1190] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mucopolysaccharidosis type VI (MPS-VI) is an autosomal recessive lysosomal storage disorder caused by the deficiency of N-acetylgalactosamine-4-sulfatase (4S; or ARSB). Mutations in the 4S gene are responsible for 4S deficiency, which leads to the intralysosomal storage of partially degraded glycosaminoglycans, dermatan sulfate, and chondroitin 4-sulfate. To date, a total of 45 clinically relevant mutations have been identified in the human 4S gene. Missense mutations are the largest group, with 31 identified mutations. Nonsense mutations and small insertions or deletions comprise the remainder, with seven mutations each. Six polymorphisms have also been reported: two amino acid substitutions and four silent transitions. Mapping of the missense mutations onto the 4S structure shows that they are distributed throughout the three subunits of the mature 4S polypeptide. Mutations have been identified in active site residues, in residues adjacent to the active site, in potential substrate binding residues, in residues exposed on the surface, and in residues buried within the protein core. Missense mutations have also been identified in disulfide crosslinks. Molecular modeling of MPS-VI mutations onto the 4S structure suggests that the majority cause 4S deficiency via destabilization and the consequent reduction of 4S protein concentration. The vast majority of MPS-VI mutant alleles are either unique to a patient or are present in a small number of patients. So far, no common mutations have been described. Therefore, screening of the general population for MPS-VI alleles will be difficult.
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Affiliation(s)
- T Litjens
- Lysosomal Diseases Research Unit, Department of Chemical Pathology, Women's and Children's Hospital, North Adelaide, South Australia, Australia
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19
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Yogalingam G, Hopwood JJ. Molecular genetics of mucopolysaccharidosis type IIIA and IIIB: Diagnostic, clinical, and biological implications. Hum Mutat 2001; 18:264-81. [PMID: 11668611 DOI: 10.1002/humu.1189] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mucopolysaccharidosis (MPS) types IIIA, B, C, and D are a group of autosomal recessive lysosomal storage diseases caused by mutations in one of four genes which encode enzyme activities required for the lysosomal degradation of heparan sulfate. The progressive lysosomal storage of heparan sulfate eventually results in the clinical onset of disease, which is predominantly characterized by severe central nervous system degeneration. MPS-IIIA and MPS-IIIB involve deficiencies of heparan sulfate sulfamidase (SGSH) and alpha-N-acetylglucosaminidase (NAGLU), respectively. Both the SGSH and NAGLU genes have been cloned and characterized, thereby permitting mutation analysis of MPS-IIIA and MPS-IIIB patients. A total of 62 mutations have now been defined for MPS-IIIA consisting of 46 missense/nonsense mutations, 15 small insertions/deletions, and one splice site mutation. A total of 86 mutations have been identified in the NAGLU gene of MPS-IIIB patients; 58 missense/nonsense mutations, 27 insertions/deletions, and one splice site mutation. Most of the identified mutations in the SGSH and NAGLU genes are associated with severe clinical phenotypes. Many of the missense, nonsense, and insertion/deletion mutations have been expressed in mammalian cell lines to permit the characterization of their effects on SGSH and NAGLU activity and intracellular processing and trafficking. For MPS-IIIA and MPS-IIIB many of the reported mutations are unique making screening the general population difficult. However, molecular characterization of MPS-IIIA patients has revealed a high incidence of particular mutations of different geographical origins, which will be beneficial for the molecular diagnosis of MPS-IIIA.
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Affiliation(s)
- G Yogalingam
- Lysosomal Diseases Research Unit, Department of Chemical Pathology, Women's and Children's Hospital, North Adelaide, South Australia, Australia
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20
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Chabás A, Montfort M, Martínez-Campos M, Díaz A, Coll MJ, Grinberg D, Vilageliu L. Mutation and haplotype analyses in 26 Spanish Sanfilippo syndrome type A patients: possible single origin for 1091delC mutation. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 100:223-8. [PMID: 11343308 DOI: 10.1002/ajmg.1248] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mucopolysaccharidosis IIIA, also known as Sanfilippo syndrome type A, is an autosomal recessive storage disorder caused by deficiency of sulfamidase. The disease results in severe central nervous system degeneration often with mild somatic features that may delay the clinical diagnosis. Molecular analyses would allow early and unequivocal heterozygote detection, providing a useful tool for genetic counselling. About 40 mutations have been reported in the sulfamidase gene, with a very uneven distribution in different patient populations. We have previously described the high prevalence of mutation 1091delC in a small number of Spanish Sanfilippo A patients. The aim of the present work is to extend the mutational study to a total of 26 unrelated patients and perform haplotype analysis in order to study the origin of some mutations. The whole coding region of the gene was scanned by SSCP analysis and sequencing. This allowed the identification of 14 different mutations, corresponding to 90% of the mutant alleles. Seven of these mutations were only found in this Spanish group of patients, three of which, R150W, R433Q and R433W, are described here for the first time. We have also analyzed four internal polymorphisms and constructed the corresponding haplotypes. Chromosomes bearing mutation 1091delC show a conserved haplotype suggesting a common origin for this mutation. Moreover, all other mutations found twice or more also have conserved haplotypes for those polymorphic markers.
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Affiliation(s)
- A Chabás
- Institut de Bioquímica Clínica, Barcelona, Spain.
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21
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Perkins KJ, Byers S, Yogalingam G, Weber B, Hopwood JJ. Expression and characterization of wild type and mutant recombinant human sulfamidase. Implications for Sanfilippo (Mucopolysaccharidosis IIIA) syndrome. J Biol Chem 1999; 274:37193-9. [PMID: 10601282 DOI: 10.1074/jbc.274.52.37193] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mucopolysaccharidosis IIIA (MPS-IIIA) is an autosomal recessive lysosomal storage disorder caused by the deficiency of sulfamidase (NS; EC 3.10.1.1), resulting in defective degradation and storage of heparan sulfate. This paper reports the production and characterization of monoclonal and polyclonal antibodies against recombinant human sulfamidase (rhNS) to quantitate and characterize normal and mutant sulfamidase produced from the wild type NS expression vector. Glycosylation and phosphorylation studies of immunoprecipitated rhNS show that all five potential glycosylation sites are utilized, with three high mannose/hybrid oligosaccharides and two simpler chains, with at least one functional mannose 6-phosphate group. An NS quantification system was developed to determine the effect of the three most common and severe patient mutations: S66W (Italy), R74C (Poland), and R245H (The Netherlands). The quantity and specific activity of expressed mutant rhNS was significantly lower than expressed normal rhNS, with 0.3, 0.2, and 0.05% of normal rhNS produced and 15, 17, and 83% of normal specific activity for S66W, R74C, and R245H observed, respectively. The recent structural elucidation of N-acetylgalactosamine-4-sulfatase was utilized to postulate the effect on the structure-function relationship of NS. The characterization of normal and mutated rhNS has relevance for efficient diagnosis and therapeutic developments for MPS-IIIA patients.
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Affiliation(s)
- K J Perkins
- Lysosomal Disorders Research Unit, Department of Chemical Pathology, Women's and Children's Hospital, 72 King William Rd., North Adelaide, South Australia 5006, Australia
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