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Zanetti A, Tomanin R. Targeting Neurological Aspects of Mucopolysaccharidosis Type II: Enzyme Replacement Therapy and Beyond. BioDrugs 2024; 38:639-655. [PMID: 39177874 PMCID: PMC11358193 DOI: 10.1007/s40259-024-00675-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2024] [Indexed: 08/24/2024]
Abstract
Mucopolysaccharidosis type II (MPS II) is a rare, pediatric, neurometabolic disorder due to the lack of activity of the lysosomal hydrolase iduronate 2-sulfatase (IDS), normally degrading heparan sulfate and dermatan sulfate within cell lysosomes. The deficit of activity is caused by mutations affecting the IDS gene, leading to the pathological accumulation of both glycosaminoglycans in the lysosomal compartment and in the extracellular matrix of most body districts. Although a continuum of clinical phenotypes is described, two main forms are commonly recognized-attenuated and severe-the latter being characterized by an earlier and faster clinical progression and by a progressive impairment of central nervous system (CNS) functions. However, attenuated forms have also been recently described as presenting some neurological involvement, although less deep, such as deficits of attention and hearing loss. The main treatment for the disease is represented by enzyme replacement therapy (ERT), applied in several countries since 2006, which, albeit showing partial efficacy on some peripheral organs, exhibited a very poor efficacy on bones and heart, and a total inefficacy on CNS impairment, due to the inability of the recombinant enzyme to cross the blood-brain barrier (BBB). Together with ERT, whose design enhancements, performed in the last few years, allowed a possible brain penetration of the drug through the BBB, other therapeutic approaches aimed at targeting CNS involvement in MPS II were proposed and evaluated in the last decades, such as intrathecal ERT, intracerebroventricular ERT, ex vivo gene therapy, or adeno-associated viral vector (AAV) gene therapy. The aim of this review is to summarize the main clinical aspects of MPS II in addition to current therapeutic options, with particular emphasis on the neurological ones and on the main CNS-targeted therapeutic approaches explored through the years.
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Affiliation(s)
- Alessandra Zanetti
- Laboratory of Diagnosis and Therapy of Lysosomal Disorders, Department of Women's and Children's Health SDB, University of Padova, Via Giustiniani, 3, 35128, Padua, Italy
- Istituto di Ricerca Pediatrica Città della Speranza, 35127, Padua, Italy
| | - Rosella Tomanin
- Laboratory of Diagnosis and Therapy of Lysosomal Disorders, Department of Women's and Children's Health SDB, University of Padova, Via Giustiniani, 3, 35128, Padua, Italy.
- Istituto di Ricerca Pediatrica Città della Speranza, 35127, Padua, Italy.
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Rossi A, Brunetti-Pierri N. Gene therapies for mucopolysaccharidoses. J Inherit Metab Dis 2024; 47:135-144. [PMID: 37204267 DOI: 10.1002/jimd.12626] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/27/2023] [Accepted: 05/15/2023] [Indexed: 05/20/2023]
Abstract
Current specific treatments for mucopolysaccharidoses (MPSs) include enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT). Both treatments are hampered by several limitations, including lack of efficacy on brain and skeletal manifestations, need for lifelong injections, and high costs. Therefore, more effective treatments are needed. Gene therapy in MPSs is aimed at obtaining high levels of the therapeutic enzyme in multiple tissues either by engrafted gene-modified hematopoietic stem progenitor cells (ex vivo) or by direct infusion of a viral vector expressing the therapeutic gene (in vivo). This review focuses on the most recent clinical progress in gene therapies for MPSs. The various gene therapy approaches with their strengths and limitations are discussed.
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Affiliation(s)
- Alessandro Rossi
- Department of Translational Medicine, Federico II University of Naples, Naples, Italy
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, Federico II University of Naples, Naples, Italy
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomics and Experimental Medicine Program, University of Naples Federico II, Naples, Italy
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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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Elvidge KL, Christodoulou J, Farrar MA, Tilden D, Maack M, Valeri M, Ellis M, Smith NJC. The collective burden of childhood dementia: a scoping review. Brain 2023; 146:4446-4455. [PMID: 37471493 PMCID: PMC10629766 DOI: 10.1093/brain/awad242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/16/2023] [Accepted: 06/25/2023] [Indexed: 07/22/2023] Open
Abstract
Childhood dementia is a devastating and under-recognized group of disorders with a high level of unmet need. Typically monogenic in origin, this collective of individual neurodegenerative conditions are defined by a progressive impairment of neurocognitive function, presenting in childhood and adolescence. This scoping review aims to clarify definitions and conceptual boundaries of childhood dementia and quantify the collective disease burden. A literature review identified conditions that met the case definition. An expert clinical working group reviewed and ratified inclusion. Epidemiological data were extracted from published literature and collective burden modelled. One hundred and seventy genetic childhood dementia disorders were identified. Of these, 25 were analysed separately as treatable conditions. Collectively, currently untreatable childhood dementia was estimated to have an incidence of 34.5 per 100 000 (1 in 2900 births), median life expectancy of 9 years and prevalence of 5.3 per 100 000 persons. The estimated number of premature deaths per year is similar to childhood cancer (0-14 years) and approximately 70% of those deaths will be prior to adulthood. An additional 49.8 per 100 000 births are attributable to treatable conditions that would cause childhood dementia if not diagnosed early and stringently treated. A relational database of the childhood dementia disorders has been created and will be continually updated as new disorders are identified (https://knowledgebase.childhooddementia.org/). We present the first comprehensive overview of monogenic childhood dementia conditions and their collective epidemiology. Unifying these conditions, with consistent language and definitions, reinforces motivation to advance therapeutic development and health service supports for this significantly disadvantaged group of children and their families.
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Affiliation(s)
| | - John Christodoulou
- Brain and Mitochondrial Research Group, Murdoch Children’s Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michelle A Farrar
- Department of Neurology, Sydney Children's Hospital Network, Randwick, NSW 2031, Australia
- Discipline of Paediatrics, School of Clinical Medicine, UNSW Medicine and Health, Sydney, NSW 2052, Australia
| | | | - Megan Maack
- Childhood Dementia Initiative, Brookvale, NSW 2100, Australia
| | | | - Magda Ellis
- THEMA Consulting Pty Ltd, Pyrmont, NSW 2009, Australia
| | - Nicholas J C Smith
- Discipline of Paediatrics, University of Adelaide, Women's and Children's Hospital, North Adelaide, South Australia 5006, Australia
- Department of Neurology and Clinical Neurophysiology, Women’s and Children’s Health Network, North Adelaide, South Australia 5006, Australia
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